Colliding galaxies: NGC 520

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjERhTZbK6UkBmrM28_FTUvaXuw3T1gdif6SrAQrDkjFdyDIAW1e5rwP1apfEAHiSBSELvT45Faz2-ceudYEiI358rPQVCM5ZKGyC0VXOLLgYbT2JJTyR5kao2IcUB36kNrbiYSHnTCdGa1/s1600/NGC-520.jpg" imageanchor="1"><img alt="NGC 520" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjERhTZbK6UkBmrM28_FTUvaXuw3T1gdif6SrAQrDkjFdyDIAW1e5rwP1apfEAHiSBSELvT45Faz2-ceudYEiI358rPQVCM5ZKGyC0VXOLLgYbT2JJTyR5kao2IcUB36kNrbiYSHnTCdGa1/s640/NGC-520.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">NGC 520 is the product of a collision between two disc galaxies that started 300 million years ago. It exemplifies the middle stages of the merging process: the discs of the parent galaxies have merged together, but the nuclei have not yet coalesced. It features an odd-looking tail of stars and a prominent dust lane that runs diagonally across the centre of the image and obscures the galaxy. NGC 520 is one of the brightest galaxy pairs on the sky, and can be observed with a small telescope toward the constellation of Pisces, the Fish, having the appearance of a comet. It is about 100 million light-years away and about 100,000 light-years across. The galaxy pair is included in Arp's catalogue of peculiar galaxies as ARP 157.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">This image is part of a large collection of 59 images of merging galaxies taken by the Hubble Space Telescope and released on the occasion of its 18th anniversary on 24th April 2008.</div><br />Image Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and B. Whitmore (STScI)<br />Explanation from: https://www.spacetelescope.org/images/heic0810aq/

Colliding galaxies: NGC 520

NGC 520 is the product of a collision between two disc galaxies that started 300 million years ago. It exemplifies the middle stages of the ...

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Earth seen by Japan’s Himawari-8 Satellite from 22 000 miles (35 400 km) away

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtWNNb3NBwsYhh2V5UAiJLLwX_KIAU3kD9YR3EZQUO5gSFbv3J1sQOHVv5eyqphJVq2dvbyGq3DugNN5zAOj9ftIS-heh9CRGrtWz2WyTOVXcW88oasgDiumzs3BBHoEcLYSC-nzXRCz9j/s1600/earth-from-space.gif" imageanchor="1"><img alt="Earth from Space" border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtWNNb3NBwsYhh2V5UAiJLLwX_KIAU3kD9YR3EZQUO5gSFbv3J1sQOHVv5eyqphJVq2dvbyGq3DugNN5zAOj9ftIS-heh9CRGrtWz2WyTOVXcW88oasgDiumzs3BBHoEcLYSC-nzXRCz9j/s320/earth-from-space.gif" title="" width="320" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Himawari-8 Satellite, Orbit of the Earth</div><div style="text-align: center;">July 2015</div><br />Video Credit: JMA<br /><div></div>

Earth seen by Japan’s Himawari-8 Satellite from 22 000 miles (35 400 km) away

Himawari-8 Satellite, Orbit of the Earth July 2015 Video Credit: JMA

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Earth's Atmosphere seen from International Space Station

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioP5HNMgpMkZOMwOxDakdHloulMRnK0f3TizaLtTctUC5splngV0z_pUlBCN3LcCeUBCFP67jz0juTSxPf0yXqeaWgyGrZKppetsF9KZn70y18M4-ewtraQ_SeJBSFU6n35HOkJ19cO5P6/s1600/Earths-Atmosphere.JPG" imageanchor="1"><img alt="Earth's Atmosphere" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioP5HNMgpMkZOMwOxDakdHloulMRnK0f3TizaLtTctUC5splngV0z_pUlBCN3LcCeUBCFP67jz0juTSxPf0yXqeaWgyGrZKppetsF9KZn70y18M4-ewtraQ_SeJBSFU6n35HOkJ19cO5P6/s640/Earths-Atmosphere.JPG" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">ISS, Orbit of the Earth</div><div style="text-align: center;">February 2016</div><br />Image Credit: NASA/ESA<br /><div></div>

Earth's Atmosphere seen from International Space Station

ISS, Orbit of the Earth February 2016 Image Credit: NASA/ESA

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A spiral galaxy crowned by a star

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4IOKYKEtw2IxbHvLYGUJ7Uz9dpGEMZvwV8NGtr1NL6s3VJTOmjhihBZqwzC9N1WSfalPgGa5yhNhCxdspnMVbELxgxEDrZnmLe7OkfGHNTNeeGRwOJ1siec6FlhndbvtUiFVeZrCwBVjc/s1600/NGC-4517.jpg" imageanchor="1"><img alt="NGC 4517" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4IOKYKEtw2IxbHvLYGUJ7Uz9dpGEMZvwV8NGtr1NL6s3VJTOmjhihBZqwzC9N1WSfalPgGa5yhNhCxdspnMVbELxgxEDrZnmLe7OkfGHNTNeeGRwOJ1siec6FlhndbvtUiFVeZrCwBVjc/s640/NGC-4517.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Another treasure unearthed from the Hubble archives, this beautiful image shows a spiral galaxy named NGC 4517. Slightly bigger than our Milky Way, it is seen edge-on, crowned by a very bright star. The star is actually much closer to us than the galaxy, explaining why it appears to be so big and bright in the picture. </div><div style="text-align: center;"><br /></div><div style="text-align: center;">NGC 4517 is located approximately 40 million light-years away in the constellation of Virgo (The Virgin). It has a bright centre, but this is not visible in this Hubble image. Its orientation has led to it being included in many studies of globular clusters, clumps of stars that orbit the centres of galaxies like satellites.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The galaxy was discovered in 1784 by William Herschel, who described this region as having “a pretty bright star situated exactly north of the centre of an extended milky ray”. Of course the “milky ray” seen by Herschel is actually this spiral galaxy, but with his 17th century observing gear he could only tell that there a fuzzy, blurry structure below the much brighter star.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">This image is composed from visible and infrared light gathered by NASA/ESA Hubble Space Telescope.</div><br />Image Credit: ESA/Hubble & NASA, Gilles Chapdelaine<br />Explanation from: http://www.spacetelescope.org/images/potw1330a/

A spiral galaxy crowned by a star

Another treasure unearthed from the Hubble archives, this beautiful image shows a spiral galaxy named NGC 4517. Slightly bigger than our Mil...

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Comparison of the Earth to Neptune

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPupi3rR9cEI8eqi7GmwzRxBuxoBdB7XWHeQFfIntuU1dKuzQdWwHBMYZEOw2NE7QtLJBAuh5ud5KFb0Qi08H3GNPcAMfRrxO1k4Det9fuaWpbk9udPULpeg9Cxvat13JOaXwONhKxohx3/s1600/Comparison-of-the-Earth-to-Neptune.jpg" imageanchor="1"><img alt="Comparison of the Earth to Neptune" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPupi3rR9cEI8eqi7GmwzRxBuxoBdB7XWHeQFfIntuU1dKuzQdWwHBMYZEOw2NE7QtLJBAuh5ud5KFb0Qi08H3GNPcAMfRrxO1k4Det9fuaWpbk9udPULpeg9Cxvat13JOaXwONhKxohx3/s640/Comparison-of-the-Earth-to-Neptune.jpg" title="" /></a></div><br /><div style="text-align: center;"><span style="font-family: "georgia" , "times new roman" , serif; font-size: x-large;">The Earth</span></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to harbor life.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">According to evidence from radiometric dating and other sources, Earth was formed about 4.54 billion years ago. Earth gravitationally interacts with other objects in space, especially the Sun and the Moon. During one orbit around the Sun, Earth rotates about its own axis 366.26 times, creating 365.26 solar days or one sidereal year. Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). The Moon is Earth's only permanent natural satellite. Its gravitational interaction with Earth causes ocean tides, stabilizes the orientation of Earth's rotational axis, and gradually slows Earth's rotational rate.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. 71% of Earth's surface is covered with water, with the remainder consisting of continents and islands that together have many lakes and other sources of water that contribute to the hydrosphere. Earth's polar regions are mostly covered with ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the magnetic field, and a convecting mantle that drives plate tectonics.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Within its first billion years, life appeared in Earth's oceans and began to affect its atmosphere and surface, promoting the proliferation of aerobic as well as anaerobic organisms. Since then, the combination of Earth's distance from the Sun, its physical properties and its geological history have allowed life to thrive and evolve. The earliest undisputed life on Earth arose at least 3.5 billion years ago. Earlier physical evidence of life includes biogenic graphite in 3.7 billion-year-old metasedimentary rocks discovered in southwestern Greenland, as well as "remains of biotic life" found in 4.1 billion-year-old rocks in Western Australia. Earth's biodiversity has expanded continually except when interrupted by mass extinctions. Although scholars estimate that over 99% of all species of life (over five billion) that ever lived on Earth are extinct, there are still an estimated 10–14 million extant species, of which about 1.2 million have been documented and over 86% have not yet been described. Over 7.3 billion humans live on Earth and depend on its biosphere and minerals for their survival. Earth's human population is divided among about two hundred sovereign states which interact through diplomacy, conflict, travel, trade and communication media.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><br /></div><div style="text-align: center;"><span style="font-family: "georgia" , "times new roman" , serif; font-size: x-large;">Neptune</span></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Neptune is the eighth and farthest known planet from the Sun in the Solar System. It is the fourth-largest planet by diameter and the third-largest by mass. Among the giant planets in the Solar System, Neptune is the most dense. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune. Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 astronomical units (4.50×109 km). Named after the Roman god of the sea, its astronomical symbol is ♆, a stylised version of the god Neptune's trident.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Neptune is not visible to the unaided eye and is the only planet in the Solar System found by mathematical prediction rather than by empirical observation. Unexpected changes in the orbit of Uranus led Alexis Bouvard to deduce that its orbit was subject to gravitational perturbation by an unknown planet. Neptune was subsequently observed with a telescope on 23 September 1846 by Johann Galle within a degree of the position predicted by Urbain Le Verrier. Its largest moon, Triton, was discovered shortly thereafter, though none of the planet's remaining known 14 moons were located telescopically until the 20th century. The planet's distance from Earth gives it a very small apparent size, making it challenging to study with Earth-based telescopes. Neptune was visited by Voyager 2, when it flew by the planet on 25 August 1989. The advent of Hubble Space Telescope and large ground-based telescopes with adaptive optics has recently allowed for additional detailed observations from afar.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Neptune is similar in composition to Uranus, and both have compositions that differ from those of the larger gas giants, Jupiter and Saturn. Like Jupiter and Saturn, Neptune's atmosphere is composed primarily of hydrogen and helium, along with traces of hydrocarbons and possibly nitrogen, but it contains a higher proportion of "ices" such as water, ammonia, and methane. Scientists sometimes categorise Uranus and Neptune as "ice giants" to emphasise this distinction. The interior of Neptune, like that of Uranus, is primarily composed of ices and rock. Traces of methane in the outermost regions in part account for the planet's blue appearance.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">In contrast to the hazy, relatively featureless atmosphere of Uranus, Neptune's atmosphere has active and visible weather patterns. For example, at the time of the Voyager 2 flyby in 1989, the planet's southern hemisphere had a Great Dark Spot comparable to the Great Red Spot on Jupiter. These weather patterns are driven by the strongest sustained winds of any planet in the Solar System, with recorded wind speeds as high as 2,100 kilometres per hour (580 m/s; 1,300 mph). Because of its great distance from the Sun, Neptune's outer atmosphere is one of the coldest places in the Solar System, with temperatures at its cloud tops approaching 55 K (−218 °C). Temperatures at the planet's centre are approximately 5,400 K (5,100 °C). Neptune has a faint and fragmented ring system (labelled "arcs"), which was first detected during the 1960s and confirmed by Voyager 2.</div><br />Explanation from: https://en.wikipedia.org/wiki/Earth and https://en.wikipedia.org/wiki/Neptune

Comparison of the Earth to Neptune

The Earth Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrest...

