Scientists have created an entire simulation of the universe in order to understand the formation of galaxies, stars and more.
The man-made cosmos is a computer simulation in which galaxies similar to those observed by astronomers grow and evolve.
Two of the world’s most powerful supercomputers – the ‘Cosmology Machine’ at the University of Durham and ‘Curie’ in Paris – were used to conduct the simulations, which took several months in total to run.
Previous attempts to model the formation of galaxies have met with little success, producing collections of stars that were often too massive, small, old or spherical.
Those produced in the Eagle (Evolution and Assembly of GaLaxies and their Environments) simulation are much more realistic.
One key to its success is the recreation of galactic winds – cosmic gas gales driven by stars, supernova explosions and supermassive black holes – which are stronger than those in earlier simulations, say the scientists.
Galactic winds affect the development of galaxies by blowing away the gas from which stars form.
The sizes and shapes of the thousands of galaxies produced in the Eagle simulation closely match their ‘real’ counterparts, and can be used to study the history of the universe almost as far back as the Big Bang 13.8 billion years ago.
Professor Richard Bower, from the University of Durham, said: ‘The universe generated by the computer is just like the real thing. There are galaxies everywhere, with all the shapes, sizes and colours I’ve seen with the world’s largest telescopes.
‘It is incredible. In the Eagle universe I can even press a button to make time run backwards.’
Results from the research will appear in the journal Monthly Notices of the Royal Astronomical Society tomorrow.
Co-author Dr Rob Crain, from Liverpool John Moores University, said: ‘This is the start of a new era for us. We can now manipulate the conditions of the universe and study the evolution of galaxies throughout the past 14 billion years.’
The Eagle simulation may also help in the hunt for one of the universe’s most elusive phenomena – dark matter.
Physicists say the simulations show that ‘halos’ of matter that formed as the universe developed could be evidence of the elusive substance.
Scientists believe that these clumps of dark matter, or halos, that emerged from the early universe trapped intergalactic gas and became the birthplaces of galaxies.
Cosmological theory predicts that our own cosmic neighbourhood should be teeming with millions of small halos containing galaxies, but only a few dozen such small galaxies have been observed around the Milky Way.
‘I’ve been losing sleep over this for the last 30 years,’ said Professor Carlos Frenk, Director of Durham University’s Institute for Computational Cosmology.
‘Dark matter is the key to everything we know about galaxies, but we still don’t know its exact nature.
‘Understanding how galaxies formed holds the key to the dark matter mystery.’
One of the biggest mysteries is why there isn’t a galaxy in every halo.
The researchers believe their simulations answer this question, showing explicitly how and why millions of halos around our galaxy and neighbouring Andromeda failed to produce galaxies and became barren.
They say the gas that would have made the galaxy was sterilised by the heat from the first stars that formed in the universe, and was prevented from cooling and turning into stars.
However, a few halos managed to bypass this cosmic furnace by growing early and fast enough to hold on to their gas and eventually form galaxies.
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