A report in Nature says that scientists have discovered a planet that survived the red giant expansion stage of its sun on the star’s way to becoming a white dwarf.
The planet, about three times the mass of Jupiter, orbits V 391 Pegasi. During the red dwarf phase of its star’s life it was roughly 1 AU from the star (i.e.: the distance Earth currently is from our sun). The planet currently orbits V 391 Pegasi at a distance of about 1.7 astronomical units (AU), or about 158 million miles (a bit further out than Mars currently orbits the sun).
This is of interest to scientists because (as the NY Times explains): “When our own Sun [roughly similar V 391 Pegasi] begins to graduate from a hydrogen-burning main sequence star to a red giant, two effects will compete…As the Sun blows off mass to conserve angular momentum, Earth will retreat to a more distant, safer orbit. At the same time, tidal forces between Earth and the expanding star will try to drag the planet inward, where it could be engulfed.”
So the ultimate fate of Earth has always been in question. It now appears, given the experience of the gas giant in V 391 Pegasi, that maybe Earth can avoid such a calamity, too…5 BILLION YEARS FROM NOW.
As much fun as thinking about 5 billion years from now is, and as much as it adds to our understanding of the universe, can we get back to stopping global warming now, please? Because if we don’t we’re not going to last 500 years let alone 5 billion.