The end of the Universe might come sooner than previously suggested, although it will still be far into the future
New research by a team at Radboud University in the Netherlands shows that the cosmos is decaying faster than once thought; this discovery was made through new understandings of Hawking radiation.
This study, published in the Journal of Cosmology and Astroparticle Physics, suggests that even the most enduring remnants of stars, such as white dwarfs and neutron stars, will eventually vanish due to a slow, quantum-based radiation process. And while “soon” is a relative term in cosmic timescales, the newly calculated end, at about 10^78 years, is much earlier than the estimated 10^1100 years.
A new understanding of Hawking radiation
The concept at the centre of this research is Hawking radiation, a theory proposed by physicist Stephen Hawking in 1975.
It states that black holes can slowly lose mass and energy through quantum effects near their event horizons. Over long periods, this process causes black holes to evaporate completely.
The Radboud team has now found that this type of radiation doesn’t just apply to black holes. Their detailed calculations reveal that all dense celestial objects, including neutron stars and white dwarfs, may emit Hawking-like radiation. Eventually, even these stellar corpses will fade away.
Evaporation by density
One of the study’s most surprising findings is that the evaporation time of an object depends on its density, not just its gravitational strength. This led to a particularly unexpected find: neutron stars and stellar black holes are predicted to take roughly the same amount of time to disappear, about 10^67 years.
This seems counterintuitive because black holes have far more intense gravitational fields. However, the researchers explain this by noting that black holes lack a surface, which allows them to partially reabsorb some of the radiation they emit, slowing their decay compared to what density alone would suggest.
The researchers also extended their calculations to smaller objects, like the Moon and even a human body. According to their models, either would take approximately 10^90 years to vanish through Hawking-like radiation. This assumes no other forms of decay, destruction, or transformation occur first, which, in the case of humans, is a safe assumption.
An interdisciplinary approach to the Universe’s fate
The research was a collaboration among astrophysics, quantum physics, and mathematics experts. It builds on a 2023 study by the same group, which first proposed that Hawking radiation could affect more than just black holes. Responding to questions sparked by that earlier work, the scientists set out to calculate how long this radiation would take to erase all matter in the Universe.
The team has opened new doors to understanding how the Universe may ultimately end by rethinking old assumptions and examining extreme scenarios.
And while 10^78 years is a dramatic shortening of the timeline, it’s still a long way off.