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Sun's reflection on lake seen from the International Space Station

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgLXbFRzy70d6_Bi1DZKt47o8yrrGB0y8rryqj6RSyx5QUTgMYVIRXZlldF7l3VDWIijKCckwCwiVmAi4mjCiTtAJhZZELwfBiiI4EYfp2DcyC2gSCQAqVsHjQqUUPzHemrdAQiInhXhRWA/s1600/lake-from-iss.jpg" imageanchor="1"><img alt="lake from iss" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgLXbFRzy70d6_Bi1DZKt47o8yrrGB0y8rryqj6RSyx5QUTgMYVIRXZlldF7l3VDWIijKCckwCwiVmAi4mjCiTtAJhZZELwfBiiI4EYfp2DcyC2gSCQAqVsHjQqUUPzHemrdAQiInhXhRWA/s640/lake-from-iss.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">ISS, Orbit of the Earth</div><div style="text-align: center;">June 2014</div><br />Image Credit: NASA/ESA<br /><div></div>

Sun's reflection on lake seen from the International Space Station

ISS, Orbit of the Earth June 2014 Image Credit: NASA/ESA

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2015 Total Solar Eclipse seen from plane

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjw0QmaAVL64AUDaBjQ3_9wX4HioqqgOXYImLTAV9YPJwSjgXdimbnx2xAUt3hLzdkKjF9XS3DJj_ToWoKU5TjdEM0MxW0pmJIC-WJArInvt13rwYewMpovIJoKbUwGyI4gqVQRIix8fmmF/s1600/Total-Solar-Eclipse-from-plane.gif" imageanchor="1"><img alt="Total Solar Eclipse seen from plane" border="0" height="358" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjw0QmaAVL64AUDaBjQ3_9wX4HioqqgOXYImLTAV9YPJwSjgXdimbnx2xAUt3hLzdkKjF9XS3DJj_ToWoKU5TjdEM0MxW0pmJIC-WJArInvt13rwYewMpovIJoKbUwGyI4gqVQRIix8fmmF/s640/Total-Solar-Eclipse-from-plane.gif" title="" width="640" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">March 20, 2015</div><br />Video Credit & Copyright: Roman Impolitov

2015 Total Solar Eclipse seen from plane

March 20, 2015 Video Credit & Copyright: Roman Impolitov

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Sunrise seen from International Space Station

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjnMPWTbOX-DE6E3pTFIaRDVGQe2udhhG6_ldsPbkJeyaw7pUtQm1ouEkXdWiXvZW0H64CsOwOPHIfu2yIvvVriYo5gyQcwMiIKu921zbRYbrL732XYK1rqQX3HwW3yvp0teLlZO0lj7yJc/s1600/sunrise-from-iss.JPG" imageanchor="1"><img alt="sunrise from iss" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjnMPWTbOX-DE6E3pTFIaRDVGQe2udhhG6_ldsPbkJeyaw7pUtQm1ouEkXdWiXvZW0H64CsOwOPHIfu2yIvvVriYo5gyQcwMiIKu921zbRYbrL732XYK1rqQX3HwW3yvp0teLlZO0lj7yJc/s640/sunrise-from-iss.JPG" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">ISS, Orbit of the Earth</div><div style="text-align: center;">January 2016</div><br />Image Credit: NASA/ESA

Sunrise seen from International Space Station

ISS, Orbit of the Earth January 2016 Image Credit: NASA/ESA

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Comparison of the Earth to the Rings of Saturn

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNmFVA39XaYe53v2yrMt-HEuVJ6J2mpVPzaFhyn3WL5hIG4DEQWEuvhIh2XZKYi79SfMJP6rWMV8xBmBs9CpzRj5gTyVtF8mpfo42am2UuvRgMpgvKIuvD6O5LzHNFU3WKiKDcPcsullc9/s1600/Comparison-of-the-Earth-to-Rings-of-Saturn.jpg" imageanchor="1"><img alt="Comparison of the Earth to the Rings of Saturn" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNmFVA39XaYe53v2yrMt-HEuVJ6J2mpVPzaFhyn3WL5hIG4DEQWEuvhIh2XZKYi79SfMJP6rWMV8xBmBs9CpzRj5gTyVtF8mpfo42am2UuvRgMpgvKIuvD6O5LzHNFU3WKiKDcPcsullc9/s640/Comparison-of-the-Earth-to-Rings-of-Saturn.jpg" title="" /></a></div><br /><div style="text-align: center;"><span style="font-family: "georgia" , "times new roman" , serif; font-size: x-large;">The Earth</span></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to harbor life.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">According to evidence from radiometric dating and other sources, Earth was formed about 4.54 billion years ago. Earth gravitationally interacts with other objects in space, especially the Sun and the Moon. During one orbit around the Sun, Earth rotates about its own axis 366.26 times, creating 365.26 solar days or one sidereal year. Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). The Moon is Earth's only permanent natural satellite. Its gravitational interaction with Earth causes ocean tides, stabilizes the orientation of Earth's rotational axis, and gradually slows Earth's rotational rate.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. 71% of Earth's surface is covered with water, with the remainder consisting of continents and islands that together have many lakes and other sources of water that contribute to the hydrosphere. Earth's polar regions are mostly covered with ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the magnetic field, and a convecting mantle that drives plate tectonics.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Within its first billion years, life appeared in Earth's oceans and began to affect its atmosphere and surface, promoting the proliferation of aerobic as well as anaerobic organisms. Since then, the combination of Earth's distance from the Sun, its physical properties and its geological history have allowed life to thrive and evolve. The earliest undisputed life on Earth arose at least 3.5 billion years ago. Earlier physical evidence of life includes biogenic graphite in 3.7 billion-year-old metasedimentary rocks discovered in southwestern Greenland, as well as "remains of biotic life" found in 4.1 billion-year-old rocks in Western Australia. Earth's biodiversity has expanded continually except when interrupted by mass extinctions. Although scholars estimate that over 99% of all species of life (over five billion) that ever lived on Earth are extinct, there are still an estimated 10–14 million extant species, of which about 1.2 million have been documented and over 86% have not yet been described. Over 7.3 billion humans live on Earth and depend on its biosphere and minerals for their survival. Earth's human population is divided among about two hundred sovereign states which interact through diplomacy, conflict, travel, trade and communication media.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><br /></div><div style="text-align: center;"><span style="font-family: "georgia" , "times new roman" , serif; font-size: x-large;">Rings of Saturn</span></div><div style="text-align: center;"><br /></div><div style="text-align: center;">The rings of Saturn are the most extensive planetary ring system of any planet in the Solar System. They consist of countless small particles, ranging in size from micrometres to metres, that orbit about Saturn. The ring particles are made almost entirely of water ice, with a trace component of rocky material. There is still no consensus as to their mechanism of formation; some features of the rings suggest a relatively recent origin, but theoretical models indicate they are likely to have formed early in the Solar System's history.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Although reflection from the rings increases Saturn's brightness, they are not visible from Earth with unaided vision. In 1610, the year after Galileo Galilei first turned a telescope to the sky, he became the very first person to observe Saturn's rings, though he could not see them well enough to discern their true nature. In 1655, Christiaan Huygens was the first person to describe them as a disk surrounding Saturn. Although many people think of Saturn's rings as being made up of a series of tiny ringlets (a concept that goes back to Laplace), true gaps are few. It is more correct to think of the rings as an annular disk with concentric local maxima and minima in density and brightness. On the scale of the clumps within the rings there is much empty space.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The rings have numerous gaps where particle density drops sharply: two opened by known moons embedded within them, and many others at locations of known destabilizing orbital resonances with Saturn's moons. Other gaps remain unexplained. Stabilizing resonances, on the other hand, are responsible for the longevity of several rings, such as the Titan Ringlet and the G Ring.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Well beyond the main rings is the Phoebe ring, which is tilted at an angle of 27 degrees to the other rings and, like Phoebe, orbits in retrograde fashion.</div><br />Explanation from: https://en.wikipedia.org/wiki/Earth and https://en.wikipedia.org/wiki/Rings_of_Saturn

Comparison of the Earth to the Rings of Saturn

The Earth Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrest...

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The unique Red Rectangle: sharper than ever before

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgG9KDOd3Q6GARbRZRoj72NIk2Vf8n64lQhmBPGS1i3eXmD-zQU5yvLNszGZW-jceQabliC0-rzxZ3SFoCsYC91OO2N1cmT9YRpiQkXnZGLtTkcreZG_RTLwNMwEL3pJaKuVvP2LIkF6IR8/s1600/Red-Rectangle.jpg" imageanchor="1"><img alt="Red Rectangle" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgG9KDOd3Q6GARbRZRoj72NIk2Vf8n64lQhmBPGS1i3eXmD-zQU5yvLNszGZW-jceQabliC0-rzxZ3SFoCsYC91OO2N1cmT9YRpiQkXnZGLtTkcreZG_RTLwNMwEL3pJaKuVvP2LIkF6IR8/s640/Red-Rectangle.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">The star HD 44179 is surrounded by an extraordinary structure known as the Red Rectangle. It acquired its moniker because of its shape and its apparent colour when seen in early images from Earth. This strikingly detailed Hubble image reveals how, when seen from space, the nebula, rather than being rectangular, is shaped like an X with additional complex structures of spaced lines of glowing gas, a little like the rungs of a ladder.The star at the centre is similar to the Sun, but at the end of its lifetime, pumping out gas and other material to make the nebula, and giving it the distinctive shape.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">It also appears that the star is a close binary that is surrounded by a dense torus of dust — both of which may help to explain the very curious shape. Precisely how the central engine of this remarkable and unique object spun the gossamer threads of nebulosity remains mysterious. It is likely that precessing jets of material played a role.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The Red Rectangle is an unusual example of what is known as a proto-planetary nebula. These are old stars, on their way to becoming planetary nebulae. Once the expulsion of mass is complete a very hot white dwarf star will remain and its brilliant ultraviolet radiation will cause the surrounding gas to glow. The Red Rectangle is found about 2 300 light-years away in the constellation Monoceros (the Unicorn).</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The High Resolution Channel of the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys captured this view of HD 44179 and the surrounding Red Rectangle nebula — the sharpest view so far. Red light from glowing Hydrogen was captured through the F658N filter and coloured red. Orange-red light over a wider range of wavelengths through a F625W filter was coloured blue.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The field of view is about 25 by 20 arcseconds.</div><br />Image Credit: ESA/Hubble and NASA<br />Explanation from: http://www.spacetelescope.org/images/potw1007a/

The unique Red Rectangle: sharper than ever before

The star HD 44179 is surrounded by an extraordinary structure known as the Red Rectangle. It acquired its moniker because of its shape and i...

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Solar Eclipse seen by DSCOVR Observatory

