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| Image credit: Chandra |
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| Dark Matter Halo Puzzles Astronomers |
| Oct 26, 2004 - Astronomers using the Chandra X-Ray Observatory have discovered a huge halo of dark matter around an isolated elliptical galaxy; an object that shouldn't have such a halo, according to optical observations. The galaxy, NGC 4555, is unusual that it's a large elliptical galaxy which isn't part of a larger cluster of galaxies. It's surrounded by a cloud of gas, twice the size of the galaxy itself, that's been heated to 10-million-degrees Celsius. This gas could only get that hot if it was being constrained by a halo of dark matter ten times the mass of the stars in the galaxy. (Full Story) |
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| Image credit: NASA/JPL/SSI |
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| Cassini Closes in on Titan |
| Oct 26, 2004 - NASA's Cassini spacecraft will pass only 1,200 km (745 miles) above the surface of Titan today, delivering the most detailed pictures ever taken of the mysterious, methane covered moon. This image was taken on October 24, when the spacecraft was still more than 1.2 million km (745,000 miles) away, so the view is going to get much better. The photo was taken using a special filter that allows Cassini to mostly peer through the enshrouding methane atmosphere and see some of the moon's surface features, such as the bright, continent-sized Xanadu region. (Full Story) |
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