Most massive cosmic pileup ever seen

Blogs / Bad Astronomy



Hubble+Chandra+Keck image of MACSJ0717.5+3745, a collision of four galaxy clusters.
Credit: NASA, ESA, CXC, C. Ma, H. Ebeling, and E. Barrett (University of Hawaii/IfA), et al., and STScI.

That’s quite an image. It’s of an object 5.4 billion light years away called MACSJ0717.5+3745, which is really just a catalog number and a coordinate on the sky, so it’s not nearly as awesome sounding as what it is: a massive collision between four separate galaxy clusters!

Almost all galaxies reside in a group of some sort. The Milky Way is part of the local group, a few dozen galaxies, mostly dinky ones, of which we’re actually the largest. And our little enclave is in the suburbs of the Virgo cluster, a much larger aggregation of hundreds of galaxies. These clusters move around, and sometimes they collide (check out the Bullet Cluster, for example, for a fantastic example of this kind of collision, and how it gave us proof positive of the existence of dark matter).

But four clusters, colliding all at the same time? Wow!

more:

http://blogs.discovermagazine.com/badastronomy/2009/04/17/most-massive-cosmic-pileup-ever-seen/

Having 4 whole galaxy clusters coming together will not be a good day for anyone living within those clusters. They must be pissed! :smoke: