The asteroid, which was first discovered by the Lincoln Near-Earth Asteroid Researcher (LINEAR) astronomical survey in Socorro, New Mexico, in 1999, is estimated to measure somewhere between 0.8 miles to 1.86 miles in diameter, according to NASA's JPL.
The monster-sized asteroid - with the catchy name of 1999 KW4 - is so big it has its own moon orbiting it. The small moon-which orbits at a distance of 1.6 miles every 16 hours-is thought to be around the third of that size, EarthSky reported.
1999 KW4 has been classified as a Near Earth Object (NEO), a term that refers to any asteroid or comet whose orbit takes it within 121 miles of the sun, as well as within approximately 30 million miles of Earth.
"It is slightly squashed at the poles and with a mountain ridge around the equator, which runs all the way around the asteroid".
The last time the asteroid approached the Earth fell on the afternoon of May 27, 2018.
The asteroid also has a.3-mile-wide "companion" asteroid, which experts are calling an "asteroid moon" in orbit. It is believed that the YORP effect is also one of the causes for the creation of binary asteroids such as the 1999 KW4.
The European Space Agency released a brief animation of the approaching system captured from an observatory on Reunion Island in the Indian Ocean on May 9.
A binary asteroid system, a almost mile-wide asteroid with its own moon, will pass within 3.5 million miles of Earth this weekend, and while there is no direct threat, it is still the largest asteroid to pass within the range considered to be "potentially dangerous" this year.