Astrophysicists Puzzle Over Planet That’s Too Close to its Sun

Scientists have discovered a planet that shouldn’t exist. The finding, they say, could alter our understanding of orbital dynamics, a field considered pretty well settled since the time of astronomer Johannes Kepler 400 years ago. The planet is known as a hot Jupiter, a gas giant orbiting the star Wasp-18, about 330 light-years from Earth. The planet, Wasp-18b, is so close to the star that it completes a full orbit (its year) in less than an Earth day. Of the more than 370 exoplanets — planets orbiting stars other than our sun — discovered so far, this is just the second with such a close orbit