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6VZJ_CadkDqcl_yWlOAth_70f4mqCaX6S6xlNuOhIpQRKa5E8Ahyphenhyphen6UZwmvVJDHvvi1IW3q44mxeXlQwNCTsuNqXEoCSiozS9BtFXHUcv9dn6DqnEChAFlKPjYHZotJjB4pE5jOyeiQKy3/s1600/Solar-Eclipse-from-Space-01.jpg" imageanchor="1"><img alt="solar eclipse from space" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6VZJ_CadkDqcl_yWlOAth_70f4mqCaX6S6xlNuOhIpQRKa5E8Ahyphenhyphen6UZwmvVJDHvvi1IW3q44mxeXlQwNCTsuNqXEoCSiozS9BtFXHUcv9dn6DqnEChAFlKPjYHZotJjB4pE5jOyeiQKy3/s320/Solar-Eclipse-from-Space-01.jpg" title="" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgN6NZiJSVGqwuCmTD9d0r_e8RaZHBHfP8pxWbJ188dUqvHA8X8GgbnLYYhIdR_wpLYCe6U9sg4lojCn6pleMdKcOMqxpbbKxrQ0jXlK_GXyyhBtxEJkd8FJsFyJpoTRyHcPg-kHMCIcXNr/s1600/Solar-Eclipse-from-Space-02.jpg" imageanchor="1"><img alt="solar eclipse" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgN6NZiJSVGqwuCmTD9d0r_e8RaZHBHfP8pxWbJ188dUqvHA8X8GgbnLYYhIdR_wpLYCe6U9sg4lojCn6pleMdKcOMqxpbbKxrQ0jXlK_GXyyhBtxEJkd8FJsFyJpoTRyHcPg-kHMCIcXNr/s320/Solar-Eclipse-from-Space-02.jpg" title="" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5CbGwd5u1k9R8UOnMltwNTcAxoPNOnwjZxObsC7kOL_XSqob05jdrIDgFGM831dM5E4bXQmGGA30i8ER4z-m51YjIcUrkD3zdA-tlup58Oupwb94d1TszBeMDB4LgRdPxXvW_F7TTH20Q/s1600/Solar-Eclipse-from-Space-03.jpg" imageanchor="1"><img alt="solar eclipse earth" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5CbGwd5u1k9R8UOnMltwNTcAxoPNOnwjZxObsC7kOL_XSqob05jdrIDgFGM831dM5E4bXQmGGA30i8ER4z-m51YjIcUrkD3zdA-tlup58Oupwb94d1TszBeMDB4LgRdPxXvW_F7TTH20Q/s320/Solar-Eclipse-from-Space-03.jpg" title="" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnxJvcB794Pmv9VRXZzuR-reBHVOrYGX9ykqD7bkGNs75TuF_eQDeA5bKNJr5TZjDzRL9-0Nv7tat8MIEDoXn141EfYP2CeBjj5Tt9omZIqsJDcsbrCNbkHYliAgeg7sLYcC2PXNi3h3g1/s1600/Solar-Eclipse-from-Space-04.jpg" imageanchor="1"><img alt="solar eclipse" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnxJvcB794Pmv9VRXZzuR-reBHVOrYGX9ykqD7bkGNs75TuF_eQDeA5bKNJr5TZjDzRL9-0Nv7tat8MIEDoXn141EfYP2CeBjj5Tt9omZIqsJDcsbrCNbkHYliAgeg7sLYcC2PXNi3h3g1/s320/Solar-Eclipse-from-Space-04.jpg" title="" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLJU_2Ib43MoeSMdi-TN_O5RfvZFCzTUrRuFU0kfXkeff4BvYjKMfPc1dxzlvu8O_UO0li7z0VwmzDpvdM6x289hVAN2RfMUW14o8OjI0aKrA97ae7Q1_LQmBfJMVJ_9W5B6vD7Xy-8VfV/s1600/Solar-Eclipse-from-Space-05.jpg" imageanchor="1"><img alt="solar eclipse from orbit" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLJU_2Ib43MoeSMdi-TN_O5RfvZFCzTUrRuFU0kfXkeff4BvYjKMfPc1dxzlvu8O_UO0li7z0VwmzDpvdM6x289hVAN2RfMUW14o8OjI0aKrA97ae7Q1_LQmBfJMVJ_9W5B6vD7Xy-8VfV/s320/Solar-Eclipse-from-Space-05.jpg" title="" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJSoVFcUnkSRkTjRRzbT4TtQPRIVzemHJ6Aht_vxgqK33uqZ3K5T6NznORi46o42GqrQkfrLXkthlT7rLkY-AQB85idJb2lDoiOxJVlBCIguTpP0XHM8B9WjJXR_xTzw6Gv-41QqXC-uOK/s1600/Solar-Eclipse-from-Space-06.jpg" imageanchor="1"><img alt="solar eclipse from satelite" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJSoVFcUnkSRkTjRRzbT4TtQPRIVzemHJ6Aht_vxgqK33uqZ3K5T6NznORi46o42GqrQkfrLXkthlT7rLkY-AQB85idJb2lDoiOxJVlBCIguTpP0XHM8B9WjJXR_xTzw6Gv-41QqXC-uOK/s320/Solar-Eclipse-from-Space-06.jpg" title="" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyyOvA9BdeNhsSGKM_Sy1W_ZyaHtTBNypvQfPbBGUepYYl9unEhxDDCeU6_lnF5wKIOaQK_Qkq_opll1SN5eY3mmbMGtxjONcIazgm10I2fXdCK8Z3eFycQpADZJnNQJ9l-yunbWwaB1vg/s1600/Solar-Eclipse-from-Space-07.jpg" imageanchor="1"><img alt="solar eclipse from space" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyyOvA9BdeNhsSGKM_Sy1W_ZyaHtTBNypvQfPbBGUepYYl9unEhxDDCeU6_lnF5wKIOaQK_Qkq_opll1SN5eY3mmbMGtxjONcIazgm10I2fXdCK8Z3eFycQpADZJnNQJ9l-yunbWwaB1vg/s320/Solar-Eclipse-from-Space-07.jpg" title="" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8Ph7rsyhX6xRxy2iyIZ18INhTxq2Fx2dJDV2x1RSF1IcIZR3LaOGFqvlaH7a98fScGBjMoZEvXTk_kSRYcCNXtvZOnSi9i7VXGEwTPppXCN8uGajCc-DA_KhMGu72Xq47bZmQUay0n_He/s1600/Solar-Eclipse-from-Space-08.jpg" imageanchor="1"><img alt="solar eclipse" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8Ph7rsyhX6xRxy2iyIZ18INhTxq2Fx2dJDV2x1RSF1IcIZR3LaOGFqvlaH7a98fScGBjMoZEvXTk_kSRYcCNXtvZOnSi9i7VXGEwTPppXCN8uGajCc-DA_KhMGu72Xq47bZmQUay0n_He/s320/Solar-Eclipse-from-Space-08.jpg" title="" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcR6FnMCGdJCxbUY-K0OJUwT1_LdYh3oA3P3a-Fu__3DHAQ3X11ydTCYtclSYQwF1Hh_doUilyBluPRiWamxWsNmGb7aTc0nkbUrZJYiZfM1NfnPjgW23typASwzqIR79KyNfsCP1lgCZN/s1600/Solar-Eclipse-from-Space-09.jpg" imageanchor="1"><img alt="solar eclipse from space" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcR6FnMCGdJCxbUY-K0OJUwT1_LdYh3oA3P3a-Fu__3DHAQ3X11ydTCYtclSYQwF1Hh_doUilyBluPRiWamxWsNmGb7aTc0nkbUrZJYiZfM1NfnPjgW23typASwzqIR79KyNfsCP1lgCZN/s320/Solar-Eclipse-from-Space-09.jpg" title="" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSgxtAuSbEInMbfEgh83-kzXg6y4u-xE2_6IlPyN2uobBa6muLmNCfnnf1lYn2glUiU3wsA6r898dBFw8fY9WwgpPRxalU4fO2o7sEfQJUC2XmFOkXZDVB3uNXBmzAqJZfYGGLvd7NAUu0/s1600/Solar-Eclipse-from-Space-10.jpg" imageanchor="1"><img alt="solar eclipse space" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSgxtAuSbEInMbfEgh83-kzXg6y4u-xE2_6IlPyN2uobBa6muLmNCfnnf1lYn2glUiU3wsA6r898dBFw8fY9WwgpPRxalU4fO2o7sEfQJUC2XmFOkXZDVB3uNXBmzAqJZfYGGLvd7NAUu0/s320/Solar-Eclipse-from-Space-10.jpg" title="" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8ZIrmm9wFgj0BH2TqOJm3zAbzbDjeF3SQ-kyOZBi2JE2zDBwRyxvHIhiIcoNwpmXhyphenhyphenk-iwEq1nfMTY9X1-l6gV_wJDxbzi6cHDdnsXlakHbw6qHMPnLuJNrxUyFkx9eFo5n08X9-jugwG/s1600/Solar-Eclipse-from-Space-11.jpg" imageanchor="1"><img alt="solar eclipse" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8ZIrmm9wFgj0BH2TqOJm3zAbzbDjeF3SQ-kyOZBi2JE2zDBwRyxvHIhiIcoNwpmXhyphenhyphenk-iwEq1nfMTY9X1-l6gV_wJDxbzi6cHDdnsXlakHbw6qHMPnLuJNrxUyFkx9eFo5n08X9-jugwG/s320/Solar-Eclipse-from-Space-11.jpg" title="" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbg9gjS4TdlnCmhqc3qP5R4ribJoW6m3D-zSnSm4N5Yf9HXlYzpbReirdFZTGD8Do81E_NR0_yNkaamwIEAJ6hyXzDU9tR7aYkCk3pPkB6Y-JDuFJvQ0IbCKMMFExPMD6Ui9uaQ-yPaizB/s1600/Solar-Eclipse-from-Space-12.jpg" imageanchor="1"><img alt="solar eclipse from space" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbg9gjS4TdlnCmhqc3qP5R4ribJoW6m3D-zSnSm4N5Yf9HXlYzpbReirdFZTGD8Do81E_NR0_yNkaamwIEAJ6hyXzDU9tR7aYkCk3pPkB6Y-JDuFJvQ0IbCKMMFExPMD6Ui9uaQ-yPaizB/s320/Solar-Eclipse-from-Space-12.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">DSCOVR, 1 million miles from Earth</div><div style="text-align: center;">March 9, 2016</div><br />Image Credit: DSCOVR EPIC team. NASA Earth Observatory

Solar Eclipse seen by DSCOVR Observatory

DSCOVR, 1 million miles from Earth March 9, 2016 Image Credit: DSCOVR EPIC team. NASA Earth Observatory

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Aurora seen from the International Space Station

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhhAxRC2wmfKjuFkw1sEKKl23oz3MujLQiXlZarh0LeWeB7-Cxv77W2kshPl8otnvRPCPpGSB-3h2wlTtVjhK3_gei57CX1nQGtxsaRt-PWDziGtYRlUGGGUv9tQQzxw5gVyixj1LfbcpQM/s1600/aurora-from-iss.gif" imageanchor="1"><img alt="aurora from iss" border="0" height="223" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhhAxRC2wmfKjuFkw1sEKKl23oz3MujLQiXlZarh0LeWeB7-Cxv77W2kshPl8otnvRPCPpGSB-3h2wlTtVjhK3_gei57CX1nQGtxsaRt-PWDziGtYRlUGGGUv9tQQzxw5gVyixj1LfbcpQM/s400/aurora-from-iss.gif" title="" width="400" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">ISS, Orbit of the Earth</div><br />Video Credit: ESA/NASA

Aurora seen from the International Space Station

ISS, Orbit of the Earth Video Credit: ESA/NASA

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Messier 71: an unusual globular cluster

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXxXxKeyCt-Tl6T6t5GYOSWrpGYPRZVNPYiZ2MAfHxvsI8bOfNJZjA1bO3eYkBdmvX40WIYzzp_IHY8KeJkhgffP7-9y0EGjIMSJnKZq78hEWwWory1f9gbXjcpj6S9-oPLaz2aX1PyOuF/s1600/globular-cluster-Messier-71.jpg" imageanchor="1"><img alt="globular cluster Messier 71" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXxXxKeyCt-Tl6T6t5GYOSWrpGYPRZVNPYiZ2MAfHxvsI8bOfNJZjA1bO3eYkBdmvX40WIYzzp_IHY8KeJkhgffP7-9y0EGjIMSJnKZq78hEWwWory1f9gbXjcpj6S9-oPLaz2aX1PyOuF/s640/globular-cluster-Messier-71.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">This spectacular NASA/ESA Hubble Space Telescope image shows a bright scattering of stars in the small constellation of Sagitta (the Arrow). This is the centre of the globular cluster Messier 71, a great ball of ancient stars on the edge of our galaxy around 13 000 light-years from Earth. M71 is around 27 light-years across.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Globular clusters are like galactic suburbs, pockets of stars that exist on the edge of major galaxies. These clusters are tightly bound together by their gravitational attraction, hence their spherical shape and their name: globulusmeans “little sphere” in Latin.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Around 150 such globular clusters are known to exist around our Milky Way, each one of them containing several hundred thousand stars.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Messier 71 has been known for a long time, having been first spotted in the mid eighteenth century by Swiss astronomer Jean-Philippe de Cheseaux. Cheseaux discovered a number of nebulae in his career, and also spent much time studying religion: one posthumously published work attempted to derive the exact date of Christ’s crucifixion from astronomical events noted in the Bible.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Despite being a familiar object, Messier 71’s precise nature was disputed until recently. Was it simply an open cluster, a loosely bound group of stars? This was for many years the dominant view. But in the 1970s, astronomers came to the view that it is in fact a relatively sparse globular cluster.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The stars in Messier 71, as is usual in such clusters, are relatively old, at around 9 to 10 billion years, and consequently are low in elements other than hydrogen and helium.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">This picture was created from images taken with the Wide Field Channel of the Advanced Camera for Surveys on Hubble. It is a combination of images taken through yellow (F606W — coloured blue) and near-infrared (F814W — coloured red) filters. The exposure times were 304 s and 324 s respectively. The field of view is about 3.4 arcminutes across.</div><br />Image Credit: ESA/Hubble and NASA<br />Explanation from: https://www.spacetelescope.org/images/potw1018a/

Messier 71: an unusual globular cluster

This spectacular NASA/ESA Hubble Space Telescope image shows a bright scattering of stars in the small constellation of Sagitta (the Arrow)....

