Fastest-Spinning Asteroid Discovered

Asteroid 2008HJ is the fastest-rotating natural object in our solar system

Speedy Asteroid

Moving almost 1,000 miles through space in less than a minute, asteroid 2008HJ (the trail of light at the center of this image) brightened considerably as it moved from right to left—evidence that the asteroid rotates rapidly, reflecting sunlight differently as it turns.Richard Miles, Golden Hill Observatory

Asteroid 2008HJ is not only a "superfast rotator," it's the fastest of the superfast. According to the British amateur astronomer Richard Miles, who clocked the asteroid using the remotely operated Faulkes Telescope South, 2008HJ makes a full rotation every 42.67 seconds—almost twice as fast as the previous record holder.

First spotted in late April, 2008HJ was visible for a few days as it passed relatively close to Earth—less than three times as far away as the moon. Just a few hours before the closest approach, Miles took a series of photographs in which the moving asteroid appeared as a trail of reflected sunlight. By measuring the fluctuations in the light's brightness as the asteroid rotated, Miles was able to calculate how fast it was spinning.

The asteroid appears to be a stony, oblong object measuring about 40 feet by 80 feet. Whizzing through space at more than 100,000 miles per hour, with no atmosphere or gravity to speak of, 2008HJ wouldn't be a pleasant place to live. And with the sun rising more than 2,000 times as frequently as it does on Earth, forget about getting a good night's sleep.