Asteroids frequently frustrate astronomers observing these space rocks. Once an asteroid is detected, space scientists must rush to take some measurements to narrow down its orbit before disappearing, for period potentially lasting decades. When an asteroid is discovered to have even a remote possibility of slamming into our planet, highly-detailed measurements are understandably necessary. Such “astrometric: data improve our understanding of the asteroid’s trajectory and refine the risk the space rock poses.
However, the case of asteroid 2006 QV89 is so far unique.
The distant space rock was discovered in August 2006, where it was observed for only ten days.
These observations indicated the asteroid had a 1-in-7,000 chance of hitting Earth on September 9 this year.
After the tenth day, the asteroid was unobservable and has not been seen since.
Now, after more than a decade, we can predict its position with only very poor accuracy.
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It is consequently extremely difficult for astronomers to observe it again, as no-one is sure where it is.
Regardless there is an ingenious method of getting the information needed.
While ESA scientists do not know 2006 QV89’s exact telemetry, they do know where it would appear in the solar system if it were on a collision course with Earth.
Therefore, this small area of space is under surveillance to check the rogue asteroid is not there.
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This method is our best chance to indirectly exclude any risk of an impact, even without actually seeing the asteroid.
This is precisely what ESA and the European Southern Observatory did on July 4 and 5, using the ESO’s Very Large Telescope (VLT).
Scientific teams obtained very “deep” images of a small area in the sky, where the asteroid would have been located if it were on track to impact Earth in September.
The resulting image above shows the region of the sky where asteroid 2006 QV89 would have been seen if on a collision course with Earth this year.
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Three red crosses reveal the specific locations, where the asteroid could have appeared as a single, bright, round source, had it been on a collision course.
Even if the asteroid measured only a few metres across, it would have been seen in the image.
Any smaller than this and the VLT could not have spotted it, but this would be tiny to considered dangerous as an asteroid this size would simply incinerate in the Earth’s atmosphere.
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