London, July 01: Intense heat from the first stars and black holes "killed" millions of would-be galaxies in the early universe, a new research has revealed.However, our Milky Way galaxy only survived as it was already immersed in a large clump of dark matter which trapped gases inside it, an international team, led by the University of Durham, has found in its research.
According to planetary scientists, the early Milky Way, which had begun forming stars, held on to the raw gaseous material from which further stars would be made. This material would otherwise have been evaporated by the high temperatures generated by "ignition" of the universe after the Big Bang.
Tiny galaxies inside small clumps of dark matter, were blasted away by heat which reached approximate temperatures of between 20,000 and 100,000 degrees centigrade, they said.
Dark matter is thought to make up 85 per cent of the Universe's mass and is believed to be one of the building blocks of galaxy formation.
Using computer simulations, the team examined why galaxies like the Milky Way have so few companion galaxies or satellites. The simulations revealed hundreds of thousands of small clumps of dark matter should be orbiting our galaxy.
The scientists said the heat from the early stars and black holes rendered this dark matter barren and unable to support the development of satellite star systems.
Joint lead investigator Professor Carlos Frenk said: "The validity of the standard model of our Universe hinges on finding a satisfactory explanation for why galaxies like the Milky Way have so few companions.
"The simulations show that hundreds of thousands of small dark matter clumps should be orbiting the Milky Way, but they didn't form galaxies. We can demonstrate that it was almost impossible for these potential galaxies to survive the extreme heat generated by the first stars and black holes.
"The heat evaporated gas from the small dark matter clumps, rendering them barren. Only a few dozen front-runners which had a head start on making stars before the Universe ignited managed to survive."
And, by providing a natural explanation for the origin of galaxies, the simulations support the view that cold dark matter is the best candidate for mysterious materials believed to make up the majority of our Universe, the scientists said.
The findings are to be presented at The Unity of the Universe conference in Portsmouth.
Bureau Report
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