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Comparison of the Earth to Mercury

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicCv6Rxz7HnBz1Sz83obD12wdKwaYR4798uu7nEVhVXfuR-1rKLtgkB0a61vq8QKWClUixnHvq-e1SU98xPDOvool4sIQ71q9-OCbBdVPp1cjAVh-SuR6Is2WHmPUHGcnqJVq6z7_kq2r4/s1600/Comparison-of-the-Earth-to-Mercury.jpg" imageanchor="1"><img alt="Comparison of the Earth to Mercury" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicCv6Rxz7HnBz1Sz83obD12wdKwaYR4798uu7nEVhVXfuR-1rKLtgkB0a61vq8QKWClUixnHvq-e1SU98xPDOvool4sIQ71q9-OCbBdVPp1cjAVh-SuR6Is2WHmPUHGcnqJVq6z7_kq2r4/s640/Comparison-of-the-Earth-to-Mercury.jpg" title="" /></a></div><br /><div style="text-align: center;"><span style="font-family: "georgia" , "times new roman" , serif; font-size: x-large;">The Earth</span></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to harbor life.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">According to evidence from radiometric dating and other sources, Earth was formed about 4.54 billion years ago. Earth gravitationally interacts with other objects in space, especially the Sun and the Moon. During one orbit around the Sun, Earth rotates about its own axis 366.26 times, creating 365.26 solar days or one sidereal year. Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). The Moon is Earth's only permanent natural satellite. Its gravitational interaction with Earth causes ocean tides, stabilizes the orientation of Earth's rotational axis, and gradually slows Earth's rotational rate.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. 71% of Earth's surface is covered with water, with the remainder consisting of continents and islands that together have many lakes and other sources of water that contribute to the hydrosphere. Earth's polar regions are mostly covered with ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the magnetic field, and a convecting mantle that drives plate tectonics.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Within its first billion years, life appeared in Earth's oceans and began to affect its atmosphere and surface, promoting the proliferation of aerobic as well as anaerobic organisms. Since then, the combination of Earth's distance from the Sun, its physical properties and its geological history have allowed life to thrive and evolve. The earliest undisputed life on Earth arose at least 3.5 billion years ago. Earlier physical evidence of life includes biogenic graphite in 3.7 billion-year-old metasedimentary rocks discovered in southwestern Greenland, as well as "remains of biotic life" found in 4.1 billion-year-old rocks in Western Australia. Earth's biodiversity has expanded continually except when interrupted by mass extinctions. Although scholars estimate that over 99% of all species of life (over five billion) that ever lived on Earth are extinct, there are still an estimated 10–14 million extant species, of which about 1.2 million have been documented and over 86% have not yet been described. Over 7.3 billion humans live on Earth and depend on its biosphere and minerals for their survival. Earth's human population is divided among about two hundred sovereign states which interact through diplomacy, conflict, travel, trade and communication media.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><br /></div><div style="text-align: center;"><span style="font-family: "georgia" , "times new roman" , serif; font-size: x-large;">Mercury</span></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Mercury is the smallest planet in the Solar System and the one closest to the Sun, with an orbital period of about 88 Earth days, which is much faster than any other planet in the Solar System. Seen from Earth, it appears to move around its orbit in about 116 days. It has no known natural satellites. It is named after the Roman deity Mercury, the messenger to the gods.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Partly because it has almost no atmosphere to retain heat, Mercury's surface temperature varies diurnally more than any other planet in the Solar System, ranging from 100 K (−173 °C; −280 °F) at night to 700 K (427 °C; 800 °F) during the day in some equatorial regions. The poles are constantly below 180 K (−93 °C; −136 °F). Mercury's axis has the smallest tilt of any of the Solar System's planets (about 1⁄30 of a degree). However, Mercury's orbital eccentricity is the largest of all known planets in the Solar System. At aphelion, Mercury is about 1.5 times as far from the Sun as it is at perihelion. Mercury's surface is heavily cratered and similar in appearance to the Moon, indicating that it has been geologically inactive for billions of years.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Mercury is tidally or gravitationally locked with the Sun in a 3:2 resonance, and rotates in a way that is unique in the Solar System. As seen relative to the fixed stars, it rotates on its axis exactly three times for every two revolutions it makes around the Sun. As seen from the Sun, in a frame of reference that rotates with the orbital motion, it appears to rotate only once every two Mercurian years. An observer on Mercury would therefore see only one day every two years.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Because Mercury orbits the Sun within Earth's orbit (as does Venus), it can appear in Earth's sky in the morning or the evening, but not in the middle of the night. Also, like Venus and the Moon, it displays a complete range of phases as it moves around its orbit relative to Earth. Although Mercury can appear as a bright object when viewed from Earth, its proximity to the Sun makes it more difficult to see than Venus. Two spacecraft have visited Mercury: Mariner 10 flew by in the 1970s; and MESSENGER, launched in 2004, orbited Mercury over 4,000 times in four years, before exhausting its fuel and crashing into the planet's surface on April 30, 2015.</div><br />Explanation from: https://en.wikipedia.org/wiki/Earth and https://en.wikipedia.org/wiki/Mercury

Comparison of the Earth to Mercury

The Earth Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrest...

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V1331 Cyg

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOTye5DEFouGyVGX5bhAd6UNwPGRp-ebLRDkpYEt0XiR96-wAhuR0N_DmX8-fsGhZyDsR_n7Q8PRnfZwv1Xpo9LhO2j0ImUoipL_nWFqDDhKISC_3yo4smShmc9YtxenEXIsmdZquUhr2K/s1600/V1331-Cyg.jpg" imageanchor="1"><img alt="V1331 Cyg" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOTye5DEFouGyVGX5bhAd6UNwPGRp-ebLRDkpYEt0XiR96-wAhuR0N_DmX8-fsGhZyDsR_n7Q8PRnfZwv1Xpo9LhO2j0ImUoipL_nWFqDDhKISC_3yo4smShmc9YtxenEXIsmdZquUhr2K/s640/V1331-Cyg.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">With its helical appearance resembling a snail’s shell, this reflection nebula seems to spiral out from a luminous central star in this NASA/ESA Hubble Space Telescope image.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The star in the centre, known as V1331 Cyg and located in the dark cloud LDN 981 — or, more commonly, Lynds 981 — had previously been defined as a T Tauri star. A T Tauri is a young star — or Young Stellar Object — that is starting to contract to become a main sequence star similar to the Sun.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">What makes V1331Cyg special is the fact that we look almost exactly at one of its poles. Usually, the view of a young star is obscured by the dust from the circumstellar disc and the envelope that surround it. However, with V1331Cyg we are actually looking in the exact direction of a jet driven by the star that is clearing the dust and giving us this magnificent view.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">This view provides an almost undisturbed view of the star and its immediate surroundings allowing astronomers to study it in greater detail and look for features that might suggest the formation of a very low-mass object in the outer circumstellar disc.</div><br />Image Credit: ESA/Hubble, NASA, Karl Stapelfeldt (GSFC), B. Stecklum and A. Choudhary (Thüringer Landessternwarte Tautenburg, Germany)<br />Explanation from: http://www.spacetelescope.org/images/potw1509a/

V1331 Cyg

With its helical appearance resembling a snail’s shell, this reflection nebula seems to spiral out from a luminous central star in this NASA...

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The Dumbbell Nebula

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjIWE37Nz8cgcFzHWtXeFVWgD3wU0b9egAgLeHtcEqUkmXKebuujzkWdysOJ08oYoNDozmsjlgh1mzkftyIm8Mfz0XbpGjwjsrIjst5-C48tnumQa5oZP9N0A10pEBH8akxS7vnpvCxu1K/s1600/Dumbbell-Nebula.jpg" imageanchor="1"><img alt="Dumbbell Nebula" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjIWE37Nz8cgcFzHWtXeFVWgD3wU0b9egAgLeHtcEqUkmXKebuujzkWdysOJ08oYoNDozmsjlgh1mzkftyIm8Mfz0XbpGjwjsrIjst5-C48tnumQa5oZP9N0A10pEBH8akxS7vnpvCxu1K/s640/Dumbbell-Nebula.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">The Dumbbell Nebula ­— also known as Messier 27 or NGC 6853 — is a typical planetary nebula and is located in the constellation Vulpecula (The Fox). The distance is rather uncertain, but is believed to be around 1,200 light-years. It was first described by the French astronomer and comet hunter Charles Messier who found it in 1764 and included it as no. 27 in his famous list of extended sky objects [2] .Despite its class, the Dumbbell Nebula has nothing to do with planets. It consists of very rarified gas that has been ejected from the hot central star (well visible on this photo), now in one of the last evolutionary stages. The gas atoms in the nebula are excited (heated) by the intense ultraviolet radiation from this star and emit strongly at specific wavelengths.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">This image is the beautiful by-product of a technical test of some FORS1 narrow-band optical interference filtres. They only allow light in a small wavelength range to pass and are used to isolate emissions from particular atoms and ions. In this three-colour composite, a short exposure was first made through a wide-band filtre registering blue light from the nebula. It was then combined with exposures through two interference filtres in the light of double-ionized oxygen atoms and atomic hydrogen. They were colour-coded as “blue”, “green” and “red”, respectively, and then combined to produce this picture that shows the structure of the nebula in “approximately true” colours.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">They are three-colour composite based on two interference ([OIII] at 501 nm and 6 nm FWHM — 5 min exposure time; H-alpha at 656 nm and 6 nm FWHM — 5 min) and one broadband (Bessell B at 429 nm and 88 nm FWHM; 30 sec) filtre images, obtained on September 28, 1998, during mediocre seeing conditions (0.8 arcsec). The CCD camera has 2048 x 2048 pixels, each covering 24 x 24 µm and the sky fields shown measure 6.8 x 6.8 arcminutes and 3.5 x 3.9 arcminutes, respectively. North is up; East is left.</div><br />Image Credit: ESO<br />Explanation from:https://www.eso.org/public/images/eso9846a/

The Dumbbell Nebula

The Dumbbell Nebula ­— also known as Messier 27 or NGC 6853 — is a typical planetary nebula and is located in the constellation Vulpecula (T...

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Hubble image of star cluster Messier 15

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcjWIYcOmKxK_HstJwlH_ItuObeAQLvx52PXNjGmGiKIRXxaxU95U7acDBXcbORgANiPiS0_eVJhMCHG99helW9RfsmJ4wR8MiKxMeWGcP82hmRk8xR57t_qUeBuS0cmwO9X5OcfLHS6O1/s1600/star-cluster-Messier-15.jpg" imageanchor="1"><img alt="star cluster Messier 15" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcjWIYcOmKxK_HstJwlH_ItuObeAQLvx52PXNjGmGiKIRXxaxU95U7acDBXcbORgANiPiS0_eVJhMCHG99helW9RfsmJ4wR8MiKxMeWGcP82hmRk8xR57t_qUeBuS0cmwO9X5OcfLHS6O1/s640/star-cluster-Messier-15.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">This cluster of stars is known as Messier 15, and is located some 35 000 light-years away in the constellation of Pegasus (The Winged Horse). It is one of the oldest globular clusters known, with an age of around 12 billion years.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Both very hot blue stars and cooler golden stars can be seen swarming together in the image, becoming more concentrated towards the cluster's bright centre. Messier 15 is one of the densest globular clusters known, with most of its mass concentrated at its core. As well as stars, Messier 15 was the first cluster known to host a planetary nebula, and it has been found to have a rare type of black hole at its centre.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">This image is made up of observations from Hubble's Wide Field Camera 3 and Advanced Camera for Surveys in the ultraviolet, infrared, and optical parts of the spectrum.</div><br />Image Credit: NASA, ESA<br />Explanation from: https://www.spacetelescope.org/images/heic1321a/<br /><div></div>

Hubble image of star cluster Messier 15

This cluster of stars is known as Messier 15, and is located some 35 000 light-years away in the constellation of Pegasus (The Winged Horse)...

