The potentially hazardous asteroid 4179 Toutatis, discovered on January 4, 1989, is a main belt asteroid belonging to the Apollo class of asteroids. Apollo asteroids are Earth crossers which have a perihelion distance (closest to the Sun distance) that is less than 1 a.u. (astronomical unit - 93,000,000 miles). The asteroid made its closest approach to Earth on September 29, 2004, when it came within 0.0103572 a.u. It's next close approach will be on November 9, 2008 when it will be 0.0502479 a.u. from the Earth. The asteroid has been measured, using radio astrometry, to be approximately 2.8 km in diameter.

In these two images, taken a little more than six minutes apart, the asteroid's motion across the sky is evident. When these images were taken the asteroid was 0.0366 a.u. (3.4 million miles) away.