The ghostly remains of long ago black holes from another universe may lie in the depth of our own space-time continuum. That is the conclusion of a new study by a group of scientists with notes from Hawking employee Roger Penrose. The researchers examined the cosmic background radiation and identified places that could mark the graves of old black holes from a previous incarnation of the universe.
This research gathers various fascinating concepts in physics to speculate on conditions before and after a universe such as ours. Penrose and his colleagues call this conformal cyclic cosmology or CCC. The cycle can be driven by the way black holes grow and die in the universe.
The current leading theory says that our universe will continue to expand and cool until only black holes remain. According to Stephen Hawking's work decades ago, black holes are slowly losing energy by leaking photons and gravitons – we call this Hawking Radiation. So eventually even the black holes in a universe like ours will die.
That leaves only a soup of photons and gravitons, both of which have no mass and travel at the speed of light. That is why the theory of relativity dictates that these particles do not experience time or distance. A universe without time or distance is very similar to the compressed pre-universe before the big bang appears to be. So, maybe everything starts again, again and again.
The new study included scanning the cosmic microwave background (CMB) for signs of a previous universe, but there was a lot of interference from the Topical universe. Because the singularities of the pre-universe would have passed away for a long time, there is nothing more to discover. However, their impact on the universe through bleeding Hawking radiation for billions and billions of years should leave a mark.
Research co-author and mathematician Daniel An performed a statistical analysis on the CMB, which began with ignoring areas in the sky where starlight overwhelmed the CMB. He then marked areas with microwave frequencies in the expected range for a black hole grave monument. Finally, he compared the "best" agreements with artificially generated CMB data, which should have No black hole remnants. The comparison showed that the locations can indeed come from black holes in a previous universe.
The scientific community is far from convinced. A previous Penrose paper made a similar claim, but follow-up research pointed to various issues. It is now up to other researchers to assess the new evidence.
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