I love this stuff ...
Constructing Your Own Universe | Cosmic VarianceSo this is what Carlos was talking about. There are wonderful sets of simulations which he talked about, called the “Millennium Simulation” (ahem…remember an earlier post?). The bottom line is that these guys simply took really big computers and put in as much as we know about the basic equations of the universe, and then play with sprinkling in different amounts of cold dark matter and simulate the evolution of the universe tracking 10 billion individual particles in the simulation. They let the computers run until they get to the equivalent time of where we are now in the universe, and then then stop and look inside the computer. They take out the universe they’ve made and compare it to our universe. For that, you need to do an accurate survey of where all the stars and galaxies are in a large piece of the universe so that you can get good data on the distributions of the lumps, and other structures. The survey his team compared to was the “2DF” survey.
So what did they see? How well did their universes do? Well, in short, they look an awful lot like our universe when you have (the right amount of) cold dark matter sprinkled in. (”An awful lot” is not yet an established scientific term. Heck, it is not established English either. However, there are very specific tests (comparison of the power spectra of the size distributions of the structures) which work very well.)
This is great stuff, and confirms several other pieces of work by other teams. (See the references in their paper I’ll give the link to below.)
Here’s the really fun part you can do right from here. You can look at all the wonderful slides he showed by looking at the video of this talk when it comes up on the SUSY 2005 site, but even better you can download some of the high quality movies he showed right now! These are movies of flying around inside these newly created universes and seeing all of the wonderful organic-looking structures which form due to the clustering seeded by the CDM. You can see some of the hotspots that form at the intersections of some of these filamentary tendrils, which will be the birthplaces of stars. It is all rather beautiful.