17th November 2008 by Giles Smith
From NASA Spitzer Project
NASA scientists have discovered that one of the closest solar systems to ours shows some very striking resemlblances to how are solar system looked when it was a lot younger.
The star at the center of the nearby system, called Epsilon Eridani, is a younger, slightly cooler and fainter version of the sun. Previously, astronomers had uncovered evidence for two possible planets in the system, and for a broad, outer ring of icy comets similar to our own Kuiper Belt.
The outer comet ring around Epsilon Eridani is denser than our comet ring, called the Kuiper belt, because the system is younger.
This new discovery should assist scientists and astronomers to model what our own solar system was like around the time life started taking hold on earth. Astronomers have discovered similar systems before but never one as close, only 10 light years away, to us.
“Because the system is so close to us, Spitzer can really pick out details in the dust, giving us a good look at the system’s architecture,”
said co-author Karl Stapelfeldt of NASA’s Jet Propulsion Laboratory, Pasadena, Calif.
Asteroid belts are often the left overs from planet formation. The formed planet will then shepherd the nearby belt keeping it in its disk like orbit around its star. An asteroid belt is much easier to detect than an individual planet, but its existence allows astronomers to deduce what the size and composition of nearby planets. Asteroid belts are detected by using infra-red telescopes which can pick out the small releases of heat given off when dust and particles in the belt collides.
Tags: asteroid, asteroid belt, earth, epsilon eridani, history, solar system
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22nd October 2008 by Giles Smith
Crater on North Polar Layered Deposits. Credit: NASA/JPL/University of Arizona
From the HiRISE Website
The north polar layered deposits, and the bright ice cap that covers them, are very young (by geologic standards) features. To try and figure out the age of an area, or how quickly it’s being resurfaced, planetary scientists count up the number of craters at different sizes. An older surface has more time to accumulate more craters whereas a younger surface, or one that has a lot of geologic activity that destroys craters, doesn’t have many impact craters.
These polar deposits have a very low crater count so it is possible that the ice cap (bright white in this image) might only by about 10,000 years old and the surface of the layered deposits (orange-brown in this image) may be only a few million years old. This sounds like a long time but is very short compared to other surfaces on Mars.
The ice has not melted because it is being sheltered from the sun by the high crater walls, keeping the contents of the crater well preserved.
So much for Mars being a dead planet, what with ice, avalanches, rain, moving sand dunes and weather systems, it seems quite alive!
Tags: crater, geologic, hirise, ice cap, mars, oyster
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14th October 2008 by Giles Smith
NASA Reconnaissance Orbiter
Quote from Universe Today
Reconnaissance Orbiter has been circling Mars for over two years now, and has provided unprecedented views of the Red Planet with its HiRISE Camera. But did you also know that MRO is a weather-monitoring satellite, too? The Mars Climate Sounder instrument is examining the Martian atmosphere and has issued its first Mars weather report. “It has taken 20 years and three missions but we finally have an instrument in orbit that gives us a detailed view of the entire atmosphere of Mars and it is already giving us fresh insights into the Martian climate,” said Professor Fred Taylor of Oxford University. Within a paper issued by the Mars ‘weather team’ comes surprising news: during the freezing Martian winter the atmosphere above the planet’s South Pole is considerably warmer than predicted.
I wonder if a Mars forecast will be just as reliable as the forecasts we get on Earth?
Tags: hirise, mars, nasa, reconnaissance orbiter, weather
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12th October 2008 by Giles Smith
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
MESSENGER is the first mission where a space craft has been sent to orbit Mercury, the closest planet to the sun. On October 6th 2008 at 04:40 the probe came within 200km of the toastie planet’s surface and took as many pictures as it could.
NASA is hoping that the probe will be in full orbit around the planet by 2011 and that MESSENGER will be Mercury’s first artificial satelite.
The very bright crater just south of the equator is Kuiper which was identified using photos from the 1970s. The area east of Kuiper has never been photographed, until MESSENGER.
Tags: mercury, messenger, nasa
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3rd October 2008 by Giles Smith
Illustration of the flare from magnetar Swift J195509+261406. A starquake is probably what triggered the object
Quote
Swift has made another unusual discovery. The orbiting satellite detected a very strange star that “twinkled” with gamma rays, X-rays, and light — and then vanished. Back in June the satellite detected a spike of gamma-rays that lasted less than five seconds. But this high-energy flash wasn’t a gamma-ray burst — the birth cry of a black hole far across the universe. It was something much closer to home. During the next three days, the object brightened and faded in visible light. It flashed over 40 times! Eleven days later, it flashed again, this time at infrared wavelengths. Then, it disappeared from view!
Tags: black hole, gamma ray, infrared, star, x-ray
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