NASA Discovers Earth’s Sidekick: A Trojan Asteroid
Now there’s word out of NASA’s Jet Propulsion Laboratory that astronomers have just discovered Earth’s first Trojan asteroid — a rock that shares our own solar orbit, leading us around the sun like a tugboat pulling an ocean liner. That’s big news not just because such an object had never been spotted before, but also because a Trojan could make such an easy and nifty place for astronauts to visit.
Trojan asteroids have been seen in the solar system before: Mars has one, so does Jupiter, so does Neptune and so do two of Saturn’s moons. There was no reason Earth couldn’t have one too, but they’re not easy to detect because of both their small size and the telescope-swamping effects of the sun. (Through a complicated — and unfortunate — interplay of Trojans’ Earth-leading position and the rotation of the planet itself, the asteroids tend to appear in the skies mostly during daylight hours.)