Earth’s second moon
The WISE telescope has spotted an asteroid in earth’s orbit. It’s about 200 to 300 metres (+-1,000 feet) wide and because of its gravitational location, it poses no threat to the earth.
It’s been classified as a trojan asteroid. Defined by National Geographic as “Trojans are objects that exist in gravitationally stable regions in front of or behind another body, so that the two share the same orbit but never collide.”
Trojan asteroids could be considered as an option for space missions. However, this newly discovered one, called 2010 TK7, is a bit too far to be of practical use in that way – for now at least. So the hope is that there may be more, closer to us, that we have yet to discover.
The predictions are that this newly discovered asteroid’s orbit will be stable for at least another ten thousand years. Perhaps in that time we’ll have developed an easier and cheaper method of space travel.
For further reading see this BBC and a National Geographic article on this topic.