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Calbuco Volcano Eruption

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSPTnafguGFW6nsDpZpOvXptcsmBURtV6CNDL6lHmsXXXnBF_E8YXAmmoRY-HLg2lwE-uYvvoZUud8VCkKejxLKrOqkyxN1-_Rp0pmF4NTqdz_IyGuxp9X5dJJUpAHAsj-vMWXLWoO8A36/s1600/Calbuco-Volcano-Eruption.gif" imageanchor="1"><img alt="Calbuco Volcano Eruption" border="0" height="223" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSPTnafguGFW6nsDpZpOvXptcsmBURtV6CNDL6lHmsXXXnBF_E8YXAmmoRY-HLg2lwE-uYvvoZUud8VCkKejxLKrOqkyxN1-_Rp0pmF4NTqdz_IyGuxp9X5dJJUpAHAsj-vMWXLWoO8A36/s400/Calbuco-Volcano-Eruption.gif" title="" width="400" /></a></div><div><div style="text-align: center;"><br /></div></div><div style="text-align: center;">Puerto Varas, Chile</div><div style="text-align: center;">April 22, 2015</div><br />Video Credit & Copyright: Rodrigo Barrera

Calbuco Volcano Eruption

Puerto Varas, Chile April 22, 2015 Video Credit & Copyright: Rodrigo Barrera

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Panorama of the Milky Way Galaxy above Mt Barney during a massive fire

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEn67JzwCavu6RZgj6PbY0wgglBFDmYqS5Nuc1AKrvrZoBDSP9uZEjEGQc_fE8uTPZKLd_f7QbjzTa7a3CSac2nweDkpJkhIIT2DMT6xpD1cZ9011frAL1ncqnxqRvkg5U2WmbRQOehyCY/s1600/milky-way-panaroma.jpg" imageanchor="1"><img alt="Panorama of the Milky Way Galaxy above Mt Barney during a massive fire" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEn67JzwCavu6RZgj6PbY0wgglBFDmYqS5Nuc1AKrvrZoBDSP9uZEjEGQc_fE8uTPZKLd_f7QbjzTa7a3CSac2nweDkpJkhIIT2DMT6xpD1cZ9011frAL1ncqnxqRvkg5U2WmbRQOehyCY/s640/milky-way-panaroma.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Scenic Rim Region in Queensland, Australia</div><div style="text-align: center;">September 23, 2013</div><br />Image Credit & Copyright: Rob Packer<br /><div></div>

Panorama of the Milky Way Galaxy above Mt Barney during a massive fire

Scenic Rim Region in Queensland, Australia September 23, 2013 Image Credit & Copyright: Rob Packer

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NGC 2683: The UFO Galaxy

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0LJWT1_53tkZXLd2_kRB9M_7O6K7xZg4eqh2n62ahdrJARDO7yIe54rcbpyCh56aiSscHq4kwbv_TFQ94cDj8KPRfywc2hu2bl4FSSCNPXsgri3-N3ybXWjLYRSCifCaKslNWA5p7tAEn/s1600/NGC-2683.jpg" imageanchor="1"><img alt="NGC 2683" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0LJWT1_53tkZXLd2_kRB9M_7O6K7xZg4eqh2n62ahdrJARDO7yIe54rcbpyCh56aiSscHq4kwbv_TFQ94cDj8KPRfywc2hu2bl4FSSCNPXsgri3-N3ybXWjLYRSCifCaKslNWA5p7tAEn/s640/NGC-2683.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">The NASA/ESA Hubble Space Telescope has spotted a UFO — well, the UFO Galaxy, to be precise. NGC 2683 is a spiral galaxy seen almost edge-on, giving it the shape of a classic science fiction spaceship. This is why the astronomers at the Astronaut Memorial Planetarium and Observatory gave it this attention-grabbing nickname.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">While a bird’s eye view lets us see the detailed structure of a galaxy, a side-on view has its own perks. In particular, it gives astronomers a great opportunity to see the delicate dusty lanes of the spiral arms silhouetted against the golden haze of the galaxy’s core. In addition, brilliant clusters of young blue stars shine scattered throughout the disc, mapping the galaxy’s star-forming regions.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Perhaps surprisingly, side-on views of galaxies like this one do not prevent astronomers from deducing their structures. Studies of the properties of the light coming from NGC 2683 suggest that this is a barred spiral galaxy, even though the angle we see it at does not let us see this directly.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">NGC 2683, discovered on 5 February 1788 by the famous astronomer William Herschel, lies in the Northern constellation of Lynx. A constellation named not because of its resemblance to the feline animal, but because it is fairly faint, requiring the “sensitive eyes of a cat” to discern it. And when you manage to get a look at it, you’ll find treasures like this, making it well worth the effort.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">This image is produced from two adjacent fields observed in visible and infrared light by Hubble’s Advanced Camera for Surveys. A narrow strip which appears slightly blurred and crosses most the image horizontally is a result of a gap between Hubble’s detectors. This strip has been patched using images from observations of the galaxy made by ground-based telescopes, which show significantly less detail.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The field of view is approximately 6.5 by 3.3 arcminutes.</div><br />Image Credit: ESA/Hubble & NASA<br />Explanation from: https://www.spacetelescope.org/images/potw1213a/

NGC 2683: The UFO Galaxy

The NASA/ESA Hubble Space Telescope has spotted a UFO — well, the UFO Galaxy, to be precise. NGC 2683 is a spiral galaxy seen almost edge-on...

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2012 Total Solar Eclipse seen from Australia

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJdkJqPbTDqH_Br01TnNaplv_Fr-1hi4R_EwgVpaJToMS53r4xQWm64MYIGA75NjIR_0WP89oAmXVIkI12GHvsmRQLGB5a-5m7NM9W5p1HcAHvxEWZqMWON0NDubpFoZT_8VbrgsvOp8il/s1600/Total-Solar-Eclipse.gif" imageanchor="1"><img alt="Total Solar Eclipse" border="0" height="358" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJdkJqPbTDqH_Br01TnNaplv_Fr-1hi4R_EwgVpaJToMS53r4xQWm64MYIGA75NjIR_0WP89oAmXVIkI12GHvsmRQLGB5a-5m7NM9W5p1HcAHvxEWZqMWON0NDubpFoZT_8VbrgsvOp8il/s640/Total-Solar-Eclipse.gif" title="" width="640" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Granite, Australia</div><div style="text-align: center;">November 14, 2012</div><br />Video Credit & Copyright: Colin Legg<br /><div></div>

2012 Total Solar Eclipse seen from Australia

Granite, Australia November 14, 2012 Video Credit & Copyright: Colin Legg

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Quadruple star system DI Cha

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVhHrz1Uj1nkkTGVLaEkVplrDNgFmBDilmaGYDhAZ0WrNu03vVskHA5s41inFMcMT-dPDZ9R82PJ_2hPJxuhfp56SRyLtCRAO7DrZPngApv-pevbeqiy3BuVmWlLLSDBAeeL81FhxNWhJJ/s1600/DI-Cha-star.jpg" imageanchor="1"><img alt="DI Cha" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVhHrz1Uj1nkkTGVLaEkVplrDNgFmBDilmaGYDhAZ0WrNu03vVskHA5s41inFMcMT-dPDZ9R82PJ_2hPJxuhfp56SRyLtCRAO7DrZPngApv-pevbeqiy3BuVmWlLLSDBAeeL81FhxNWhJJ/s640/DI-Cha-star.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Two stars shine through the centre of a ring of cascading dust in this image taken by the NASA/ESA Hubble Space Telescope. The star system is named DI Cha, and while only two stars are apparent, it is actually a quadruple system containing two sets of binary stars.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">As this is a relatively young star system it is surrounded by dust. The young stars are moulding the dust into a wispy wrap.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The host of this alluring interaction between dust and star is the Chamaeleon I dark cloud — one of three such clouds that comprise a large star-forming region known as the Chamaeleon Complex. DI Cha's juvenility is not remarkable within this region. In fact, the entire system is among not only the youngest but also the closest collections of newly formed stars to be found and so provides an ideal target for studies of star formation.</div><br />Image Credit: ESA/Hubble & NASA, Judy Schmidt<br />Explanation from: http://www.spacetelescope.org/images/potw1543a/

Quadruple star system DI Cha

Two stars shine through the centre of a ring of cascading dust in this image taken by the NASA/ESA Hubble Space Telescope. The star system i...

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Ant-like Space Structure Previews Death of Our Sun

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDRETGlJ0gOWYRE31oOHm-Qzmb2RRg95sbYNB2PYZ14jvD2X2_b4vs7Hi1VFaackeYHr4nhkGw4E4fr6K7nG_G1DOpx9tt0Z_BCy7YxID_85V39DBAwds8BCerKakjglB5bCqDIKaTls3s/s1600/Ant-Nebula.jpg" imageanchor="1"><img alt="Ant Nebula" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDRETGlJ0gOWYRE31oOHm-Qzmb2RRg95sbYNB2PYZ14jvD2X2_b4vs7Hi1VFaackeYHr4nhkGw4E4fr6K7nG_G1DOpx9tt0Z_BCy7YxID_85V39DBAwds8BCerKakjglB5bCqDIKaTls3s/s640/Ant-Nebula.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">From ground-based telescopes, the so-called "ant nebula" (Menzel 3, or Mz 3) resembles the head and thorax of a garden-variety ant. This dramatic NASA/ESA Hubble Space Telescope image, showing 10 times more detail, reveals the "ant's" body as a pair of fiery lobes protruding from a dying, Sun-like star.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The Hubble images directly challenge old ideas about the last stages in the lives of stars. By observing Sun-like stars as they approach their deaths, the Hubble Heritage image of Mz 3 — along with pictures of other planetary nebulae — shows that our Sun's fate probably will be more interesting, complex, and striking than astronomers imagined just a few years ago.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Though approaching the violence of an explosion, the ejection of gas from the dying star at the center of Mz 3 has intriguing symmetrical patterns unlike the chaotic patterns expected from an ordinary explosion. Scientists using Hubble would like to understand how a spherical star can produce such prominent, non-spherical symmetries in the gas that it ejects.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">One possibility is that the central star of Mz 3 has a closely orbiting companion that exerts strong gravitational tidal forces, which shape the outflowing gas. For this to work, the orbiting companion star would have to be close to the dying star, about the distance of the Earth from the Sun. At that distance the orbiting companion star wouldn't be far outside the hugely bloated hulk of the dying star. It's even possible that the dying star has consumed its companion, which now orbits inside of it, much like the duck in the wolf's belly in the story "Peter and the Wolf."</div><div style="text-align: center;"><br /></div><div style="text-align: center;">A second possibility is that, as the dying star spins, its strong magnetic fields are wound up into complex shapes like spaghetti in an eggbeater. Charged winds moving at speeds up to 1000 kilometers per second from the star, much like those in our Sun's solar wind but millions of times denser, are able to follow the twisted field lines on their way out into space. These dense winds can be rendered visible by ultraviolet light from the hot central star or from highly supersonic collisions with the ambient gas that excites the material into florescence.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">No other planetary nebula observed by Hubble resembles Mz 3 very closely. M2-9 comes close, but the outflow speeds in Mz 3 are up to 10 times larger than those of M2-9. Interestingly, the very massive, young star, Eta Carinae, shows a very similar outflow pattern.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Astronomers Bruce Balick (University of Washington) and Vincent Icke (Leiden University) used Hubble to observe this planetary nebula, Mz 3, in July 1997 with the Wide Field Planetary Camera 2. One year later, astronomers Raghvendra Sahai and John Trauger of the Jet Propulsion Lab in California snapped pictures of Mz 3 using slightly different filters. This intriguing image, which is a composite of several filters from each of the two datasets, was created by the Hubble Heritage Team.</div><br />Image Credit: NASA, ESA and The Hubble Heritage Team (STScI/AURA)<br />Explanation from: http://hubblesite.org/newscenter/archive/releases/2001/05/image/a/

Ant-like Space Structure Previews Death of Our Sun

From ground-based telescopes, the so-called "ant nebula" (Menzel 3, or Mz 3) resembles the head and thorax of a garden-variety ant...

