Excerpt from space.com
Galaxies come in all different shapes and sizes, and a massive new simulation of the universe has captured that galactic variety with more accuracy than any simulation before it, according to a new study.
Using a simulation called EAGLE (Evolution and Assembly of GaLaxies and their Environments), researchers from multiple institutes in Europe have cooked up a dazzling simulation of the universe that contains tens of thousands of galaxies.
A sample of the new simulation can be seen in the video above. It shows the evolution of the universe in a region 25 megaparsecs cubed (about 81 million light years).
"This is really a staggering success, I think it's fair to say," Rob Crain from Liverpool John Moores University and a member of the group that built EAGLE, told Space.com. The researchers are part of a collaboration called the Virgo Consortium for Cosmological Supercomputer Simulations. "Go to our previous generation of simulations, and the galaxies all look like big spherical blobs. Now they form disks and bars and irregular galaxies and different types of ellipticals."
A computer simulation is like a recipe for the universe. Scientists have to start with a list of ingredients and instructions — which actually means a description of the physics that underlie the current universe. While many simulations can recreate the major cosmic ingredients (like stars and galaxies), the subtleties are harder to achieve (like the shape, mass and distribution of those stars and galaxies).
The bottom right corner of the screen shows the time after the Big Bang (denoted by "t"). In the early universe, matter is dispersed and hazy, but gradually coalesces into a sort of web, with long strands of material connecting nodes where galaxies are clustered. At 1:06, the simulation starts again from the beginning and shows the three major components of the model: dark matter (labeled as CDM), gas (the red globs are gas clouds where stars are often born), and stars. The full EAGLE simulation contains an area 100 megaparsecs cubed.
One goal of the EAGLE group was to produce a simulation large enough that it contained all types of galaxies seen in the universe. This allows the researchers to find out if the physics they programmed into EAGLE are accurate for all galaxies, and if they produce the correct number of galaxies in the universe.
Schaye said the picture of the universe created by the EAGLE simulation "is not perfect, but for astronomers the level of agreement is very impressive. It seems we have the main ingredients in place."