2002 AA29

On January 8, 2003, the asteroid came within approximately 5.9 Gm (3.7 million miles) of Earth, its closest approach for almost a century.

The asteroid spends most of its time following a "horseshoe orbit" that makes it come near the Earth every 95 years as it follows Earth's orbit around the Sun. In about 600 years, it will appear to circle Earth in a quasi-satellite orbit. Calculations suggest was in such a quasi-satellite orbit between about 550–600 A.D. but would have been too small to be observed visually then.

J. Richard Gott and Edward Belbruno from Princeton University have speculated that might have formed together with Earth and Theia, the postulated planet that, according to the Giant Impact hypothesis collided with Earth in its early history.

The orbit of the asteroid is such that it would be relatively easy for a spacecraft to retrieve rock samples from it and bring them to Earth for analysis.

See also

• Co-orbital moon
• Natural satellite
• Quasi-satellite
• Horseshoe orbit

External links

• MPEC 2003-A17
• Earth coorbital asteroid
• Research paper describing horseshoe orbits. Recommend starting at page 105!