See the funky double asteroid that zipped by Earth

A lot of asteroids pass by Earth, goal 1999 KW4 moseyed with a little something extra: its own moon.

The double asteroid reached its closest approach on May 25th and the European Southern Observatory managed to snag some snapshots.

ESO released an image of the asteroid on monday an artist's impression of what it might look like. The real image looks like a couple of fuzzy blobs, but it shows the distinctly double nature of the asteroid.

The exoplanet-spotting SPHERE instrument on the ESO'S Very Large Telescope in Chile is extremely sensitive. ESO says it's "one of the few instruments in the world capable of obtaining images sharp enough to distinguish the two components of the asteroid." The larger body and the smaller one are 1.6 miles (2.6 kilometers) away. SPHERE stands for Spectro-Polarimetric High-contrast Exoplanet REsearch.

Asteroid 1994 KW4 is classified as "potentially hazardous," though it did not pose a threat to Earth. It's a very safe distance away. ESO used the asteroid as a test of the International Asteroid Warning Network. Multiple organizations coordinated on an observation campaign.

Researchers aim to learn more about passing asteroids so we can better understand how to deflect dangerous rocks or mitigate damage from impacts. Asteroid 1994 KW4 is particularly intriguing because it resembles another binary asteroid named Didymos that could threaten Earth in the distant future.

NASA is working on its Double Asteroid Redirection Test to Didymos where it will crash into the asteroid's moonlet in 2022 and try to knock it out a little off course. It sounds like a sci-fi movie, but NASA hopes it will show that asteroids could potentially be nudged away from Earth.

Studying harmless 1994 KW4 is one more key step in preparing for battle with asteroids.