Turns out the fault actually does lie in the stars.

November 28, 2016 10:03 PM

We think of outer space as distant and unreachable, but in fact events out in the cosmos may have helped and hindered the evolution of life on Earth.
posted by smoke (3 comments total)

Thank you smoke, awesome stuff.
posted by valetta at 4:07 AM on November 29, 2016

It's the most complete list of cosmic dangers to life on Earth I have ever seen, and free of the scaremongering that often accompanies such pieces. Thank you!
posted by hat_eater at 6:18 AM on November 29, 2016

They're missing one big one, which is a bit surprising as they talk all around it with Nemesis and Planet X and their possible effect on the Oort Cloud.

Likelier than either of those options (I've not seen anyone take Nemesis seriously since the mid-1990s) is that a normal star can derange the Oort and cause a swarm of comets. People forget that stars move relative to the Sun as we all orbit around the galactic centre, and that sheer randomness will bring one fairly close every now and then.

For example, based on the best data from the ESA's Gaia satellite, the star Gliese 710 will be passing within 0.205 +/- 0.07 light years in about 1.3 million years. That's well within the Oort Cloud, and there's a small chance it might get close enough to impinge on the Kuiper Belt.

So it's not at all unreasonable to say that, on average every 100 million years or so (but randomly distributed), a mere garden-variety star sends a shower of comets our way. No mystery companions to the Sun or distant large planets necessary.
posted by Quindar Beep at 6:58 AM on November 29, 2016 [4 favorites]