A fact to make your head spin: A distant planet has been discovered rotating on its axis three times as fast as earth, creating a day that is only eight hours.
Astronomers with the European Southern Observatory report they've made the first determination of the rotation speed and rate of an exoplanet far outside our solar system, a world dubbed Beta Pictoris b.
The giant gas planet similar to Jupiter but 10 times as large, orbits its host Beta Pictoris. Fairly close to us at 65 light years distance and observable by the naked eye in Earth's southern hemisphere in the constellation Pictor, also known as the Painter's Easel.
Orbiting its star at just eight times the distance of the Earth from the Sun, it is the closest example of an exoplanet to its host star ever directly imaged, the Dutch astronomers making the discovery say.
The planet is some 16 times bigger than Earth with 3,000 times the mass of our planet, yet its 29,200 equatorial rotational speed dwarfs Earth's 1,000 mph velocity or that of any other planet in our own solar system.
"It is not known why some planets spin fast and others more slowly," says Remco de Kok of the Netherlands Institute for Space Research, "but this first measurement of an exoplanet's rotation shows that the trend seen in the Solar System, where the more massive planets spin faster, also holds true for exoplanets."
"This must be some universal consequence of the way planets form," says de Kok, co-author of the Beta Pictoris b study.
The study of Beta Pictoris and its planet was conducted using the ESO's Very Large Telescope in Chile.
As short as the planet's day is, it will probably get even more brief as the relatively young planet -- only 20 million years old, compared to our world's 4.5 billion years -- cools and shrinks, increasing its rate of spin significantly, the astronomers say.
The high rotation rate for a large planet is seen in our own solar system, they emphasize, where the more massive worlds like Jupiter -- with its 10-hour "day" -- and Saturn, Uranus and Neptune tend to rotate at a faster rate than the smaller rocky worlds.
As more and more is learned about exoplanets, the more we can know about our own solar system, the researchers said.
"Only if we know more about other planets ---like temperatures, atmosphere and rotation -- can we tell how unique our home in the universe really is," University of Leiden astronomy Professor Bernhard Brandl says.
