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Globular Cluster Messier 68

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEGJ8zoiU_qDa5HcpglnNpH4ksIQAN-2lP59F6z175qN62JUAVtik-qqVnPaGChfRH14TzrgLfl1Oi7eI6S61fY1SKstK_IlyPjM48lfuZpp7AW-dWMUNWMsXaZeU4d6D0fHmWxGn01AM0/s1600/Globular-Cluster-Messier-68.jpg" imageanchor="1"><img alt="Globular Cluster Messier 68" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEGJ8zoiU_qDa5HcpglnNpH4ksIQAN-2lP59F6z175qN62JUAVtik-qqVnPaGChfRH14TzrgLfl1Oi7eI6S61fY1SKstK_IlyPjM48lfuZpp7AW-dWMUNWMsXaZeU4d6D0fHmWxGn01AM0/s640/Globular-Cluster-Messier-68.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">The NASA/ESA Hubble Space Telescope offers this delightful view of the crowded stellar encampment called Messier 68, a spherical, star-filled region of space known as a globular cluster. Mutual gravitational attraction amongst a cluster’s hundreds of thousands or even millions of stars keeps stellar members in check, allowing globular clusters to hang together for many billions of years.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Astronomers can measure the ages of globular clusters by looking at the light of their constituent stars. The chemical elements leave signatures in this light, and the starlight reveals that globular clusters' stars typically contain fewer heavy elements, such as carbon, oxygen and iron, than stars like the Sun. Since successive generations of stars gradually create these elements through nuclear fusion, stars having fewer of them are relics of earlier epochs in the Universe. Indeed, the stars in globular clusters rank among the oldest on record, dating back more than 10 billion years.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">More than 150 of these objects surround our Milky Way galaxy. On a galactic scale, globular clusters are indeed not all that big. In Messier 68's case, its constituent stars span a volume of space with a diameter of little more than a hundred light-years. The disc of the Milky Way, on the other hand, extends over some 100 000 light-years or more.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Messier 68 is located about 33 000 light-years from Earth in the constellation Hydra (The Female Water Snake). French astronomer Charles Messier notched the object as the sixty-eighth entry in his famous catalogue in 1780.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Hubble added Messier 68 to its own impressive list of cosmic targets in this image using the Wide Field Camera of Hubble’s Advanced Camera for Surveys. The image, which combines visible and infrared light, has a field of view of approximately 3.4 by 3.4 arcminutes.</div><br />Image Credit: ESA/Hubble & NASA<br />Explanation from: https://www.spacetelescope.org/images/potw1231a/

Globular Cluster Messier 68

The NASA/ESA Hubble Space Telescope offers this delightful view of the crowded stellar encampment called Messier 68, a spherical, star-fille...

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Maret 16, 2016

Moon's shadow on Indian Ocean seen from Space by DSCOVR Observatory

Moon's shadow on Indian Ocean seen from Space by DSCOVR Observatory

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

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Maret 16, 2016

Solar Prominence Eruption

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibEew-MGXmsn8nOwq5SSpi9jcUzWEmMpEe0iYwFmoZxMEted3Dfmy67PyaL-EIpVGNFJx6wLrLIJuZhdmGjsyEntRlrOpTxCkvzM1gU_lW9N0ZaGK2PiTByCymuxjtHwrmJGK-Ejl2gXrD/s1600/Solar-Prominence-Eruption.gif" imageanchor="1"><img alt="Solar Prominence Eruption" border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibEew-MGXmsn8nOwq5SSpi9jcUzWEmMpEe0iYwFmoZxMEted3Dfmy67PyaL-EIpVGNFJx6wLrLIJuZhdmGjsyEntRlrOpTxCkvzM1gU_lW9N0ZaGK2PiTByCymuxjtHwrmJGK-Ejl2gXrD/s640/Solar-Prominence-Eruption.gif" title="" width="440" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">When a rather large M 3.6 class flare occurred near the edge of the Sun on February 24, 2011, it blew out a gorgeous, waving mass of erupting plasma that swirled and twisted for 90 minutes. NASA’s Solar Dynamics Observatory captured the event in extreme ultraviolet light. Because SDO images are high definition, the team was able to zoom in on the flare and still see exquisite details. And using a cadence of a frame taken every 24 seconds, the sense of motion is, by all appearances, seamless.</div><br />Video Credit: NASA/SDO<br />Explanation from: http://www.nasa.gov/mission_pages/sunearth/news/News022411-monsterprom.html<br /><div style="-webkit-text-stroke-width: 0px; background-color: white; border: 0px; color: black; font-family: Arial, Helvetica, sans-serif; font-size: 12px; font-stretch: inherit; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 22.4px; margin: 1em 0px 0px; orphans: auto; outline: 0px; padding: 0px; text-align: start; text-indent: 0px; text-transform: none; vertical-align: baseline; white-space: normal; widows: 1; word-spacing: 0px;"></div>

Solar Prominence Eruption

When a rather large M 3.6 class flare occurred near the edge of the Sun on February 24, 2011, it blew out a gorgeous, waving mass of eruptin...

