Fortunately the next one will miss usAll of a sudden, it started raining with asteroids! No wonder, astronomers estimate that there are about 7,000 such rocks, discovered and undiscovered, orbiting around the Sun and periodically coming through the vicinity of the Earth. Because they are so small in size, many less than 150 meters in diameter, astronomers can only spot them as they pass by our planet. On 11 October, last year NASA's Catalina Sky Survey discovered the asteroid 2007 TU24, with a diameter of about 150 to 600 meters, and predicted its trajectory.
On Tuesday, 29 January, amateur astronomers from all over the world will be able to see 2007 TU24 on the night sky, as it executes a fly-by around the Earth. It will fly over the planet at a distance on only 534,400 kilometers, just a little over the average orbit of our moon.
According to Don Yeomans from NEO at the Jet Propulsion Laboratory at NASA, this will be the closest approach of a large known asteroid since man began observing the movement of such objects on the sky, and it poses no danger of collision with the Earth. Its relatively large size, up to 600 meters in diameter, would permit it to penetrate all the way through the atmosphere to hit the surface. In such a scenario, the energy released during impact is estimated to be of about 1,500 megatons of TNT, which is enough to create a crater about 5 kilometers in diameter and could throw large amounts of debris in nearby areas.
An eventual distant future collision will probably send the asteroid into the ocean, since more than two thirds of the Earth's surface is covered with bodies of water, and could trigger a massive tsunami wave that would destroy the coastline settlements.
During the fly-by on 29 January, it will appear on the night sky with a magnitude of 10.3, which is equivalent to the 50 time least than the faintest objects observed with the naked eye, thus specialized equipment is required in case you want to observe it!
Most of the asteroids with periodical orbits around the Sun originate in the space between the orbit of Mars and that of Jupiter, also known as the asteroid belt, and it is estimated that once every five years one object of this kind makes a fly-by through the vicinity of Earth, while an impact would usually occur once in 37,000 years. Although most of the large asteroids coming close to Earth have been cataloged by astronomers and proven to pose no threat, there are potentially thousands of other asteroids with diameters less than 140 meters that could still inflict regional damage in case of an impact.