Folks: happy asteroid day! Officially ruled out is a dangerous space rock that had been ranking high on lists of potential hazards. We may all now heave a sigh of relief because it was once predicted that Earth would be attacked in 2052. The Mount Lemmon Observatory in Arizona made the first discovery of the 50-meter-wide asteroid 2021 QM1 in August 2021. All is well thus far. According to the European Space Agency, about a dozen near-Earth objects can be seen each night with a clear sky and a decent observatory (ESA). However, routine follow-ups were less promising. According to ESA’s Richard Moissl, head of planetary defense, “these early observations gave us more information about the asteroid’s path, which we then projected into the future.”
We could predict its movements around the Sun in the future, and in 2052 it may approach Earth in a hazardous manner. The risk increased as the asteroid was watched more closely. The asteroid’s course took it near to the Sun as seen from Earth, which meant that the brilliance of our star outshone everything in its area and made it impossible to continue watching the space rock just as the information was beginning to seem a bit worrying.
Marco Micheli of the ESA’s Near-Earth Object Coordination Center said, “We only had to wait.” To top it all off, 2021 QM1 was traveling away from Earth in its present orbit, so by the time it emerged from the Sun’s glare, it may have been too dim to be seen. Fortunately, the Very Large Telescope (VLT) of the European Southern Observatory was ready to go into action as soon as the asteroid became visible once more, albeit it was still difficult to find.
The Milky Way was directly behind it as it passed across a section of the sky, which only made problems worse. Thousands of stars would need to provide the background for seeing our tiny, dim, retreating asteroid, according to Olivier Hainaut of the ESO. These observations of asteroids would prove to be among the toughest that we have ever done.
It turned out to be the smallest asteroid ever seen, in fact. QM1 was 250 million times fainter than the weakest stars currently detectable to the human eye, with a magnitude of 27 on the brightness scale used by astronomers. The scale’s numbers go smaller the brighter the item is. For comparison, the Sun’s brightness is -27 and Betelgeuse, the 10th brightest star in the sky, is 0.42. A 2052 collision was ruled out and the dangerous asteroid was taken off the high-risk list as a result of images taken of it on May 24.
