A tiny space rock that’s partially tethered to Earth by a gravitational leash is our planet’s first known Trojan asteroid, astronomers say. This space rock is about 1000 feet wide and about 50 million miles in front of Earth in our shared orbit. We share the same orbit, but will never collide.
Trojan asteroids have been found around Jupiter, Neptune and Mars. The total number of Trojan asteroids larger than 1 km is believed to be about 1 million. Trojans are thought to have been captured into their orbits during the early stages of the Solar System’s formation or slightly later.
One scientists likens the odd asteroid to an orange held at arm’s length by a person riding a Ferris wheel. In this analogy, the orange is the Trojan, the person is Earth, and the Ferris wheel is our orbit around the sun. “The orange would be going around the Ferris wheel, but maintaining it out at arm’s length is up to you,” Connors explained.
Even though the Trojan asteroid is relatively close to Earth, it is not a good candidate for future exploration because it follows an unusual tilted path in relation to Earth’s. This makes it either too far above or below the plane of Earth’s orbit and getting to the Trojan would require huge amount of fuel.
For more information