A tiny asteroid, having roughly the same orbit as the Earth, has been discovered. The companion asteroid is about 300 yards across. It leads the Earth as both the objects orbit the Sun. However, the asteroid has variable speed and a more eccentric orbit, often leading the Earth by as much as half-an-orbit.
The finding is due to work by Martin Connors of Canada’s Athabasca University and his colleagues. The findings have been published in the journal Nature.
The new object
The asteroid has been named 2010 TK7, and was discovered last year by NASA’s WISE satellite. This is the first time such a companion rocky body has been discovered to share the orbit with Earth. Many such bodies are known to either share the orbit with Jupiter or Saturn or become their moons. In fact, the fate of many objects sharing orbits with such large planets is that they eventually become satellites.
Asteroids are giant rocks in space, orbiting the Sun, believed to be remnants of the planet forming era. These are leftovers, those chunks which did not form planets. Among the big asteroids in the Solar System is Ceres, which has its own orbit between Mars and Jupiter. It is believed to be remnants of a planet which broke up, probably after being struck by a large comet.
Earth is not alone
Rocky bodies which share an orbit with a planet are called Trojans’. This object 2010 TK7 is the first Trojan found for Earth. Jupiter is known to have about 5000 Trojans, rocks brought to it by its intense gravitational pull. Mars, Neptune and Saturn also have their share, though the number is much less than that of Jupiter.
There is no fear of an asteroid crashing onto the Earth in the immediate future. It’s just a harmless body accompanying the Earth on its annual journey around the Sun.