The asteroid that flew past Earth on Monday was not traveling alone. As you can clearly see in the image above, it was accompanied by its very own mini-moon.
The picture was taken by NASA's Deep Space Network antenna at the Goldstone complex in California.
The radar images also reveal that the asteroid known as 2004 BL86 is about 1,100 feet across, or nearly the length of four football fields.
The smaller asteroid, or moon, that orbits the larger body is 230 feet across, about the size of the Statue of Liberty and her pedestal.
It is not completely unexpected to see an asteroid flying through space with its own little moon in tow.
About 16% of near-Earth asteroids 665 feet across or bigger have at least one smaller asteroid orbiting it -- what is known as a binary system, according to a release from NASA's Jet Propulsion Laboratory.
Some asteroids are in triple systems and have two moons.
Asteroid 2004 BL86 was 745,000 miles from Earth at its closest approach Monday at 8:19 a.m. PST. That is about triple the distance between the Earth and the moon.
The asteroid was discovered in January 2004, giving astronomers plenty of time to observe it and understand its trajectory. There was never any fear that it would hit the Earth, but scientists say it is the closest a known asteroid this big will come to our planet until 2027.
The asteroid's next brush past the Earth is expected to occur 200 years from now -- hopefully its little friend will still be with it.