Universe Has Lost Up To 5% Of Its Dark Matter Since Its Birth

Posted: Dec 29 2016, 1:02pm CST | by , in News | Latest Science News

 

Universe has Lost up to 5% of its Dark Matter Since its Birth
Credit: NASA/ESA
 

For the first time, Russian physicists have measured the loss of dark matter since the birth of the universe

Science says that most of the matter in the universe is dark. This dark matter is something they have yet to observe directly because it does not interact with regular matter in any way. Its presence is only felt through its gravitational effects.

Scientists also know that the proportion of dark matter has decreased since the birth of universe but they had never been able to measure the exact amount until now. Using data from observations of various cosmological effects, researchers estimate that universe has lost up to 5% of dark matter since the Big Bang some 13.7 billion years ago.

“The discrepancy between the cosmological parameters in the modern Universe and the Universe shortly after the Big Bang can be explained by the fact that the proportion of dark matter has decreased. We have now, for the first time, been able to calculate how much dark matter could have been lost and what the corresponding size of the unstable component would be.” Co-author Igor Tkachev, the Institute for Nuclear Research (INR) of the Russian Academy of Sciences said.

Dark matter was first theorized back in the 1930s when Swiss astronomer Fritz Zwicky observed weird movement of a cluster of galaxy, suggesting that it was under the effect of gravity from an unseen source. The source was undetectable expect for its gravitational effect. Thus, it was given the name dark matter. It was estimated that the dark matter accounts for 26.8% of total matter in the universe, 4.9% of ordinary matter while the rest is dark energy (68.3%). Dark matter is also held responsible for the expansion of universe. 

Despite all that, researchers still know very little about the nature of dark matter. When a team of Russian researchers studied observations from Planck telescope – which looks at fluctuations of cosmic microwave background or the “echo” of Big Bang – they noticed a problem there. Fluctuations showed huge difference in the cosmological parameters from the observable universe today compared with that seen in ancient universe. The findings suggest that the composition of earlier universe right after the Big Bang was considerably different from the modern one.

“This means that in today’s universe there is 5% less dark matter than in the recombination era,” said Tkachev. “We are not currently able to say how quickly this unstable part decayed; dark matter may still be disintegrating even now, although that would be a different and considerably more complex model.” 

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Hira Bashir covers daily affairs around the world.

 

 

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