Sun Is Moving Slower Than Thought
“Shocking” find may redraw picture of solar system’s cosmic shield.
The sun is moving through the Milky Way slower than previously thought, according to new data from a NASA spacecraft.
From its orbit around Earth, the Interstellar Boundary Explorer (IBEX) satellitemeasured the speeds of interstellar particles entering at the fringes of our solar system, 9 billion miles (14.5 billion kilometers) from the sun.
Plugging the new data into computer models, the IBEX team calculates that the sun is moving at about 52,000 miles (83,700 kilometers) an hour—about 7,000 miles (11,000 kilometers) slower than thought.
The discovery suggests that the protective boundary separating our solar system from the rest of the galaxy is missing a bow shock, a major structural component thought to control the influx of high-energy cosmic rays.
(via fyeahcarlsagan)
Source: National Geographic
Cosmic Avenger
Image courtesy SSRO/PROMPT/CTIO
Before he joins the Avengers, Thor may need to retrieve his helmet—which is floating in space 15,000 light-years away.
Also known as NGC 2359, Thor’s Helmet is a nebula found in the constellation Canis Major. As seen in this recently released picture from the Cerro Tololo Inter-American Observatory in Chile, the cosmic cloud of dust and gas is being shaped like a winged helm by outpourings of radiation from the massive stars inside.
Source: National Geographic
Two of a kind
Enigmatic Titan
Titan’s golden, smog-like atmosphere and complex layered hazes appear to Cassini as a luminous ring around the planet-sized moon. The world beneath that haze has become slightly less mysterious under the gaze of Cassini and its Huygens probe, but many new discoveries await.
Credit: NASA/JPL/Space Science Institute
Enceladus: A Tectonic Feast
The Cassini spacecraft has been studying Saturn and its moons since it entered orbit in 2004. This image, taken on Oct. 5, 2008, is a stunning mosaic of the geologically active Enceladus after a Cassini flyby.
Credit: NASA/JPL/Space Science Institute
Source: expose-the-light
How did the Equatorial Ridge on Saturn’s Moon Iapetus Form?
Saturn’s moon Iapetus is one of the most unusual moons in our solar system.
Perhaps the most bizarre feature of Iapetus is its equatorial ridge, a 20-km (12.4- mi) high, 200-km (124-mi) wide mountain range that runs exactly along the equator, circling more than 75 percent of the moon.
No other body in the solar system exhibits such a feature, and as Dombard et al. show, previous models have been unable to adequately explain how the ridge formed.
The authors now propose that the ridge formed from an ancient giant impact that produced a subsatellite around Iapetus.
Tidal interactions with Iapetus ultimately led to orbital decay, eventually bringing the subsatellite close enough that the same forces tore it apart, forming a debris ring around Iapetus.
Material from this debris ring then rained down on Iapetus, creating the mountain ring along the equator.
More information: Delayed formation of the equatorial ridge on Iapetus from a subsatellite created in a giant impact, Journal of Geophysical Research-Planets, doi:10.1029/2011JE004010 , 2012.
Source: physorg.com
![Preview of a Forthcoming Supernova
At the turn of the 19th century, the binary star system Eta Carinae was faint and undistinguished. In the first decades of the century, it became brighter and brighter, until, by April 1843, it was the second brightest star in the sky, outshone only by Sirius (which is almost a thousand times closer to Earth). In the years that followed, it gradually dimmed again and by the 20th century was totally invisible to the naked eye.
The star has continued to vary in brightness ever since, and while it is once again visible to the naked eye on a dark night, it has never again come close to its peak of 1843.
NASA’s Hubble Telescope captured an image of Eta Carinae. This image consists of ultraviolet and visible light images from the High Resolution Channel of Hubble’s Advanced Camera for Surveys. The field of view is approximately 30 arcseconds across.
The larger of the two stars in the Eta Carinae system is a huge and unstable star that is nearing the end of its life, and the event that the 19th century astronomers observed was a stellar near-death experience. Scientists call these outbursts supernova impostor events, because they appear similar to supernovae but stop just short of destroying their star.
Although 19th century astronomers did not have telescopes powerful enough to see the 1843 outburst in detail, its effects can be studied today. The huge clouds of matter thrown out a century and a half ago, known as the Homunculus Nebula, have been a regular target for Hubble since its launch in 1990. This image, taken with the Advanced Camera for Surveys High Resolution Channel, is the most detailed yet, and shows how the material from the star was not thrown out in a uniform manner, but forms a huge dumbbell shape.
