As the strangely-shaped space rock was making its way safely past Earth accompanied by its very own moon, astronomers using ESO’s VTL Observatory in Chile managed to snap an image as it passed by us.
On May 25, 1999 KW4, an asteroid about 1.3 km wide orbited by a 0.5 km wide satellite, passed close to Earth at around 70,000 kilometers per hour.
The image was taken thanks to unique capabilities of the SPHERE instrument on ESO’s Very Large Telescope which enabled it to get the sharpest images of a double asteroid as it flew past Earth.
Interestingly, SPHERE wasn’t designed to observe asteroids. The instrument on the VLT was actually built to observe exoplanets. It has a state.of-the-art adaptive optics systems with are able to correct turbulence present in Earth’s atmosphere, allowing the telescope to deliver images nearly as sharp as if the telescope was located in space.
It also has the ability to dim the glare of extremely birth stars, allowing the exposure of faint orbiting exoplanets.
While the odd asteroid was not itself a threatening object for our planet, scientists made use of the opportunity to rehearse the response to a hazardous Near-Earth Object (NEO), proving that ESO’s front-line technology could be critical in planetary defense, reports the European Southern Observatory.
“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,” explained ESO astronomer Olivier Hainaut.
“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.”
“The double asteroid was hurtling by the Earth at more than 70 000 km/h, making observing it with the VLT challenging,” revealed Diego Parraguez, who was operating the telescope.
Parraguez made use of all his expertise and knowledge to be able to lock onto the asteroid and snap an image of it with SPHERE.
“During the observations, the atmospheric conditions were a bit unstable. In addition, the asteroid was relatively faint and moving very fast in the sky, making these observations particularly challenging, and causing the AO system to crash several times. It was great to see our hard work pay off despite the difficulties!” revealed Mathias Jones a VLT astronomer who participated in the process.