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NASA, ESA Telescopes find evidence for Asteroid Belt around star Vega

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoMeToUG_QRtasduiDpZAlWlj0264KB8VizgElEVZghCSnXkWBKXcsSS7s9MwMmVGCAf7SIDSFNU1Xv5UT8ME1W0Zzzb-Li8hpWAqmx4oxYKnkyQ7Kvg80BLqN44ZrwR7FXY_zJ2rPBuc1/s1600/asteroid-belt-vega.jpg" imageanchor="1"><img alt="Asteroid Belt around star Vega" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoMeToUG_QRtasduiDpZAlWlj0264KB8VizgElEVZghCSnXkWBKXcsSS7s9MwMmVGCAf7SIDSFNU1Xv5UT8ME1W0Zzzb-Li8hpWAqmx4oxYKnkyQ7Kvg80BLqN44ZrwR7FXY_zJ2rPBuc1/s640/asteroid-belt-vega.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">This artist's concept illustrates an asteroid belt around the bright star Vega. Evidence for this warm ring of debris was found using NASA's Spitzer Space Telescope, and the European Space Agency's Herschel Space Observatory, in which NASA plays an important role. </div><div style="text-align: center;"><br /></div><div style="text-align: center;">Astronomers have discovered what appears to be a large asteroid belt around the star Vega, the second brightest star in northern night skies. The scientists used data from NASA's Spitzer Space Telescope and the European Space Agency's Herschel Space Observatory, in which NASA plays an important role.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The discovery of an asteroid belt-like band of debris around Vega makes the star similar to another observed star called Fomalhaut. The data are consistent with both stars having inner, warm belts and outer, cool belts separated by a gap. This architecture is similar to the asteroid and Kuiper belts in our own Solar System.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">What is maintaining the gap between the warm and cool belts around Vega and Fomalhaut? The results strongly suggest the answer is multiple planets. Our Solar System's asteroid belt, which lies between Mars and Jupiter, is maintained by the gravity of the terrestrial planets and the giant planets, and the outer Kuiper belt is sculpted by the giant planets.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><i>"Our findings echo recent results showing multiple-planet systems are common beyond our sun,"</i> said Kate Su, an astronomer at the Steward Observatory at the University of Arizona, Tucson.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Vega and Fomalhaut are similar in other ways. Both are about twice the mass of our sun and burn a hotter, bluer color in visible light. Both stars are relatively nearby, at about 25 light-years away. The stars are thought to be around 400 million years old, but Vega could be closer to its 600 millionth birthday. Fomalhaut has a single candidate planet orbiting it, Fomalhaut b, which orbits at the inner edge of its cometary belt.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The Herschel and Spitzer telescopes detected infrared light emitted by warm and cold dust in discrete bands around Vega and Fomalhaut, discovering the new asteroid belt around Vega and confirming the existence of the other belts around both stars. Comets and the collisions of rocky chunks replenish the dust in these bands. The inner belts in these systems cannot be seen in visible light because the glare of their stars outshines them.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Both the inner and outer belts contain far more material than our own asteroid and Kuiper belts. The reason is twofold: the star systems are far younger than our own, which has had hundreds of millions more years to clean house, and the systems likely formed from an initially more massive cloud of gas and dust than our Solar System.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The gap between the inner and outer debris belts for Vega and Fomalhaut also proportionally corresponds to the distance between our sun's asteroid and Kuiper belts. This distance works out to a ratio of about 1:10, with the outer belt 10 times farther from its host star than the inner belt. As for the large gap between the two belts, it is likely there are several undetected planets, Jupiter-size or smaller, creating a dust-free zone between the two belts. A good comparison star system is HR 8799, which has four known planets that sweep up the space between two similar disks of debris.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><i>"Overall, the large gap between the warm and the cold belts is a signpost that points to multiple planets likely orbiting around Vega and Fomalhaut,"</i> said Su.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">If unseen planets do, in fact, orbit Vega and Fomalhaut, these bodies will not likely stay hidden.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><i>"Upcoming new facilities such as NASA's James Webb Space Telescope should be able to find the planets,"</i> said paper co-author Karl Stapelfeldt, chief of the Exoplanets and Stellar Astrophysics Laboratory at NASA's Goddard Space Flight Center in Greenbelt, Md.</div><br />Image Credit: NASA/JPL-Caltech<br />Explanation from: http://www.nasa.gov/mission_pages/spitzer/multimedia/pia16610.html and http://www.nasa.gov/mission_pages/spitzer/news/spitzervega20130108.html

NASA, ESA Telescopes find evidence for Asteroid Belt around star Vega

This artist's concept illustrates an asteroid belt around the bright star Vega. Evidence for this warm ring of debris was found using NA...

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Raining Loops on the Sun

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjpoxDNgHBV2Efw8KxJIgyhkqQAEwWI3UPSQN_V5v2n9pthZcCATudyQaap_TgFQKdEskriwXdctJ1eVp8mzAijOow7ulYLliJrMLlqqiF_hj_FURwJq6k8UfuYmWXtgSgeGz7bPFu4dN3/s1600/Coronal-Rain.gif" imageanchor="1"><img alt="Coronal Rain" border="0" height="358" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjpoxDNgHBV2Efw8KxJIgyhkqQAEwWI3UPSQN_V5v2n9pthZcCATudyQaap_TgFQKdEskriwXdctJ1eVp8mzAijOow7ulYLliJrMLlqqiF_hj_FURwJq6k8UfuYmWXtgSgeGz7bPFu4dN3/s640/Coronal-Rain.gif" title="" width="640" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Eruptive events on the Sun can be wildly different. Some come just with a solar flare, some with an additional ejection of solar material called a coronal mass ejection (CME), and some with complex moving structures in association with changes in magnetic field lines that loop up into the Sun's atmosphere, the corona.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">On July 19, 2012, an eruption occurred on the Sun that produced all three. A moderately powerful solar flare exploded on the Sun's lower right limb, sending out light and radiation. Next came a CME, which shot off to the right out into space. And then, the Sun treated viewers to one of its dazzling magnetic displays – a phenomenon known as coronal rain.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Over the course of the next day, hot plasma in the corona cooled and condensed along strong magnetic fields in the region. Magnetic fields, themselves, are invisible, but the charged plasma is forced to move along the lines, showing up brightly in the extreme ultraviolet wavelength of 304 Angstroms, which highlights material at a temperature of about 50,000 Kelvin. This plasma acts as a tracer, helping scientists watch the dance of magnetic fields on the Sun, outlining the fields as it slowly falls back to the solar surface.</div><br />Video Credit: NASA/SDO/NASA Goddard<br />Explanation from:http://www.nasa.gov/mission_pages/sdo/news/coronal-rain.html

Raining Loops on the Sun

Eruptive events on the Sun can be wildly different. Some come just with a solar flare, some with an additional ejection of solar material ca...

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Solar Storms Ignite X-ray "Northern Lights" on Jupiter

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEZchmzD4BRcUj4u-FxO3WqDAZS2f80554vtz-i8rpht2ztmUD08zkYF4FH14iTkfJOcBKWkmc01iThsTqYSW0PbyqKN3RE5iiTo5O-8CykZI9NsY5q7DRIoEUEZbpFyCHDFLXk8cX1LUX/s1600/jupiter-aurora1.jpg" imageanchor="1"><img alt="jupiter aurora" border="0" height="294" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEZchmzD4BRcUj4u-FxO3WqDAZS2f80554vtz-i8rpht2ztmUD08zkYF4FH14iTkfJOcBKWkmc01iThsTqYSW0PbyqKN3RE5iiTo5O-8CykZI9NsY5q7DRIoEUEZbpFyCHDFLXk8cX1LUX/s320/jupiter-aurora1.jpg" title="" width="320" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4v1AH41fJONNiFxY_H9JLxqJ-gAKUepI36plRcOiypLUe_sAH4kcISwWjF4xpDL4ecVQKMlpsBVY2yB88rPrn0EIMy0h4l0LMkB0XdklUux03awQxBtS62ix4tunkOIOD6C9TfWRA4Qsb/s1600/jupiter-aurora2.jpg" imageanchor="1"><img alt="Jupiter Northern Lights" border="0" height="294" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4v1AH41fJONNiFxY_H9JLxqJ-gAKUepI36plRcOiypLUe_sAH4kcISwWjF4xpDL4ecVQKMlpsBVY2yB88rPrn0EIMy0h4l0LMkB0XdklUux03awQxBtS62ix4tunkOIOD6C9TfWRA4Qsb/s320/jupiter-aurora2.jpg" title="" width="320" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Solar storms are triggering X-ray auroras on Jupiter that are about eight times brighter than normal over a large area of the planet and hundreds of times more energetic than Earth’s "northern lights," according to a new study using data from NASA’s Chandra X-ray Observatory. This result is the first time that Jupiter's auroras have been studied in X-ray light when a giant solar storm arrived at the planet.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The Sun constantly ejects streams of particles into space in the solar wind. Sometimes, giant storms, known as coronal mass ejections (CMEs), erupt and the winds become much stronger. These events compress Jupiter's magnetosphere, the region of space controlled by Jupiter's magnetic field, shifting its boundary with the solar wind inward by more than a million miles. This new study found that the interaction at the boundary triggers the X-rays in Jupiter's auroras, which cover an area bigger than the surface of the Earth.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">These composite images show Jupiter and its aurora during and after a CME's arrival at Jupiter in October 2011. In these images, X-ray data from Chandra (purple) have been overlaid on an optical image from the Hubble Space Telescope. The left-hand panel reveals the X-ray activity when the CME reached Jupiter, and the right-hand side is the view two days later after the CME subsided. The impact of the CME on Jupiter's aurora was tracked by monitoring the X-rays emitted during two 11-hour observations. The scientists used that data to pinpoint the source of the X-ray activity and identify areas to investigate further at different time points. They plan to find out how the X-rays form by collecting data on Jupiter's magnetic field, magnetosphere and aurora using Chandra and ESA’s XMM-Newton.</div><br />Image Credit: X-ray: NASA/CXC/UCL/W.Dunn et al, Optical: NASA/STScI<br />Explanation from: https://www.nasa.gov/mission_pages/chandra/solar-storms-ignite-xray-northern-lights-on-jupiter.html

Solar Storms Ignite X-ray "Northern Lights" on Jupiter

Solar storms are triggering X-ray auroras on Jupiter that are about eight times brighter than normal over a large area of the planet and hun...

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Comparison of the Earth to Saturn

