It’s has been a while since the last “we’re all going to die” post, but this one is seriously cool. According to Nature, our galaxy is on a collision course with our nearest neighbor, Andromeda. Eventually the two galaxies will meet. Stars will smash into each other. The giant black holes at the center of each galaxy will duke it out for supremacy, one eventually eating the other. It will be awesome!
Um, except if you are caught in the middle of it. The astronomers who made this discovery have run simulations and they reckon that, as we are way out on the edge of our galaxy, we’ll probably be OK. They don’t say anything about the possibility of being bathed in vast fountains of gamma rays, though.
Still, the good news is that it won’t happen for 4 billion years. And long before that we may find that a trip to the nearest galaxy is no further than one to the other side of our own. How cool will that be?
Of course galaxies falling towards each other through gravitational attraction is not the norm for our universe. We know now that the universe is not only expanding, but that the rate of expansion is increasing. The latest Nobel Prize for physics was awarded to the guys whose observations proved that.
How that can be true, and what is means for cosmology, is explained in the following TED talk by Brian Greene. Along the way he gets into String Theory and explains how the ever-expanding universe might be proof that there are many others universes — not the classical multiverse produced by all probabilistic outcomes being true somewhere, but actual independent universes with their own separate big bangs.
The sad news is that we can’t see any of these other universes. Or at least, we won’t be able to unless our universe happens to accidentally collide with another one. Ooh, err…
I particularly am taken by his last point–that, in the far future, astronomers may conclude there is only one galaxy, one island of matter and nothing else, and it was always so…
Yeah, it’s a lovely idea. It’s also a long way in the future. The collision with Andromeda is 4 billion years off. A billion years or so later the sun is due to become a red giant. My guess is that the disappearance of the rest of the universe is billions of years away from that.
Two black holes enter; one leaves! The smackdown starts right now, er, right in 4 billion years. Get your tickets now, though!
I love these posts, and the separate multi-universe thing’s cool, too.