![]() ![]() This concept was revived with the discovery of the accelerating expansion of the Universe, with its main component being a kind of energy included in spacetime itself, called vacuum energy. This was linked to a concept Einstein had proposed but later discarded – a ‘cosmological constant’ that opposed gravity and kept the Universe from collapsing. To account for this, it was proposed that a ‘dark energy’ was responsible for pushing things apart more strongly than gravity. This is difficult to explain – the pull of gravity between all objects in the Universe should be slowing the expansion down. ![]() In the 1990s, it was discovered that the expansion of the Universe is accelerating – everything is moving away from everything else at a faster and faster rate. Study co-author Dr Chris Pearson, from STFC RAL Space, said: “If the theory holds, then this is going to revolutionise the whole of cosmology, because at last we've got a solution for the origin of dark energy that's been perplexing cosmologists and theoretical physicists for more than 20 years.” Gravity versus dark energy We started off looking at how black holes grow over time, and may have found the answer to one of the biggest problems in cosmology.” ![]() Study co-author Dr Dave Clements, from the Department of Physics at Imperial, said: “This is a really surprising result. The work is published in two papers in the journals The Astrophysical Journal and The Astrophysical Journal Letters. The conclusion was reached by a team of 17 researchers in nine countries, led by the University of Hawai’i and including Imperial College London and STFC RAL Space physicists. We started off looking at how black holes grow over time, and may have found the answer to one of the biggest problems in cosmology. The result potentially means nothing new has to be added to our picture of the Universe to account for dark energy: black holes combined with Einstein’s gravity are the source. The measurements from ancient and dormant galaxies show black holes growing more than expected, aligning with a phenomenon predicted in Einstein's theory of gravity. Observations of supermassive black holes at the centres of galaxies point to a likely source of dark energy – the ‘missing’ 70% of the Universe. ![]()
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