<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQ6m6wqtwpO_sJQLdicGn1Cq0WPPXEjqtYDjb3d_O_haoStmx3BjEKPEFSbM-4PZDCfepuhcNYm2D3UI_1o3vqyeuahALJhhcnJ4JRXMrJUJVrMxFI4_70hJGI6ehoO2YLO_0apGlPELIw/s1600/Comparison-of-the-Earth-to-Saturn.jpg" imageanchor="1"><img alt="Comparison of the Earth to Saturn" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQ6m6wqtwpO_sJQLdicGn1Cq0WPPXEjqtYDjb3d_O_haoStmx3BjEKPEFSbM-4PZDCfepuhcNYm2D3UI_1o3vqyeuahALJhhcnJ4JRXMrJUJVrMxFI4_70hJGI6ehoO2YLO_0apGlPELIw/s640/Comparison-of-the-Earth-to-Saturn.jpg" title="" /></a><br /><br /><div style="text-align: center;"><span style="font-family: "georgia" , "times new roman" , serif; font-size: x-large;">The Earth</span></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to harbor life.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">According to evidence from radiometric dating and other sources, Earth was formed about 4.54 billion years ago. Earth gravitationally interacts with other objects in space, especially the Sun and the Moon. During one orbit around the Sun, Earth rotates about its own axis 366.26 times, creating 365.26 solar days or one sidereal year. Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). The Moon is Earth's only permanent natural satellite. Its gravitational interaction with Earth causes ocean tides, stabilizes the orientation of Earth's rotational axis, and gradually slows Earth's rotational rate.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. 71% of Earth's surface is covered with water, with the remainder consisting of continents and islands that together have many lakes and other sources of water that contribute to the hydrosphere. Earth's polar regions are mostly covered with ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the magnetic field, and a convecting mantle that drives plate tectonics.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Within its first billion years, life appeared in Earth's oceans and began to affect its atmosphere and surface, promoting the proliferation of aerobic as well as anaerobic organisms. Since then, the combination of Earth's distance from the Sun, its physical properties and its geological history have allowed life to thrive and evolve. The earliest undisputed life on Earth arose at least 3.5 billion years ago. Earlier physical evidence of life includes biogenic graphite in 3.7 billion-year-old metasedimentary rocks discovered in southwestern Greenland, as well as "remains of biotic life" found in 4.1 billion-year-old rocks in Western Australia. Earth's biodiversity has expanded continually except when interrupted by mass extinctions. Although scholars estimate that over 99% of all species of life (over five billion) that ever lived on Earth are extinct, there are still an estimated 10–14 million extant species, of which about 1.2 million have been documented and over 86% have not yet been described. Over 7.3 billion humans live on Earth and depend on its biosphere and minerals for their survival. Earth's human population is divided among about two hundred sovereign states which interact through diplomacy, conflict, travel, trade and communication media.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><br /></div><div style="text-align: center;"><span style="font-family: "georgia" , "times new roman" , serif; font-size: x-large;">Saturn</span></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius about nine times that of Earth. Although only one-eighth the average density of Earth, with its larger volume Saturn is just over 95 times more massive. Saturn is named after the Roman god of agriculture; its astronomical symbol (♄) represents the god's sickle.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Saturn's interior is probably composed of a core of iron–nickel and rock (silicon and oxygen compounds). This core is surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and finally outside the Frenkel line a gaseous outer layer. Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere. Electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is weaker than Earth's, but has a magnetic moment 580 times that of Earth due to Saturn's larger size. Saturn's magnetic field strength is around one-twentieth of Jupiter's. The outer atmosphere is generally bland and lacking in contrast, although long-lived features can appear. Wind speeds on Saturn can reach 1,800 km/h (500 m/s), higher than on Jupiter, but not as high as those on Neptune.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Saturn has a prominent ring system that consists of nine continuous main rings and three discontinuous arcs and that is composed mostly of ice particles with a smaller amount of rocky debris and dust. Sixty-two moons are known to orbit Saturn, of which fifty-three are officially named. This does not include the hundreds of moonlets comprising the rings. Titan, Saturn's largest moon, and the second-largest in the Solar System, is larger than the planet Mercury, although less massive, and is the only moon in the Solar System to have a substantial atmosphere.</div><br />Explanation from: https://en.wikipedia.org/wiki/Earth and https://en.wikipedia.org/wiki/Saturn

Comparison of the Earth to Saturn

The Earth Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrest...

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Cities at Night seen from the International Space Station

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhp-zQRSc4b6woLQRhJngYQnR9mInqBbbJMlGgBD4DgheH5IAnMmKatkH8_rFG45mpU-TDvIOMfEjX4pXbsgkk8nrT8gjNjsb30ceBFk_xS2MDWzM4yysI9J5kcpHOOQuvzk7v5jjOofQOX/s1600/cities-at-night-from-iss.gif" imageanchor="1"><img alt="Cities at Night from ISS" border="0" height="222" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhp-zQRSc4b6woLQRhJngYQnR9mInqBbbJMlGgBD4DgheH5IAnMmKatkH8_rFG45mpU-TDvIOMfEjX4pXbsgkk8nrT8gjNjsb30ceBFk_xS2MDWzM4yysI9J5kcpHOOQuvzk7v5jjOofQOX/s400/cities-at-night-from-iss.gif" title="" width="400" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">ISS, Orbit of the Earth</div><br />Video Credit: ESA/NASA

Cities at Night seen from the International Space Station

ISS, Orbit of the Earth Video Credit: ESA/NASA

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Lightning Strikes over the Puyehue-Cordón Caulle Volcano

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJ-4cSRG1CIEnAdSLDaIbXZ27VIxxl7fjn9awApJrNjcew_b2FHUxXB_ZjVWW-TLmJxqcwCmRydYPg1V0p0FyvM9dtNMI0IQA-OEUFyGiZtYjTOwMrneGafLHrDIzBoWgpIB6Kw4lsyBrg/s1600/Puyehue-Cordon-Caulle-Volcano.jpg" imageanchor="1"><img alt="Lightning Strikes over the Puyehue-Cordón Caulle Volcano" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJ-4cSRG1CIEnAdSLDaIbXZ27VIxxl7fjn9awApJrNjcew_b2FHUxXB_ZjVWW-TLmJxqcwCmRydYPg1V0p0FyvM9dtNMI0IQA-OEUFyGiZtYjTOwMrneGafLHrDIzBoWgpIB6Kw4lsyBrg/s640/Puyehue-Cordon-Caulle-Volcano.jpg" title="" /></a></div><div><div style="text-align: center;"><br /></div></div><div style="text-align: center;">Puyehue-Cordón Caulle, Chile</div><div style="text-align: center;">June 6, 2011</div><br />Image Credit & Copyright: Francisco Negroni

Lightning Strikes over the Puyehue-Cordón Caulle Volcano

Puyehue-Cordón Caulle, Chile June 6, 2011 Image Credit & Copyright: Francisco Negroni

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Artist's Impression of the surface of Jupiter's Moon Europa

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi178grdPyEaC3T0kbaG0X3y4cA4fiegHP5e7d0Nrvq5Xq4VUYEt7BXmVDLTdMrzTcbIThRGPEqu0yjiI9Mi3vdrV_tn3qtf9v006PUAjDKqI_uaPFpVe6zsKQJp2_Ape-7_FFP3gfyHm7K/s1600/surface-of-europa.jpg" imageanchor="1"><img alt="surface of europa" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi178grdPyEaC3T0kbaG0X3y4cA4fiegHP5e7d0Nrvq5Xq4VUYEt7BXmVDLTdMrzTcbIThRGPEqu0yjiI9Mi3vdrV_tn3qtf9v006PUAjDKqI_uaPFpVe6zsKQJp2_Ape-7_FFP3gfyHm7K/s640/surface-of-europa.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">This artist's concept shows a simulated view from the surface of Jupiter's moon Europa. Europa's potentially rough, icy surface, tinged with reddish areas that scientists hope to learn more about, can be seen in the foreground. The giant planet Jupiter looms over the horizon.</div><br />Image Credit: NASA/JPL-Caltech

Artist's Impression of the surface of Jupiter's Moon Europa

This artist's concept shows a simulated view from the surface of Jupiter's moon Europa. Europa's potentially rough, icy surface,...

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The Planet full of Water: Mars 4 billion years ago

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitsP18XUkAIOgejREqjf6PUdp8YpR0_hNJ1lajYbKz_AUVgSaxJuf-juOaSbYBdLxNQN5brQ53p8fhXzQOEy7X7DxDOA5JaqDrGolRiQRe-AZjSPv8K_M-LD3vZhLSMo2VxViVu5XzKu0Z/s1600/water-on-mars.gif" imageanchor="1"><img alt="Water of Mars" border="0" height="223" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitsP18XUkAIOgejREqjf6PUdp8YpR0_hNJ1lajYbKz_AUVgSaxJuf-juOaSbYBdLxNQN5brQ53p8fhXzQOEy7X7DxDOA5JaqDrGolRiQRe-AZjSPv8K_M-LD3vZhLSMo2VxViVu5XzKu0Z/s400/water-on-mars.gif" title="" width="400" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">This artist’s impression shows how Mars may have looked about four billion years ago. The young planet Mars would have had enough water to cover its entire surface in a liquid layer about 140 metres deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere, and in some regions reaching depths greater than 1.6 kilometres.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">A primitive ocean on Mars held more water than Earth’s Arctic Ocean, and covered a greater portion of the planet’s surface than the Atlantic Ocean does on Earth, according to new results published today. An international team of scientists used ESO’s Very Large Telescope, along with instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility, to monitor the atmosphere of the planet and map out the properties of the water in different parts of Mars’s atmosphere over a six-year period. These new maps are the first of their kind. The results appear online in the journal Science today.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">About four billion years ago, the young planet would have had enough water to cover its entire surface in a liquid layer about 140 metres deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere, and in some regions reaching depths greater than 1.6 kilometres.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><i>“Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space,”</i> said Geronimo Villanueva, a scientist working at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, USA, and lead author of the new paper. <i>“With this work, we can better understand the history of water on Mars.”</i></div><div style="text-align: center;"><br /></div><div style="text-align: center;">The new estimate is based on detailed observations of two slightly different forms of water in Mars’s atmosphere. One is the familiar form of water, made with two hydrogen atoms and one oxygen, H2O. The other is HDO, or semi-heavy water, a naturally occurring variation in which one hydrogen atom is replaced by a heavier form, called deuterium.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">As the deuterated form is heavier than normal water, it is less easily lost into space through evaporation. So, the greater the water loss from the planet, the greater the ratio of HDO to H2O in the water that remains.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The researchers distinguished the chemical signatures of the two types of water using ESO’s Very Large Telescope in Chile, along with instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility in Hawaii. By comparing the ratio of HDO to H2O, scientists can measure by how much the fraction of HDO has increased and thus determine how much water has escaped into space. This in turn allows the amount of water on Mars at earlier times to be estimated.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">In the study, the team mapped the distribution of H2O and HDO repeatedly over nearly six Earth years — equal to about three Mars years — producing global snapshots of each, as well as their ratio. The maps reveal seasonal changes and microclimates, even though modern Mars is essentially a desert.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Ulli Kaeufl of ESO, who was responsible for building one of the instruments used in this study and is a co-author of the new paper, adds: <i>"I am again overwhelmed by how much power there is in remote sensing on other planets using astronomical telescopes: we found an ancient ocean more than 100 million kilometres away!"</i></div><div style="text-align: center;"><br /></div><div style="text-align: center;">The team was especially interested in regions near the north and south poles, because the polar ice caps are the planet’s largest known reservoir of water. The water stored there is thought to document the evolution of Mars’s water from the wet Noachian period, which ended about 3.7 billion years ago, to the present.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The new results show that atmospheric water in the near-polar region was enriched in HDO by a factor of seven relative to Earth’s ocean water, implying that water in Mars’s permanent ice caps is enriched eight-fold. Mars must have lost a volume of water 6.5 times larger than the present polar caps to provide such a high level of enrichment. The volume of Mars’s early ocean must have been at least 20 million cubic kilometres.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Based on the surface of Mars today, a likely location for this water would be the Northern Plains, which have long been considered a good candidate because of their low-lying ground. An ancient ocean there would have covered 19% of the planet’s surface — by comparison, the Atlantic Ocean occupies 17% of the Earth’s surface.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><i>“With Mars losing that much water, the planet was very likely wet for a longer period of time than previously thought, suggesting the planet might have been habitable for longer,”</i> said Michael Mumma, a senior scientist at Goddard and the second author on the paper.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">It is possible that Mars once had even more water, some of which may have been deposited below the surface. Because the new maps reveal microclimates and changes in the atmospheric water content over time, they may also prove to be useful in the continuing search for underground water.</div><br />Video Credit: ESO/M. Kornmesser<br />Explanation from: https://www.eso.org/public/videos/eso1509a/ and https://www.eso.org/public/news/eso1509/

The Planet full of Water: Mars 4 billion years ago

This artist’s impression shows how Mars may have looked about four billion years ago. The young planet Mars would have had enough water to c...

