A new study performed with the help of the Chandra X-ray Observatory, focused on galaxy clusters, indicated that they are forming at a slower rate than they should be, which is considered a new piece of evidence in the complicated case of dark energy. These results, in tandem with those of previous extensive research, helped scientists get a better view on what dark energy may be and on what it does. One thought that derives from the new approach is that dark energy strikingly resembles Einstein's cosmological constant, which he added to his relativity theory.

Scientists are now pretty sure that dark matter behaves as a constrainer, while dark energy acts as a repeller, pushing matter apart and expanding the universe. The effect of the dark energy was inferred from the results of Chandra's mass and distance measurements of the 100 million degree hot gas in 86 galaxy clusters.

 

Based on these numbers, the leader of the study, Alexey Vikhlinin, from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, estimates that, without dark energy, gravity should have caused 50 times more galaxies to form within the last 5.5 billion years than there already were. Instead, the galaxy amount increased only by a factor of 10. "This is an unmistakable signature of dark energy," shared Vikhlinin, quoted by New Scientist.

 

It appears that dark energy is the thing that Einstein predicted in early 1900's, his cosmological constant that he believed to be wrong for a long time. He came up with this theory as a way of explaining why gravity doesn't cause the universe to collapse upon itself, but he ruled it out when he learned that the universe was actually expanding and not in a static balance, as he believed. The new research proves him right, though.

 

"Putting all of this data together gives us the strongest evidence yet that dark energy is the cosmological constant, or in other words, that 'nothing weighs something,'" stated Vikhlinin in a press release, as cited by Wired. "A lot more testing is needed, but so far Einstein's theory is looking as good as ever."