A double asteroid that zipped past Earth last month had been captured on camera by astronomers.

The European Southern Observatory (ESO) took an image of the double asteroid dubbed 1999 KW4 with its Very Large Telescope (VLT) when the space rocks made a "close" pass of Earth at a distance of around 5.2 million miles on May 25. Specifically, the SPHERE instrument on the VLT made it possible to capture the sharp image and show both halves of the double asteroid, according to a statement on ESO's website.

Measuring only 1.3 kilometers in diameter, 1999 KW4 had not been considered a potential threat to Earth.

The incredibly detailed image obtained by the VLT showed the two distinct objects that make up the 1999 KW4. Unlike most other space rocks that zoom past our planet, the latest object to make a close approach to Earth is actually two separate rocks.

One of the space rocks comprising the double asteroid is larger than the other and is considered the main body at about a mile in diameter. On the other hand, the second "asteroid moon" that orbits it is only a fraction of its size, though still considered relatively large at a quarter mile in width. The two formations are not attached to each other and are actually separated by a distance of about 2.6 kilometers.

The actual photo taken by the VLT appears hazy and shows only blurred lights, however, the ESO also released an artist's interpretation of what the double asteroid may actually look like.

Asteroid
The left-hand image shows SPHERE observations of Asteroid 1999 KW4. The angular resolution in this image is equivalent to picking out a single building in New York — from Paris. An artist's impression of the asteroid pair is shown on the right. ESO

The ESO had not been the only organization observing the asteroid, as well as other Near-Earth Objects (NEO). The International Asteroid Warning Network (IAWN) was behind the observing campaign last month which the ESO took part in.

The IAWN and ESO hope to improve the Earth's defenses against asteroids and other NEOs that would possibly crash into the planet by studying the observations made on the space rocks that have been zipping by.

“These data, combined with all those that are obtained on other telescopes through the IAWN campaign, will be essential for evaluating effective deflection strategies in the event that an asteroid was found to be on a collision course with Earth,” ESO astronomer Olivier Hainaut said in a statement. “In the worst possible case, this knowledge is also essential to predict how an asteroid could interact with the atmosphere and Earth’s surface, allowing us to mitigate damage in the event of a collision.”