What is dark matter? Elusive substance could be made of black holes from a different UNIVERSE, scientist claims
Dark matter could be even weirder than we thought, as a scientist claims the elusive substance could be made of black holes from a different universe.
Astronomers believe that dark matter makes up around 27 per cent of the universe's mass and holds galaxies together like gravitational glue.
Most scientists believe the strange material is made of an undiscovered particle that doesn't absorb or reflect normal light.
But a new theory suggests that dark matter might really be made of ancient black holes that existed before the Big Bang.
These 'relic' black holes from another universe are small, packed with mass, and would be totally invisible except for their gravitational tug.
According to Professor Enrique Gaztanaga, from the University of Portsmouth, this makes them the prime suspect in the search for dark matter.
The key to this bold suggestion is the suggestion that there was a universe before our current one, and the Big Bang was just the transition between the two.
Professor Gaztanaga says: 'The idea is that dark matter may not be a new particle, but instead a population of black holes formed in a previous collapsing phase and bounce of the Universe.'
The mysterious substance known as dark matter could really be made up of black holes from another universe, according to a scientist
According to the most common theory, the universe began as an infinitely dense point known as a 'singularity'.
This singularity then exploded out in a rapid phase of expansion known as inflation, the lingering energy from which we can still see as the Cosmic Microwave Background.
However, some scientists don't like the idea of a singularity because their infinitely dense interiors appear to break down the fundamental rules of physics as we know them.
To get around this issue, Professor Gaztanaga suggests we might live in a 'bouncing' universe.
According to this view, the universe collapsed in on itself at the end of its previous phase, falling inwards to an enormously, but not infinitely, dense point.
As the universe became more and more dense, it eventually hit a point where it 'bounced', rushing outwards in a period of inflation to form the universe we currently live in.
'The Big Bang corresponds to a bounce from a previous collapsing phase, rather than the absolute beginning of everything,' Professor Gaztanaga told the Daily Mail.
'So it is the start of the expansion we observe, but not necessarily the beginning of time itself.'
According to this theory, the Big Bang was not the start of the universe but simply a transition from a previous universe's collapse to our current one. Black holes from the earlier might have survived this transition and now make up dark matter
What makes this idea so important for dark matter is that Professor Gaztanaga says that black holes might have survived the collapse.
That means the black holes formed by the collapsing galaxies of the last universe could still be floating around our universe today.
Professor Gaztanaga says: 'These 'relic' black holes would survive into the expanding phase we observe today and behave exactly like dark matter: they interact gravitationally, but do not emit light.'
Although this sounds far–fetched, it actually helps avoid some thorny problems plaguing our current theory.
Scientists neither need to explain away the infinite density of the singularity nor add any mysterious extra particle to explain dark matter.
Likewise, the relic black hole theory could help explain some of the most puzzling discoveries made by the James Webb Space Telescope (JWST).
While peering back to capture some of the earliest light in the universe, the JWST found a group of very bright, red dots only a few hundred million years after the Big Bang.
Scientists think that these are rapidly growing black holes, potentially even ones that would become supermassive black holes in the hearts of galaxies.
The existence of these 'relic' black holes could explain the mysterious 'little red dot' black hole discovered by the James Webb Space Telescope, just a few hundred million years after the Big Bang
Our current understanding of the universe can't explain how they would have gotten so big, so fast.
But if relic black holes were already there at the very start of the universe, they would have had a massive head start that allowed them to grow much larger than expected.
Professor Gaztanaga admits there is still a lot of work to be done before his idea can be confirmed.
Scientists will need to test this theory against the data from the gravitational wave backgrounds and precise measurements of the Cosmic Microwave Background.
Professor Gaztanaga says: 'The key question is which idea matches observations — and that's something we can test.'
But if this theory could be proven, it would simultaneously solve two of the biggest puzzles facing scientists today.
Dark matter: The mysterious substance that makes up 27% of the universe that scientists cannot confirm
Dark matter is a hypothetical substance said to make up roughly 27 per cent of the universe.
The enigmatic material is invisible because it does not reflect light, and has never been directly observed by scientists.
Astronomers know it to be out there because of its gravitational effects on known matter.
The European Space Agency says: 'Shine a torch in a completely dark room, and you will see only what the torch illuminates.
Dark matter is a hypothetical substance said to make up roughly 27 per cent of the universe. It is thought to be the gravitational 'glue' that holds the galaxies together (artist's impression)
'That does not mean that the room around you does not exist.
'Similarly we know dark matter exists but have never observed it directly.'
The material is thought to be the gravitational 'glue' that holds the galaxies together.
Calculations show that many galaxies would be torn apart instead of rotating if they weren't held together by a large amount of dark matter.
Just five per cent the observable universe consists of known matter such as atoms and subatomic particles.
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