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Astronomers set a new galaxy distance record

5 May 2015 Astronomy Now

An international team of astronomers has pushed back the cosmic frontier of galaxy exploration to a time when the universe was only 5 percent of its present age with the discovery of an exceptionally luminous galaxy more than 13 billion light-years from Earth. The galaxy existed so long ago, it appears to be only 100 million years old.

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The dark matter conspiracy

3 May 2015 Astronomy Now

A new study finds that elliptical galaxies maintain a remarkably constant circular speed out to large distances from their centres, in the same way that spiral galaxies do. In these very different types of galaxies, stars and dark matter somehow conspire to redistribute themselves to produce this effect, or does modified Newtonian dynamics offer an explanation?

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Active asteroid spun so fast that it exploded

23 March 2015 Astronomy Now

Astronomers used the 10-metre Keck II telescope in Hawaii to examine a so-called active asteroid, P/2012 F5, that mimics a comet with a tail, but ejects dust like a shot without an obvious reason. The researchers found that it had a very fast spin rate and probably fragmented.

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Mars lost an ocean’s worth of water

6 March 2015 Astronomy Now

NASA scientists have determined that a primitive ocean occupying almost half of Mars’ northern hemisphere once held more water than Earth’s Arctic Ocean and that the Red Planet has lost 87% of that water to space.