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Maret 16, 2016

Searching for the Origins of the Dinosaur-Killing Asteroid

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7Q50ZdCoNBQX9lRHQHD7T4Iv_lEmRV93FSbKO4H3PdWt8SPNASDp56a3zdpGqHkoQvDS-h6ID8W1qlqVcCalIQg3kz7Oy0lg_nb9_BBKILnCntHTqM4_C9cQOa_NDdVBPaU8XHnlFZUPE/s1600/Dinosaur-Killing-Asteroid.jpg" imageanchor="1"><img alt="Dinosaur-Killing Asteroid" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7Q50ZdCoNBQX9lRHQHD7T4Iv_lEmRV93FSbKO4H3PdWt8SPNASDp56a3zdpGqHkoQvDS-h6ID8W1qlqVcCalIQg3kz7Oy0lg_nb9_BBKILnCntHTqM4_C9cQOa_NDdVBPaU8XHnlFZUPE/s640/Dinosaur-Killing-Asteroid.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">This artist's concept shows a broken-up asteroid. Scientists think that a giant asteroid, which broke up long ago in the main asteroid belt between Mars and Jupiter, eventually made its way to Earth and led to the extinction of the dinosaurs. Data from NASA's WISE mission likely rules out the leading suspect, a member of a family of asteroids called Baptistina, so the search for the origins of the dinosaur-killing asteroid goes on.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Observations from NASA's Wide-field Infrared Survey Explorer (WISE) mission indicate the family of asteroids some believed was responsible for the demise of the dinosaurs is not likely the culprit, keeping open the case on one of Earth's greatest mysteries.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">While scientists are confident a large asteroid crashed into Earth approximately 65 million years ago, leading to the extinction of dinosaurs and some other life forms on our planet, they do not know exactly where the asteroid came from or how it made its way to Earth. A 2007 study using visible-light data from ground-based telescopes first suggested the remnant of a huge asteroid, known as Baptistina, as a possible suspect.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">According to that theory, Baptistina crashed into another asteroid in the main belt between Mars and Jupiter about 160 million years ago. The collision sent shattered pieces as big as mountains flying. One of those pieces was believed to have impacted Earth, causing the dinosaurs' extinction.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Since this scenario was first proposed, evidence developed that the so-called Baptistina family of asteroids was not the responsible party. With the new infrared observations from WISE, astronomers say Baptistina may finally be ruled out.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><i>"As a result of the WISE science team's investigation, the demise of the dinosaurs remains in the cold case files,"</i> said Lindley Johnson, program executive for the Near Earth Object (NEO) Observation Program at NASA Headquarters in Washington. <i>"The original calculations with visible light estimated the size and reflectivity of the Baptistina family members, leading to estimates of their age, but we now know those estimates were off. With infrared light, WISE was able to get a more accurate estimate, which throws the timing of the Baptistina theory into question."</i></div><div style="text-align: center;"><br /></div><div style="text-align: center;">WISE surveyed the entire celestial sky twice in infrared light from January 2010 to February 2011. The asteroid-hunting portion of the mission, called NEOWISE, used the data to catalogue more than 157,000 asteroids in the main belt and discovered more than 33,000 new ones.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Visible light reflects off an asteroid. Without knowing how reflective the surface of the asteroid is, it's hard to accurately establish size. Infrared observations allow a more accurate size estimate. They detect infrared light coming from the asteroid itself, which is related to the body's temperature and size. Once the size is known, the object's reflectivity can be re-calculated by combining infrared with visible-light data.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The NEOWISE team measured the reflectivity and the size of about 120,000 asteroids in the main belt, including 1,056 members of the Baptistina family. The scientists calculated the original parent Baptistina asteroid actually broke up closer to 80 million years ago, half as long as originally proposed.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">This calculation was possible because the size and reflectivity of the asteroid family members indicate how much time would have been required to reach their current locations -- larger asteroids would not disperse in their orbits as fast as smaller ones. The results revealed a chunk of the original Baptistina asteroid needed to hit Earth in less time than previously believed, in just about 15 million years, to cause the extinction of the dinosaurs.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><i>"This doesn't give the remnants from the collision very much time to move into a resonance spot, and get flung down to Earth 65 million years ago,"</i> said Amy Mainzer, a co-author of a new study appearing in the Astrophysical Journal and the principal investigator of NEOWISE at NASA's Jet Propulsion Laboratory (JPL) in Pasadena. Calif. <i>"This process is thought to normally take many tens of millions of years."</i> Resonances are areas in the main belt where gravity nudges from Jupiter and Saturn can act like a pinball machine to fling asteroids out of the main belt and into the region near Earth.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">The asteroid family that produced the dinosaur-killing asteroid remains at large. Evidence that a 10-kilometer (about 6.2-mile) asteroid impacted Earth 65 million years ago includes a huge, crater-shaped structure in the Gulf of Mexico and rare minerals in the fossil record, which are common in meteorites but seldom found in Earth's crust. In addition to the Baptistina results, the NEOWISE study shows various main belt asteroid families have similar reflective properties. The team hopes to use NEOWISE data to disentangle families that overlap and trace their histories.</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><i>"We are working on creating an asteroid family tree of sorts,"</i> said Joseph Masiero, the lead author of the study. <i>"We are starting to refine our picture of how the asteroids in the main belt smashed together and mixed up."</i></div><br />Image Credit: NASA/JPL-Caltech<br />Explanation from: http://www.nasa.gov/mission_pages/WISE/multimedia/gallery/pia14729.html and http://www.nasa.gov/mission_pages/WISE/news/wise20110919.html

