For the first time astronomers think they have measured the rotation rate of an exoplanet, thus determining the length of its day.
Ignas Snellen and his colleagues at Leiden University in the Netherlands report in Nature1 that a gaseous planet orbiting the star β Pictoris rotates at 25 kilometres per second at its equator — faster than any planet in the Solar System and about 50 times faster than Earth. A day on the planet, called β Pictoris b, lasts just over eight hours, even though the planet has a diameter more than 16 times that of Earth’s and carries more than 3,000 times Earth’s heft.
This result falls under my category of “the uncertainty of science.” Though quite cool, and based on real data, the uncertainties are great. Don’t bet the house that this result will stand up to closer observations in the future.