Mysterious dark energy helps universe expand
Published 19 December, 2008, 05:51
The latest scientific research has shown that so-called ‘dark energy’ is responsible for preventing galaxy clusters from getting too big. It may also be responsible for the expansion of the universe.
Scientist Alexey Vikhlinin used NASA's Earth-orbiting Chandra X-ray Observatory to study the formation of galactic clusters to discover that dark energy acts as a counter-force to gravity, keeping clusters of galaxies from overgrowing and the universe from contracting.
The scientists used the Chandra telescope to observe 86 galaxy clusters, around half of which were about 5.5 billion light-years away. Enormous halos of hot gas surrounding the clusters generate x-ray radiation. They represent the bulk of the cluster's matter. It helps astronomers to detect and study galaxy clusters even at great distances.
Observing how the clusters formed, Alexey Vikhlinin came to the conclusion that there was a slowdown in their growth about 5.5 billion years ago. He suggested that dark energy could be the cause of it.
“They're put on a diet, a permanent diet,” he said.
Dark energy is still a relatively new concept which appeared a decade ago when research showed that the universe, rather than shrinking as they had once thought, was expanding at an accelerating rate. The findings proved that there has to be a force at work that acts as a counterbalance to gravity – that being dark energy.
“It's much more important and abundant in the evolution of the universe than the atoms that make us up,” said Princeton theoretical astrophysicist David Spergal.
Some scientists connect dark energy to an ultra light subatomic particle, dubbed ‘quintessence’, that is associated with the kind of counter-gravitational force.
They suggest that this energy was responsible for the rapid expansion of the universe during the first trillionth of a second after the big bang.
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