Fast Day

Some planets spin quickly, while others turn a bit more slowly. Earth is in the “quick” category, so a day on our planet lasts just 24 hours. Astronomers recently found a planet in another star system that spins even faster. In fact, it spins faster than any of the planets in our own solar system.
The planet is a gas giant that orbits Beta Pictoris, a star that’s more than 60 light-years away.
As the planet turns on its axis, one side moves toward us while the other side moves away from us. Light from the planet’s approaching hemisphere is shifted to shorter, or bluer, wavelengths, while light from the receding hemisphere is shifted to longer, redder wavelengths. Measuring that shift revealed that the planet rotates once every eight hours.
By comparison, the whirling dervish of our own solar system is Jupiter, which spins once every 10 hours.
The new finding extends a correlation between how massive a planet is and how fast it spins. In our solar system, all of the planets that are mor