We are not alone - a small asteroid, 1,000 feet across, has finally been found and it's orbital path shares Earth's orbit.

2010 TK7 teases Earth by straying in the planet's orbit but at the same time is about 50 million miles ahead of Earth. This is the first of the so-called Earth's Trojan asteroids, a family of space rocks so called because they share the same orbit as the Earth but is always far away enough so as not to collide with the planet.

2010 TK7 was discovered last year by the astronomers from Athabasca University, UCLA, and University of Western Ontario, who used NASA's Wide-field Infrared Survey Explorer (WISE) satellite and ground-based telescopes but it was only recently that it was determined as a Trojan asteroid. Their work was published in Nature magazine on Wednesday.

Discovery of 2010 TK7 is significant because Trojan asteroids, scientists believe, may hold elements rare on Earth's surface. Moreover, Martin Connors of Athabasca University said Trojan asteroids sometimes range so far ahead that they're on the opposite side of the sun from Earth. Besides spotting one in Earth's orbit becomes difficult from the ground because they are generally up in the daytime sky.

In an interview with The Vancouver Sun, Connors said he had been hunting for an Earthly Trojan for almost 20 years and was ecstatic when he finally discovered one.

However, despite the name 'Trojan', 2010 TK7 is harmless. "On timescales of hundreds of thousands of years, this particular object would not be a threat," he said.

There are thousands of Trojan asteroids in our solar system - a few have been found for Mars and Neptune and nearly 5,000 for Jupiter.

Earth Asteroid