February 27, 2014
Every year, countless objects pass through our solar system. Most of them do only that, pass through. Others, however, leave a more lasting impression. Thankfully, our home planet Earth is protected by its atmosphere, which prevents many of these outer space missiles from doing any damage by incinerating them during entry. Other worlds, such as our own orbiting moon, are not so fortunate. The moon’s surface is marred by many pockets that are evidence to the many impacts it has suffered throughout the history of our solar system. Still, such impacts are quite rare and the odds of actually seeing one are close to none.
That is, unless you just so happened to be looking up at the moon sometime on September 11, 2013, when the moon seemed to gain a strange glowing spot for about eight seconds. That was when a meteor of about 400kg and a width of somewhere between 0.6 and 1.4 meters (about the size of a small car) collided with the moon, producing an explosion equivalent to 15 tons of TNT, three times greater than the previous documented impact which happened that March, and was the largest impact on the moon seen to date. The impact happened at the Mare Nubium, an ancient lava-filled basin that has a much darker coloration than much of its surroundings. The object was disintegrated upon impact, but the thermal glow of the superheated crater was visible from Earth, as long as you just so happened to be looking up at just the right time. Normally, these flashes last for only a fraction of a second. However this one was much greater than most, longer and more intense than anything that has ever been observed before. Fortunately, the blast was seen by Professor Jose Maria Madiedo, who was operating two telescopes in southern Spain when the event happened. In his words, “At that moment I realised that I had seen a very rare and extraordinary event.”
Those Spanish telescopes are used as a part of the Moon Impacts Detection and Analysis System, or “MIDAS,” which monitors the moon’s surface for exactly these sorts of events. In addition to Professor Madiedo of the University of Huelva (UHU), this project is also being undertaken by Dr. Jose L. Ortiz from the Institute of Astrophysics of Andalusia (IAA-CSIC). The purpose of this, and similar, programs is to observe lunar impacts in order to give insight to astronomers and other researchers regarding the potential risks should such a thing happen to Earth (again). While most objects, the September 11th event, are too small to cause any damage thanks to our protective atmosphere, but there are much larger bodies out there that could cause us problems should they veer too close.
While I am in no personal hurry to go the way of the dinosaurs, events like the one that took place on September 11, 2013 are fascinating to read about. It is incredible to think that every year there might be many times more impacts both on the moon and against our own atmosphere than any of us are ever aware of. While hopefully the larger ones steer clear of us for some time to come, the smaller ones certainly provide us with the welcome awe-inspiring sight to behold.
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