Tuesday, September 12, 2017

Korean astronomers saw a distant explosion 600 years ago — and we just found the stars that caused it

Korean astronomers saw a distant explosion 600 years ago — and we just found the stars that caused it:

In March of 1437, Korean astronomers in Seoul saw what they thought was a new, bright star appear in the night sky. Now, nearly 600 years later, astronomers have figured out what those stargazers actually saw: a thermonuclear explosion caused by the interaction of two distant stars. The new research pinpoints the location of those two stars in the sky, solving a mystery that’s plagued astronomers for decades and providing clues about what happens to pairs of stars centuries after they explode.

The event that the Korean astronomers saw lasted 14 days, leading modern astronomers to suspect it was something known as a classical nova. This is a type of explosion caused by an ordinary star similar to our Sun and a white dwarf — a small,...

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Jupiter's vividly glowing auroras have a mysterious power source

Jupiter's vividly glowing auroras have a mysterious power source:

For the first time ever, NASA’s Juno spacecraft has spotted electrons being fired down into Jupiter’s atmosphere at up to 400,000 volts. That’s an enormous amount of energy that gives rise to the planet’s glowing auroras. These incredibly high voltages, however, are only spotted occasionally — and that’s raising questions about what exactly is behind some of the planet’s most vivid glows at the poles.

The discovery, detailed in a study published today in Nature, was made possible by the instruments on board Juno, which has been orbiting Jupiter for a little over a year, passing by the poles closer than any other spacecraft has before. It confirms, in part, what astronomers expected, but it also shows that Jupiter’s auroras behave...

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