Astronomers at the University of St Andrews have pinpointed the date the world will end – and it is still five billion years away, leaving humanity ample time to enjoy a few more pints before the planet is obliterated.
Using the NASA/ESA/CSA James Webb Space Telescope, the research team watched a Jupiter-sized exoplanet called WD 1856 b transit its dead host star – a white dwarf – acting as a ‘time machine’ to peer into the future of our own solar system. They measured the planet’s mass, temperature and even detected its atmosphere, finding it ‘significantly warmer’ than expected.
“Earth will be destroyed when the sun dies in five billion years, new research confirms.”
‘The planet is quite the oddball,’ said study lead author Dr Ryan MacDonald. ‘It’s about the size of Jupiter, but the white dwarf it orbits is the size of Earth, so the planet is seven times larger than its star.’
WD 1856 b orbits its star at a distance 50 times closer than Earth orbits the sun – an ‘extremely close’ orbit that would have been impossible if the planet had been there during the star’s red giant phase. The team explained that the sun will run out of hydrogen fuel in its core in around five billion years, swelling up more than 100 times its current size into a red giant. It will then shed its outer layers and end its life as a white dwarf.
Mercury, Venus and possibly Earth will be destroyed by the red giant, according to the study published in the journal Nature. The fate of more distant planets like the gas giants remains uncertain. ‘Finding and studying planets in orbit around the remnants of Sun-like stars after their death is a way of learning what might happen in our own Solar System in the far future,’ the researchers said.
The exoplanet was first discovered in 2020 using the £216 million NASA Transiting Exoplanet Survey Satellite (TESS) and the Spitzer Space Telescope. It orbits the white dwarf WD 1856+534 about 80 light-years from Earth – a distance that would take over one million years to travel using modern rocket technology.
Dr MacDonald noted that if WD 1856 b had originally been orbiting at its current distance, it would have been obliterated while the star was a red giant. Will Earth’s fate echo that of its distant cousin?