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I'm at the Institute for Computational Cosmology
at Durham University,

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where they have simulated a universe.

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JAIME SALCIDO: One of the main projects in
the Institute for Computational Cosmology

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is to simulate how galaxies form and evolve.

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We do that from initial conditions after the
Big Bang,

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in cosmological terms,

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and we simulate expansion of the universe,

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the gravitational forces of matter,

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the dynamics of the cosmic gas,

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and the formation of stars and black holes.

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And the aim of the project is to understand
how galaxies form and evolve.

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DR MICHELLE FURLONG: The simulation is 300
million light years per side.

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So particles in the simulation are the size
of a million Suns.

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So that means a galaxy, say the size of our
own Milky Way galaxy,

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would be made up of around 10,000 particles.

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We ran on 4,096 cores. It took 43 days to
run.

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I think I worked it once, it'd take something
like 300 years to run

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if you were to run it - if you were to be
able to

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fit it on a single laptop and run it in that
time.

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JS: The oldest light of the universe, the
cosmic microwave background,

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has the imprint of the distribution of matter
in the universe

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when it was very young. So we use the observation
of this light

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to use as initial conditions in our simulations

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and we just let the gravity do the magic,

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and everything evolves stars and galaxies
as the ones we see in the universe.

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MF: The universe is made up of dark energy,
which is around 75%,

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and dark matter, which is a little over 20%,

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and baryons, ordinary matter, they only make
up around 4%.

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This is something that has been found observationally

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but has not yet been explained from a theoretical
point of view.

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But even though we don't actually know what
dark energy is

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we can simulate it and include it in the simulations

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because we understand its nature, to some
extent.

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JS: As theorists, one of the main aims is
to reproduce the observable universe.

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So one of the things really cool about the
simulation

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is that we can use it to predict some of the
things

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that can be observed with real telescopes.

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So we talk to astronomers that use the latest
telescopes

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so they can test out theories with real observations.

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TS: Thank you to everyone at the Institute
for Computational Cosmology at Durham University.

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If you want to know more about the EAGLE Project
and their simulations,

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links are on screen now.

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