So it was just another day in space for good old Spitzer, NASA's pride and joy of a space-scope. It's infra-red eyes were scanning a part of a distant galaxy called blah blah blah, (actually it's CL0958+4702) when something was spotted so incredible, though expected, still so amazing to finally see what previously we could only imagine with computer animation. About 5 billion light years away, it spotted an unusually large plume of light emerging from the "clash" of four blob-shaped galaxies. Three of these galaxies were the size of ours, the other almost 4 times as large.
Nothing astrophysicists hadn't known would happen, this merging of four distant galaxies. From previous posts you might recall that our own Milky Way is set to merge with our nearest galactic neighbor, Andromeda, in 5 billion years. Anyway, this four-part merger was the largest ever "seen" and we've been able to witness many. This one was beyond gigantic. Billions of elderly stars were ejected out during the clash, and about half will eventually fall back into whatever galaxy will remain. Imagine its size. It could be the largest galaxy the universe has ever known, once it finally forms itself into that body. Easily 10 times the size of our own Milky Way - and these were also elliptical galaxies that collided, or merged, not spiral.
This one is different because, unlike other known mergers, the galaxies involved in this quadruple collision have no gas, and that's the fuel source material that gives birth to stars. As a result, astronomers predict that relatively few new stars will be born in this new, ultra-immense new galaxy. Without stars, there's little chance of life emerging on any astral body orbiting one. Once again, it gives me that odd feeling about the incredible rarity of life, anywhere.
Basics courtesy of Sky & Telescope, R&L, Skywatcher, Spacecom.