Dark energy, which continues to confound scientists, may actually be even more bizarre than previously imagined after a new study has now revealed that this strange force may actually change and grow stronger over time.
It was only fairly recently that scientists suggested the existence of dark energy as a way to make sense of the universe’s rapidly accelerating expansion. According to Live Science, at the present time, dark energy is considered to be a constant within the most popular astrophysical models of the universe, with some astronomers suggesting that it may even be a cosmological constant.
However, after scientists turned their attention to quasars, which are supermassive black holes, their research indicated that rather than being a constant, the mysterious force of dark energy may have actually changed and grown since the creation of the universe approximately 13.8 billion years ago.
Lead author Guido Risaliti, from the University of Florence in Italy, explained that after scientists studied quasars that could be dated back to just after the Big Bang, they discovered that dark energy appears to be growing even stronger with the passing of time.
“We observed quasars back to just a billion years after the Big Bang, and found that the universe’s expansion rate up to the present day was faster than we expected. This could mean dark is getting stronger as the cosmos grows older.”
In the new study on dark energy, scientists observed 1,600 quasars through the European Space Agency’s XMM-Newton spacecraft and NASA’s Chandra X-ray Observatory, so they could learn more about the X-ray light of these quasars, while the Sloan Digital Sky Survey was utilized to determine their UV output.
A great number of the quasars were found to be incredibly distant, and one, in particular, was found to have been emitting light since just 1.1 billion years after the Big Bang occurred.
It is important to note that many of the previous studies which were undertaken to explore the expansion rate of the universe and dark energy’s influence upon this were conducted by analyzing supernova explosions, which have been referred to as “standard candles.”
However, despite how incredibly powerful supernova explosions may be, they cannot be observed from nearly as far away as quasars, which means that by studying distant supermassive black holes, astronomers can take a much wider look at the universe’s expansion as stretched back even further in time.
However, in the new study, scientists did still observe supernovas, and Elisabetta Lusso of Durham University in England noted “[s]ince this is a new technique, we took extra steps to show that this method gives us reliable results. We showed that results from our technique match up with those from supernova measurements over the last 9 billion years, giving us confidence that our results are reliable at even earlier times.”
The new research on dark energy as it relates to quasars is strikingly similar to past observations of supernovas, which indicates that dark energy continues to grow faster as the universe expands.
“Some scientists suggested that new physics might be needed to explain this discrepancy, including the possibility that dark energy is growing in strength. Our new results agree with this suggestion,” as Risaliti explained.
The new study which has determined that dark energy changes and grows with time has been published in Nature Astronomy.