Searching for the Origins of the Dinosaur-Killing Asteroid

This artist's concept shows a broken-up asteroid. Scientists think that a giant asteroid, which broke up long ago in the main asteroid b...

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Maret 15, 2016

Aurora over Indian Ocean seen from the International Space Station

Aurora over Indian Ocean seen from the International Space Station

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

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Maret 15, 2016

2016 Total Solar Eclipse

2016 Total Solar Eclipse

Ternate, Maluku Islands, Indonesia March 9, 2016 Image Credit & Copyright: Babak Tafreshi

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Maret 15, 2016

Hubble image of our closest stellar neighbour: Proxima Centauri

<div style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoVQiMM7tdRCKs_UnnARK74rdPpVWJQRqK2x1l50wnUApPyRGTLc5psYVyKYHCo5TNSxzTQqA415Nc3bdhInEm2O4Z7Zu6jnNdpgPoQO9pYDzTu9s0qt39B88Q_oz38NbUQU2RFU5-VQ6Y/s1600/Proxima-Centauri.jpg" imageanchor="1"><img alt="Proxima Centauri" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoVQiMM7tdRCKs_UnnARK74rdPpVWJQRqK2x1l50wnUApPyRGTLc5psYVyKYHCo5TNSxzTQqA415Nc3bdhInEm2O4Z7Zu6jnNdpgPoQO9pYDzTu9s0qt39B88Q_oz38NbUQU2RFU5-VQ6Y/s640/Proxima-Centauri.jpg" title="" /></a></div><div style="text-align: center;"><br /></div><div style="text-align: center;">Shining brightly in this Hubble image is our closest stellar neighbour: Proxima Centauri.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Proxima Centauri lies in the constellation of Centaurus (The Centaur), just over four light-years from Earth. Although it looks bright through the eye of Hubble, as you might expect from the nearest star to the Solar System, Proxima Centauri is not visible to the naked eye. Its average luminosity is very low, and it is quite small compared to other stars, at only about an eighth of the mass of the Sun.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">However, on occasion, its brightness increases. Proxima is what is known as a “flare star”, meaning that convection processes within the star’s body make it prone to random and dramatic changes in brightness. The convection processes not only trigger brilliant bursts of starlight but, combined with other factors, mean that Proxima Centauri is in for a very long life. Astronomers predict that this star will remain middle-aged — or a “main sequence” star in astronomical terms — for another four trillion years, some 300 times the age of the current Universe.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">These observations were taken using Hubble’s Wide Field and Planetary Camera 2 (WFPC2). Proxima Centauri is actually part of a triple star system — its two companions, Alpha Centauri A and B, lie out of frame.</div><div style="text-align: center;"><br /></div><div style="text-align: center;">Although by cosmic standards it is a close neighbour, Proxima Centauri remains a point-like object even using Hubble’s eagle-eyed vision, hinting at the vast scale of the Universe around us.</div><br />Image Credit: ESA/Hubble & NASA<br />Explanation from: http://www.spacetelescope.org/images/potw1343a/

Hubble image of our closest stellar neighbour: Proxima Centauri

Shining brightly in this Hubble image is our closest stellar neighbour: Proxima Centauri. Proxima Centauri lies in the constellation of Cent...

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Maret 14, 2016