The asteroid 19 Apophis, first discovered on June 2004, 99942, was until recently considered potentially dangerous for the Earth. This space body 340 meters long and weighing about 61 million tons could collide with our planet in one of the flights. The blow would have been akin to the explosion of a two-megaton bomb, so Apophis was monitored from the moment it was discovered. New data made it possible to exclude this asteroid from the list of dangerous for the Earth for at least a hundred years.

The trajectory of the passage of the asteroid Apophis past the Earth in 2029. Image Source: NASA / JPL-Caltech

Once again, Apophis flew past the Earth on March 5 this year at a distance of about 17 million km. Each new span made it possible to better and better determine the trajectory of the object. This time, the asteroid was monitored by a radar in Goldstone (California) and a 100-meter radio telescope at Greenbank Observatory (West Virginia). The signal sent by the radar bounced off the asteroid and was caught by the radio telescope. The measurement made it possible to clarify the trajectory of Apophis’ movement and to calculate with sufficient accuracy the distance of approach to the Earth in future passages: in 2029, 2038 and 2068.

Refined data show that in this century, all subsequent passages of Apophis near the Earth will have zero probability of collision. For example, on April 13, 2029, the asteroid will pass at a distance of 32 thousand km from the Earth, which has already been precisely determined. There is no more threatening scatter and uncertainty in the calculations, and the asteroid is excluded from the catalog of objects dangerous for the Earth.