Last week, an asteroid the size of a 20-story building flew dangerously close to Earth, speeding by our planet at a distance about equal to that between Earth and the moon. Astronomers didn’t spot the asteroid until two days later.
The 200-foot-wide (60-meter) space rock, now known as 2023 NT1, passed by Earth on July 13 at a speed of about 53,000 miles per hour (86,000 kilometers per hour), according to NASA. However, because the asteroid approached from the sun’s direction, telescopes weren’t able to see it coming until it had already past.
The building-sized rock was unknown to astronomers until July 15, when it was spotted leaving our neighborhood by a telescope in South Africa that is a part of the Asteroid Terrestrial-impact Last Alert System (ATLAS), a network of telescopes designed to detect asteroids days to weeks before any potential impact. The rock was soon discovered by more than a dozen additional observatories, according to the Minor Planet Center of the International Astronomical Union.
More than 31,000 known near-Earth asteroids are being actively watched by astronomers, but they are also well aware of the risks posed by the solar blind area. The European Space Agency is working diligently on the NEOMIR mission to counter this threat. The spacecraft will travel between Earth and the sun around the year 2030 in an effort to find huge asteroids that may be obscured by our star’s brightness.