New study indicates that our universe is expanding much slower than earlier believedChris Middlebrooks (Author) Published Date : Apr 12, 2015 22:54 IST
A team of scientists led by Peter Milne of the University of Arizona has published a new study in the Astrophysical Journal indicating that following the Big Bang, our universe has not been expanding as fast enough as earlier thought.
Earlier studies proved that the expansion of the universe started after the Big Bang, but the new study seems to contradict this assertion. The team led by Milne found that type la supernovae largely differ from one another and never as similar as previously thought; the team also compared the differentiation to buying a random sample of 100-watt light bulbs, with most of them displaying varying levels of brightness.
We found that the differences are not random, but lead to separating Ia supernovae into two groups, where the group that is in the minority near us are in the majority at large distances and thus when the universe was younger, Milne observed. There are different populations out there, and they have not been recognized. The big assumption has been that as you go from near to far, type Ia supernovae are the same. That doesn t appear to be the case.
Using data from the Hubble telescope and the Swift satellite, Milne s team evaluated a considerable number of type la supernovae in ultraviolet and visible light, and found that supernovae are not too exact for determining the distance between stars, and may even be much closer than earlier believed.
The faraway supernovae should be like the ones nearby because they look like them, but because they re fainter than expected, it led people to conclude they re farther away than expected, and this in turn has led to the conclusion that the universe is expanding faster than it did in the past, Milne commented, suggesting that there may be less dark energy than what science textbooks suggest; dark energy is what scientists normally believe is the cause of accelerating expansion.
Until our paper, the two populations of supernovae were treated as the same population, he added. To get that final answer, you need to do all that work again, separately for the red and for the blue population.
New study indicates that our universe is expanding much slower than earlier believed