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Saturn's moon Titan

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNi5Z1rvcxv-B2IihNDpgNox_VleQvryAYBhM8E8FGr84ncRDwCu2joIKF1tmiu52nUVxL3lWhV7hzLM1_uxja8mTkY1IqLFXiCzPbHhQB0S45mdb05UPeEfyY7ueqowVPDX7sfrlgG9N1/s1600/titan.jpg" imageanchor="1"><img alt="titan" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNi5Z1rvcxv-B2IihNDpgNox_VleQvryAYBhM8E8FGr84ncRDwCu2joIKF1tmiu52nUVxL3lWhV7hzLM1_uxja8mTkY1IqLFXiCzPbHhQB0S45mdb05UPeEfyY7ueqowVPDX7sfrlgG9N1/s640/titan.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">This composite image shows an infrared view of Saturn's moon Titan from NASA's Cassini spacecraft, acquired during the mission's "T-114" flyby on November 13, 2015. The spacecraft's visual and infrared mapping spectrometer (VIMS) instrument made these observations, in which blue represents wavelengths centered at 1.3 microns, green represents 2.0 microns, and red represents 5.0 microns. A view at visible wavelengths (centered around 0.5 microns) would show only Titan's hazy atmosphere. The near-infrared wavelengths in this image allow Cassini's vision to penetrate the haze and reveal the moon's surface.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">During this Titan flyby, the spacecraft's closest-approach altitude was 6,200 miles (10,000 kilometers), which is considerably higher than those of typical flybys, which are around 750 miles (1,200 kilometers). The high flyby allowed VIMS to gather moderate-resolution views over wide areas (typically at a few kilometers per pixel).</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The view looks toward terrain that is mostly on the Saturn-facing hemisphere of Titan. The scene features the parallel, dark, dune-filled regions named Fensal (to the north) and Aztlan (to the south), which form the shape of a sideways letter "H."</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Several places on the image show the surface at higher resolution than elsewhere. These areas, called subframes, show more detail because they were acquired near closest approach. They have finer resolution, but cover smaller areas than data obtained when Cassini was farther away from Titan.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Near the limb at left, above center, is the best VIMS view so far of Titan's largest confirmed impact crater, Menrva. Similarly detailed subframes show eastern Xanadu, the basin Hotei Regio, and channels within bright terrains east of Xanadu..</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Due to the changing Saturnian seasons, in this late northern spring view, the illumination is significantly changed from that seen by VIMS during the "T-9" flyby on December 26, 2005. The sun has moved higher in the sky in Titan's northern hemisphere, and lower in the sky in the south, as northern summer approaches. This change in the sun's angle with respect to Titan's surface has made high southern latitudes appear darker, while northern latitudes appear brighter.</div><br />Image Credit: NASA/JPL/University of Arizona/University of Idaho<br />Explanation from: http://photojournal.jpl.nasa.gov/catalog/PIA20016

Saturn's moon Titan

This composite image shows an infrared view of Saturn's moon Titan from NASA's Cassini spacecraft, acquired during the mission's...

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Messier 78: a reflection nebula in Orion

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuYUJkz46q5E6AzbqOKK91G63cYLoGZDlBoUL-hxfr_QQJj8V2j0xsAt7pJ5VPk71XOv9epQ_jURDhqIAYT7VohJYO9rLpPc8qgBtbaWpA2Ay1fBPGG6zcSLg6rK7Pk5abkYuL0PfzZjPf/s1600/Messier-78-orion.jpg" imageanchor="1"><img alt="Messier 78: a reflection nebula in Orion" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuYUJkz46q5E6AzbqOKK91G63cYLoGZDlBoUL-hxfr_QQJj8V2j0xsAt7pJ5VPk71XOv9epQ_jURDhqIAYT7VohJYO9rLpPc8qgBtbaWpA2Ay1fBPGG6zcSLg6rK7Pk5abkYuL0PfzZjPf/s640/Messier-78-orion.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">This image of the reflection nebula Messier 78 was captured using the Wide Field Imager camera on the MPG/ESO 2.2-metre telescope at the La Silla Observatory, Chile. This colour picture was created from many monochrome exposures taken through blue, yellow/green and red filters, supplemented by exposures through a filter that isolates light from glowing hydrogen gas. The total exposure times were 9, 9, 17.5 and 15.5 minutes per filter, respectively.</div><br />Image Credit: ESO/Igor Chekalin<br />Explanation from: http://www.eso.org/public/images/eso1105a/

Messier 78: a reflection nebula in Orion

This image of the reflection nebula Messier 78 was captured using the Wide Field Imager camera on the MPG/ESO 2.2-metre telescope at the La ...

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Lightning over Grand Canyon National Park

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgAQwoicKYKGbjtVDbBBzLHkcKKrppbOR3zIdn2Not9Kn1gSPQEgCjodUjVe8ShD9lpc7wuQhhZWRgEsPItFth-tAcqQ2r4di7HvQx-NbqS23g6v15o9kUK4H4zo5Lfz6afD5Qtuq-sTP_8/s1600/Lightning-over-Grand-Canyon-National-Park.jpg" imageanchor="1"><img alt="Lightning over Grand Canyon National Park" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgAQwoicKYKGbjtVDbBBzLHkcKKrppbOR3zIdn2Not9Kn1gSPQEgCjodUjVe8ShD9lpc7wuQhhZWRgEsPItFth-tAcqQ2r4di7HvQx-NbqS23g6v15o9kUK4H4zo5Lfz6afD5Qtuq-sTP_8/s640/Lightning-over-Grand-Canyon-National-Park.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Grand Canyon, Arizona, USA</div><div style="text-align: center;">August 30, 2013</div><br />Image Credit & Copyright: Rex Features and Rolf Maeder

Lightning over Grand Canyon National Park

Grand Canyon, Arizona, USA August 30, 2013 Image Credit & Copyright: Rex Features and Rolf Maeder

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Solar Eruption

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3pBRwfXYiv1tTWJajpm-PjhkblOf3INtO-LLOTu2dkBoNZIdSt-1ygBv9OEbaf6pkpeeq7LgCx-eHIWwRT1hDtu8bt5ZCPodX6e2WmvVOpbHyRsIst-fcdjiZIUHZPWig_RFJ3y6WpIm1/s1600/solar-eruption.gif" imageanchor="1"><img alt="Solar Eruption" border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3pBRwfXYiv1tTWJajpm-PjhkblOf3INtO-LLOTu2dkBoNZIdSt-1ygBv9OEbaf6pkpeeq7LgCx-eHIWwRT1hDtu8bt5ZCPodX6e2WmvVOpbHyRsIst-fcdjiZIUHZPWig_RFJ3y6WpIm1/s640/solar-eruption.gif" title="" width="640" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">A solar eruption gracefully rose up from the Sun on December 31, 2012, twisting and turning. Magnetic forces drove the flow of plasma, but without sufficient force to overcome the Sun’s gravity much of the plasma fell back into the Sun.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">This four–hour event occurred from 10:20 am to 2:20 pm EST and was captured by NASA’s Solar Dynamics Observatory in extreme ultraviolet light shown here at a high cadence of an image every 36 seconds.</div><br />Video Credit: NASA/SDO

Solar Eruption

A solar eruption gracefully rose up from the Sun on December 31, 2012, twisting and turning. Magnetic forces drove the flow of plasma, but w...

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Colliding galaxies: NGC 6240

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNpxLX47fETcMt2Zl6SQ9w8-OOJG2Mvd1l5fNCsV4ruJjN8HaHFlnZfOsZME0kkg8Xe9smDbc4vBg44jlXiFmq6Y7wxMjtwtSEhhYYLE42mHFFVH6jB-hzGfsKKOpASHSrP1PLp_Q5s3w7/s1600/NGC-6240.jpg" imageanchor="1"><img alt="NGC 6240" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNpxLX47fETcMt2Zl6SQ9w8-OOJG2Mvd1l5fNCsV4ruJjN8HaHFlnZfOsZME0kkg8Xe9smDbc4vBg44jlXiFmq6Y7wxMjtwtSEhhYYLE42mHFFVH6jB-hzGfsKKOpASHSrP1PLp_Q5s3w7/s640/NGC-6240.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">NGC 6240 is a peculiar, butterfly- or lobster-shaped galaxy consisting of two smaller merging galaxies. It lies in the constellation of Ophiuchus, the Serpent Holder, some 400 million light-years away. Observations with NASA's Chandra X-ray Observatory have disclosed two giant black holes, about 3,000 light-years apart, which will drift toward one another and eventually merge together into a larger black hole. The merging process triggered dramatic star formation and sparked numerous supernova explosions. The merger will be complete in some tens to hundreds of millions of years.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">This image is part of a large collection of 59 images of merging galaxies taken by the Hubble Space Telescope and released on the occasion of its 18th anniversary on 24th April 2008.</div><br />Image Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)<br />Explanation from: https://www.spacetelescope.org/images/heic0810ai/

Colliding galaxies: NGC 6240

NGC 6240 is a peculiar, butterfly- or lobster-shaped galaxy consisting of two smaller merging galaxies. It lies in the constellation of Ophi...

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Comparison of the Earth to the Great Red Spot of Jupiter

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAX17qLOtb959x7R_Ynm4FMp4U-MiVxk-fdqMMq4GvX6jto3h7lLQiohyphenhypheniSl0QR8CnBqnJM10C82Xrr41R1CWn0CTf3LB6DDXXXlI4trerrB7nJ52wkUVjBmCfc6z4i8hh7zETsQ4Vhriv/s1600/Comparison-of-the-Earth-to-Great-Red-Spot.jpg" imageanchor="1"><img alt="Comparison of the Earth to the Great Red Spot of Jupiter" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAX17qLOtb959x7R_Ynm4FMp4U-MiVxk-fdqMMq4GvX6jto3h7lLQiohyphenhypheniSl0QR8CnBqnJM10C82Xrr41R1CWn0CTf3LB6DDXXXlI4trerrB7nJ52wkUVjBmCfc6z4i8hh7zETsQ4Vhriv/s640/Comparison-of-the-Earth-to-Great-Red-Spot.jpg" title="" /></a></div><br /><div style="text-align: center;"><span style="font-family: "georgia" , "times new roman" , serif; font-size: x-large;">The Earth</span></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to harbor life.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">According to evidence from radiometric dating and other sources, Earth was formed about 4.54 billion years ago. Earth gravitationally interacts with other objects in space, especially the Sun and the Moon. During one orbit around the Sun, Earth rotates about its own axis 366.26 times, creating 365.26 solar days or one sidereal year. Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). The Moon is Earth's only permanent natural satellite. Its gravitational interaction with Earth causes ocean tides, stabilizes the orientation of Earth's rotational axis, and gradually slows Earth's rotational rate.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. 71% of Earth's surface is covered with water, with the remainder consisting of continents and islands that together have many lakes and other sources of water that contribute to the hydrosphere. Earth's polar regions are mostly covered with ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the magnetic field, and a convecting mantle that drives plate tectonics.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Within its first billion years, life appeared in Earth's oceans and began to affect its atmosphere and surface, promoting the proliferation of aerobic as well as anaerobic organisms. Since then, the combination of Earth's distance from the Sun, its physical properties and its geological history have allowed life to thrive and evolve. The earliest undisputed life on Earth arose at least 3.5 billion years ago. Earlier physical evidence of life includes biogenic graphite in 3.7 billion-year-old metasedimentary rocks discovered in southwestern Greenland, as well as "remains of biotic life" found in 4.1 billion-year-old rocks in Western Australia. Earth's biodiversity has expanded continually except when interrupted by mass extinctions. Although scholars estimate that over 99% of all species of life (over five billion) that ever lived on Earth are extinct, there are still an estimated 10–14 million extant species, of which about 1.2 million have been documented and over 86% have not yet been described. Over 7.3 billion humans live on Earth and depend on its biosphere and minerals for their survival. Earth's human population is divided among about two hundred sovereign states which interact through diplomacy, conflict, travel, trade and communication media.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><br /></div><div style="text-align: center;"><span style="font-family: "georgia" , "times new roman" , serif; font-size: x-large;">Great Red Spot</span></div><div style="text-align: center;"><br /></div><div style="text-align: center;">The Great Red Spot is a persistent anticyclonic storm on the planet Jupiter, 22° south of the equator, which has lasted for at least 186 years and possibly as long as 351 years or more. The storm is large enough to be visible through Earth-based telescopes. It was probably first observed by Giovanni Domenico Cassini, who described it around 1665. The spot has been noticeably red at times throughout its observed history, yet has not been appreciably red in the visible spectrum since a rather brief period in the mid 1970s.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Storms such as this are not uncommon within the turbulent atmospheres of gas giants. Jupiter also has white ovals and brown ovals, which are lesser unnamed storms. White ovals tend to consist of relatively cool clouds within the upper atmosphere. Brown ovals are warmer and located within the "normal cloud layer". Such storms can last hours or centuries.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Before the Voyager missions, astronomers were highly uncertain of the Red Spot's nature. Many believed it to be a solid or liquid feature on Jupiter's surface.</div><br />Explanation from: https://en.wikipedia.org/wiki/Earth and https://en.wikipedia.org/wiki/Great_Red_Spot

Comparison of the Earth to the Great Red Spot of Jupiter

The Earth Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrest...

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