We Finally Have Data on Which Nearby Stars Could Send Comets Crashing Into Earth


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According to ScienceAlert

 

By estimating the paths of several hundred thousand stars in the Milky Way galaxy, scientists have sketched out some back-of-the-envelope calculations on how likely it is that any could nudge a comet or two out of orbit and into our neighbourhood.

The bad news is there are around two dozen stars that could come close enough to stir up trouble. But don’t worry, we’re looking at a time scale of the next million years, so we can put comet strike down the bottom of the list of humanity’s biggest concerns.

Researchers from the Max Planck Institute for Astronomy used data from the Gaia Space Telescope to track the orbits of around 320,000 stars as they slowly made their way around the Milky Way galaxy, and then predict which ones would come within a galactic whisper of our own Solar System.

Right now our Sun’s closest stellar neighbour is Proxima Centauri, one of a trio of stars about 4.3 light years away.

That’s hardly an easy rocket jump away, but in galactic scales that’s still close enough for their gravity to gently pull on objects on the edge of our Solar System in a zone called the Oort cloud.

Not a lot of sunlight makes it out that far, so astronomers haven’t actually seen this celestial backwater. Instead they assume its presence, since every now and then a piece of it veers out of its massive orbit and tumbles towards the Sun, streaming dust and gas in a long, iconic tail.

Read more…

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This article and images were originally posted on [ScienceAlert] August 31, 2017 at 11:15PM

Credit to Author and ScienceAlert

 

 

 

 

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