Asteroid 2011 AG5 May Pose Threat to Earth in 2040

Scientists are keeping a close eye on a big asteroid that may pose an impact threat to Earth in a few decades.
The space rock, which is called 2011 AG5, is about 460 feet (140 meters) wide. It may come close enough to Earth in 2040 that some researchers are calling for a discussion about how to deflect it.
Talk about the asteroid was on the agenda during the 49th session of the Scientific and Technical Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS), held earlier this month in Vienna.
A UN Action Team on near-Earth objects (NEOs) noted the asteroid’s repeat approaches to Earth and the possibility — however remote — that 2011 AG5 might smack into our planet 28 years from now.
The object was discovered in January 2011 by Mount Lemmon Survey observers in Tucson, Ariz. While scientists have a good bead on the space rock's size, its mass and compositional makeup are unknown at present. [The 7 Strangest Asteroids in the Solar System]
An asteroid desktop exercise

"2011 AG5 is the object which currently has the highest chance of impacting the Earth … in 2040. However, we have only observed it for about half an orbit, thus the confidence in these calculations is still not very high," said Detlef Koschny of the European Space Agency’s Solar System Missions Division in Noordwijk, The Netherlands.