New study shows universe's decay may be faster than previously estimated

The universe may be decaying much faster than previously thought, according to recent calculations on the so-called Hawking radiation by three scientists at Radboud University.

Their research suggests that the last stellar remnants take about 10^78 years (1 with 78 zeros) to perish. This is a dramatic reduction from the earlier postulation of 10^1,100 years (1 with 1,100 zeros). The findings have been published in the Journal of Cosmology and Astroparticle Physics.

Hawking radiation, a theory developed by renowned physicist Stephen Hawking, is black-body radiation released outside a black hole's event horizon. One of the consequences of this so-called Hawking radiation is that a black hole very slowly decays into particles and radiation.

In 2023, the research team of the university published a paper revealing that not only black holes, but also other objects like neutron stars can "evaporate" through a process similar to Hawking radiation. Following its publication, the researchers received many questions about how long the process would take.

In their latest study, the scientists calculated that the end of the universe is about 10^78 years away, when considering only Hawking-like radiation. This is the time required for white dwarf stars, the most persistent celestial bodies, to decay via Hawking-like radiation. Previous studies, which did not take this effect into account, estimated the lifetime of white dwarfs to be 10^1,100 years.

"So the ultimate end of the universe comes much sooner than expected, but fortunately it still takes a very long time," said Heino Falcke, lead author of the paper.

They also calculated how long it would take for the moon and a human to evaporate via Hawking-like radiation. The result is 10^90 years (1 with 90 zeros). But the researchers pointed out that other processes might cause the moon and humans to disappear more quickly than calculated.