Asteroid 2013 RZ53 — a small asteroid from the Apollo family of near-Earth asteroids, a relative of the meteor that exploded over Russia earlier this year — passed within only about 148,000 miles of the Earth last night. The tiny asteroid — only three to ten feet across — made its closest approach to the Earth at about 6:20 pm EDT on Wednesday September 18, 2013. While the asteroid is from the same group as the Chelyabinsk meteor, it is much smaller, and as a result doesn’t pose the same sort of threat.
Asteroid 2013 RZ53 was first observed less than a week ago — astronomers first caught sight of the space rock on Friday September 13, 2013, according to data from the Minor Planet Center.
Space.com has more:
Even if it were aimed directly at our planet, the newly discovered space rock is so small that it would likely burn up in the atmosphere before it could hit the ground. By observing the asteroid over several days, researchers pieced together its trajectory. They also put together an animation of asteroid 2013 RZ53’s path, showing that it comes relatively close to Earth’s orbit.
The space rock belongs to the Apollo family of near-Earth asteroids — the same group from which the meteor that exploded over the Russian city of Chelyabinsk in February 2013 is thought to have originated. The Russian meteor was much larger than the newly discovered asteroid, estimated to have been about 56 to 66 feet wide before it exploded.
The discovery of 2013 RZ53 was made by researchers with the Mount Lemmon Survey at the University of Arizona. The project is part of a larger, NASA-sponsored program called the Catalina Sky Survey, which scans the cosmos for potentially dangerous asteroids. NASA and its partners keep tabs on asteroids and comets that fly near the planet as part of the Near-Earth Object Observations program, which uses a network of ground-based and space telescopes to monitor potential threats.
Interesting that the new asteroid was discovered only a couple of days before its pass-by — not much of a warning system really.