Eta Carinae is not only interesting because of its past, but also because of its future. It is one of the closest stars to Earth that is likely to explode in a supernova in the relatively near future (though in astronomical timescales the “near future” could still be a million years away). When it does, expect an impressive view from Earth, far brighter still than its last outburst: SN 2006gy, the brightest supernova ever observed, came from a star of the same type, though from a galaxy over 200 million light-years away.
Credit: ESA/NASA [x]](http://24.media.tumblr.com/tumblr_lzzgi2KAJo1r0uejeo1_1280.jpg)
Preview of a Forthcoming Supernova
At the turn of the 19th century, the binary star system Eta Carinae was faint and undistinguished. In the first decades of the century, it became brighter and brighter, until, by April 1843, it was the second brightest star in the sky, outshone only by Sirius (which is almost a thousand times closer to Earth). In the years that followed, it gradually dimmed again and by the 20th century was totally invisible to the naked eye.
The star has continued to vary in brightness ever since, and while it is once again visible to the naked eye on a dark night, it has never again come close to its peak of 1843.
NASA’s Hubble Telescope captured an image of Eta Carinae. This image consists of ultraviolet and visible light images from the High Resolution Channel of Hubble’s Advanced Camera for Surveys. The field of view is approximately 30 arcseconds across.
The larger of the two stars in the Eta Carinae system is a huge and unstable star that is nearing the end of its life, and the event that the 19th century astronomers observed was a stellar near-death experience. Scientists call these outbursts supernova impostor events, because they appear similar to supernovae but stop just short of destroying their star.
Although 19th century astronomers did not have telescopes powerful enough to see the 1843 outburst in detail, its effects can be studied today. The huge clouds of matter thrown out a century and a half ago, known as the Homunculus Nebula, have been a regular target for Hubble since its launch in 1990. This image, taken with the Advanced Camera for Surveys High Resolution Channel, is the most detailed yet, and shows how the material from the star was not thrown out in a uniform manner, but forms a huge dumbbell shape.
Eta Carinae is not only interesting because of its past, but also because of its future. It is one of the closest stars to Earth that is likely to explode in a supernova in the relatively near future (though in astronomical timescales the “near future” could still be a million years away). When it does, expect an impressive view from Earth, far brighter still than its last outburst: SN 2006gy, the brightest supernova ever observed, came from a star of the same type, though from a galaxy over 200 million light-years away.
Credit: ESA/NASA [x]
![Enceladus Backlit by Saturn
This moon is shining by the light of its planet. Specifically, a large portion of Enceladus pictured above is illuminated primarily by sunlight first reflected from the planet Saturn. The result is that the normally snow-white moon appears in the gold color of Saturn’s cloud tops. As most of the illumination comes from the image left, a labyrinth of ridges throws notable shadows just to the right of the image center, while the kilometer-deep canyon Labtayt Sulci is visible just below. The bright thin crescent on the far right is the only part of Enceladus directly lit by the Sun. The above image was taken last year by the robotic Cassini spacecraft during a close pass by by the enigmatic moon. Inspection of the lower part of this digitally sharpened image reveals plumes of ice crystals thought to originate in a below-surface sea. [via]](http://25.media.tumblr.com/tumblr_lzkoraXbHs1r0uejeo1_1280.jpg)
Enceladus Backlit by Saturn
This moon is shining by the light of its planet. Specifically, a large portion of Enceladus pictured above is illuminated primarily by sunlight first reflected from the planet Saturn. The result is that the normally snow-white moon appears in the gold color of Saturn’s cloud tops. As most of the illumination comes from the image left, a labyrinth of ridges throws notable shadows just to the right of the image center, while the kilometer-deep canyon Labtayt Sulci is visible just below. The bright thin crescent on the far right is the only part of Enceladus directly lit by the Sun. The above image was taken last year by the robotic Cassini spacecraft during a close pass by by the enigmatic moon. Inspection of the lower part of this digitally sharpened image reveals plumes of ice crystals thought to originate in a below-surface sea. [via]
Merope Nebula
Black Eye Galaxy
NGC 2685
Bubble Nebula
