An asteroid that could be as big as the Chrysler Building is set to fly safely past Earth this weekend.
The space rock, known as 2013 CU83, is predicted to make a close approach to our planet. According to figures from NASA‘s Center for Near Earth Studies database, the asteroid will come within around 4.3 million miles of Earth at 11:37 p.m. UTC, or 7:37 p.m. ET, on Saturday.
To place this close approach into context, 4.3 million miles is roughly equivalent to 18 times the average distance between the Earth and the moon. While this may sound like a large distance, on the scale of the solar system, astronomers consider it to be a close approach. But the trajectory of this object is well known and there is zero chance that 2013 CU83 will collide with our planet this time around.
Asteroids are rocky objects that orbit the sun, much like planets, although they are significantly smaller.
These space rocks vary in size dramatically. The largest known asteroid is Vesta, which measures around 329 miles across. But most asteroids are much smaller, with some measuring less than 33 feet across.
To date, more than 1.1 million asteroids have been identified, according to NASA, most of which can be found in the main asteroid belt located between the orbits of Mars and Jupiter.
As it makes its close approach to Earth, 2013 CU83 will be traveling at speeds of around 13,100 miles per hour, which is more than six times faster than a rifle bullet, or seventeen times faster than the speed of sound, the CNEOS figures show.
The size of the asteroid is estimated to be anywhere between 459 feet and 1,050 feet across based on its observed magnitude in the sky. At the upper end of this size range, 2013 CU83 would stand roughly as tall as the Chrysler Building in New York City.
Estimating the size of asteroids can be challenging for astronomers, hence why the CNEOS provides a range.
“Measuring the sizes of distant objects in space is difficult,” Greg Brown, an astronomer at Royal Observatory Greenwich in the United Kingdom, told Newsweek in May. “Because often we are not able to physically see how big it is—they often appear as unresolved dots in telescopes—astronomers are often left to work out how big it is via how bright it appears.”
“The bigger it is, the more light it will reflect and thus the brighter it will seem,” he said. “However, this requires an assumption of how reflective the material it is made from is, which can vary greatly. Add on a number of other complications and the actual size of an object can be very different from the calculated value.”
2013 CU83 is one of more than 29,000 near-Earth objects, or NEOs, that scientists have discovered to date—the majority of which are asteroids. The term is used to refer to any astronomical body that passes within around 30 million miles of our planet’s orbit.
