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The universe is decaying far more quickly than we previously thought, scientists have said.
But the end is still a long way off: 10^78, or a one with 78 zeroes, years away. Still, that is much longer than the previous estimate, which was 10^1100 years.
That is the time it will take for white dwarf stars to entirely decay. Those stars are the most long-lasting objects in the universe, and so should stay around for longest.
The new research is a follow-up to a 2023 paper that showed that not only black holes but also other objects could "evaporate" through a process similar to Hawking radiation. The new paper saw the researchers look to understand how long that process would take.
"The ultimate end of the universe comes much sooner than expected, but fortunately it still takes a very long time," said Heino Falcke, a black hole expert who was lead author on the new paper.
The findings build on Hawking radiation, which was first proposed by Stephen Hawking in 1975. He suggested that it was possible for black particles and radiation to escape from a black hole – at the edge, two particles would form, with one being sucked into the black hole and another escaping.
Eventually, through that process, the black hole very slowly decays, becoming instead particles and radiation.
The time that process takes for an object to evaporate depends how dense it is. Neutron stars and stellar black holes take 10^67 years, for instance.
The Moon and a human would take 10^90 years, the researchers suggested. But they also noted that there are other processes that would probably mean those objects would disappear before that time runs out.
The work is described in a new paper, 'Universe decays faster than thought, but still takes a long time', published in the Journal of Cosmology and Astroparticle Physics.