Homecoming rocket disaster proves a theory too far

A discarded rocket section crashing into Earth and causing major damage would have made for a great story. Unfortunately for journalists, and fortunately for the rest of us, that’s not what happened today.

An asteroid discovered on Monday and named 2010 AL30 caused some brief interest thanks to a couple of intriguing features. It was somewhere around 36 feet (11 meters) wide and was calculated to be orbiting the Sun on a cycle of not far off one Earth year. That created some briefly held theories that the object might be man-made.

However, that idea was rejected yesterday by NASA’s Paul Chodas who noted that the trajectory of the asteroid didn’t match up with that used for spacecraft departing the Earth. He also noted there were no signs of other objects following behind the asteroid, which might have been expected with man-made space debris. And he also calculated that the asteroid would have been nowhere near Earth during the launch periods of most major space missions.

It seems most likely then that the one-year orbit cycle is just a coincidence. In the event, the asteroid passed the Earth today at a distance of around 80,000 miles (130,000 kilometers). That put it near enough to be viewable by amateur photographers and the general attitude of space experts seems to be that the distance was notable but not particularly unusual.

Had the asteroid hit Earth, it wouldn’t have been much fun if it landed on your house. But in any case, it wasn’t classed as a serious risk: that label is limited to asteroids of at least 100 meters in diameter. Indeed, assuming 2010 AL30 was a stony asteroid, it would most likely have burnt up in Earth’s atmosphere anyway.