We’re doomed. According to a new model of how the Milky Way will interact with Andromeda, we may have as few as five billion years left.
The two biggest galaxies in the Local Group – of which ours is one – are on a collision course, and the first sideswipe starts in just two billion years. The sun won’t even have begun flickering. We may still be living here.
With a giant sucking sound (metaphorically speaking) Andromeda will start pulling spumes of gas out of our galaxy, moving on to whole star systems over the following hundred million years. The Milky Way will survive, after a fashion, and sweep out around Andromeda, but the respite will be brief. 1.4 billion years later the duo will dance again, and Andromeda’s bedraggled partner – us – then starts digesting. Five billion years from now, Andromeda and the Milky Way will merge, but it won’t be a merger of equals. Our sun may not even hold onto its planets; there’s a 3% chance the solar system will be torn apart, warm life-spawning Earth sent spinning into the darkness away from its still functional star.
When the mayhem settles down in seven billion years or so, the Earth – if it survives at all – will be a lump of rock much further from the galaxy’s happening downtown than it is today, inhabiting a cold belt of gas thousands of lightyears from the galactic centre. A distant bedroom ‘burb, instead of the funky Zone 2 it hangs in today.
It’s bad enough being destroyed in the cataclysm of two colliding galaxies, but to end up in the equivalent of Slough as a result? Pur-leez.
Five billion years. That’s all we’ve got.