Another day, another new exoplanet acting funny and inspiring headlines that portend the death of physics. This week in Nature, astronomers reported a pretty cool find: WASP-18b is 10 times the mass of Jupiter, 50 times closer to its star than the Earth is to the Sun, and whizzes around its star in less than a day. So how can something so big dart around so close to its star?
There are a few explanations: A) the planet might have been caught “moments” (about a million years) before its plasmatic death; B) the star WASP-18 may exert weaker tidal forces than we’d expect; or C) we need to rewrite the laws of physics.
How about…C? Both the LA Times print edition and the Independent declare that the planet “Defies the Laws of Physics” (the Times’ website has a more toned-down version, describing the situation as a “puzzle”), and Scientific American claims the planet “”https://www.scientificamerican.com/podcast/episode.cfm?id=new-exoplanet-shouldnt-exist-09-08-27">Shouldn’t Exist", though to be fair, so did the Nature press release.
On a more scientific note, scenario A seems more likely than B, and a number of news stories provide a fair breakdown of the two (AP, Science, National Geographic). Option B is more tantalizing, and some articles quote the paper’s accompanying perspective, where astronomer Douglas Hamilton noted that the odds of discovering a planet at the brink of death was “only about 1 in 1,000”. But that really doesn’t seem like too long a shot, especially since atronomers have discovered almost 400 planets.
Even if B is true, that just means there’s more to learn about tidal interactions — not about the laws of physics.