1999 KW4 Will Pass Near Earth Tonight

A large asteroid with its own small moon will pass close to Earth after midnight tonight. This asteroid and its moon, called 1999 KW4, will travel at an interesting right angle.

The two asteroids will be closest to Earth at 2:05 a.m. (May 26) when they will be just 5,182,015 km from the planet’s surface. Discovered in 1999, this transit of the asteroids won’t actually be the closest observed since they were discovered. This will be their fourth approach to Earth since their discovery. Astronomers plan to take radar images of the asteroids as they pass.


According to NASA, these asteroids approached Earth on May 25, 2001, at a distance of 6.7% (4,836,798 km) more than they would approach this time. Seventeen years later, on May 25, 2036, the asteroids will pass 55.2% closer to Earth (2,233,106 km).

According to NASA, the 1999 KW4 is approaching 0.05 AU several times per century to Earth. The ‘AU’ denotes ‘astronomical units’, a unit equal to the distance between the earth and the sun. 0.05 AU is equal to one-twentieth the distance between the Earth and the Sun (7,480,000 km).

Asteroids will appear most clearly in the Southern Hemisphere when they reach their closest distance. The two asteroids will remain visible for several days and will be visible near the constellation Hydra on the evening of May 27 in the Northern Hemisphere.

Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *