The discovery of a planet that is far too massive for its sun is calling into question what was previously understood about the formation of planets and their solar systems, according to Penn State researchers.
In a paper published in the journal Science, researchers report the discovery of a planet more than 13 times as massive as Earth orbiting the “ultracool” star LHS 3154, which itself is nine times less massive than the sun. The mass ratio of the newly found planet with its host star is more than 100 times higher than that of Earth and the sun.
The finding reveals the most massive known planet in a close orbit around an ultracool dwarf star, the least massive and coldest stars in the universe. The discovery goes against what current theories would predict for planet formation around small stars and marks the first time a planet with such high mass has been spotted orbiting such a low-mass star.
In the mind-bogglingly unlikely event that a Venus-sized object was on a collision course with Earth, I’d guess we’d likely have a couple of years’ warning. Maybe a decade. It’s not easy to detect objects out beyond Neptune, even when they’re sizeable.
The odds are so incredibly small that they’re not worth worrying about even abstractly, IMO. The Solar System has gone for 4.5 billion years without any of the Terrestrial planets in it being smacked by a rogue planet (I suppose it’s possible one of the gas giants might have swallowed a small one in the distant past, though even then I’d expect signs of such an event to remain on its moons) so the chance that one might happen to come along right at this instant in time is vanishingly small.