The Universe in a Computer

As the universe stretches from a size smaller than an atom to thousands and then billions of miles across, these tears in its fabric are also stretched - think of the spray paint tearing ever wider on that balloon. After a few million years, the universe has become a dark, freezing place full of clouds of hydrogen and helium - plus a great deal of that mysterious dark matter. All this matter is spread across the universe in an uneven way by the primordial tears created by the Big Bang. It is at this moment that the dark matter really comes into its own. Its powerful gravitational pull starts sculpting the gas of ordinary atoms into what scientists call the cosmic web: it's this amazing process that is so beautifully shown by the Millennium Simulation. Inside the web, 'halos' of dark matter draw the gas into tighter and tighter clumps. The atoms of hydrogen, shoved together by the power of the dark matter, begin to heat - and eventually ignite as the first giant stars of the universe.

The final result is this: two galaxies. One is made by a computer. The other is 'real'. Can you tell them apart?

Frenk's conclusion is upbeat: "The galaxies generated in the simulation are almost indistinguishable from the real galaxies, and the similarity between the simulated and the real galaxy tells us that the assumptions that we have put into the simulation concerning how the Universe began, concerning the identity of the dark matter and concerning the laws of physics, that those assumptions provide a good description of what we see in nature. So the similarity between the virtual and the real galaxies are a nice confirmation of our cosmological model of the Universe."

For more information and to watch video of the simulation:

Video: Birth of the Universe [FirstScience presents]
We travel through space and time to reveal the amazing story of how the universe was born, how it created everything in our world, and eventually how it will die.

Millennium Simulation
http://www.mpa-garching.mpg.de/galform/press/

Millennium Simulation - The Largest Ever Model of the Universe
http://www.pparc.ac.uk/Nw/millennium_sim.asp