Well, I was wrong. The mysterious crater formed in Peru last month was the result of a meteorite impact. Peruvian scientists have produced an initial report (in English) and have recovered some fragments of the meteorite. Locals took much of the material, but enough material was recovered to determine that the meteorite was a stony meteorite consisting of mostly pyroxene, olivine, feldspar, and other minerals. Further analysis including isotopic ratios and further mineralogy will be done.

A New Scientist article reports that despite finally having a respectable and clear report completed, several aspects of the impact are still mysterious. Stony meteorites of that size usually break up high in the atmosphere so this may a fragment of a larger body. Most meteorites are cold when they hit the ground (the exterior gets hot during the short period of maximum heating but the inside of the meteor maintains the coldness of space). However, the groundwater in the crater steamed and boiled for some time after the impact. One scientist postulates that hot, compressed air trapped in a shock wave on the front of the meteor caused the water to warm up and the air was bubbling up through the thick mud. It is my understanding that most meteorites that hit the ground are slowed by the atmosphere to a free fall speed of no more than a few hundred miles per hour. Perhaps this object had a higher than normal initial speed and was not slowed down much by the atmosphere. This would explain the crater and perhaps the “boiling water.” High kinetic energy impacts can cause unusual and strange effects. Most of the kinetic energy is released as heat which could have caused the effects seen.

Also, the sickness of the locals was over reported. Only 30 cases of nausea and headaches were reported. One scientist reported that it could have been the psychological shock of a big explosion in a very quiet part of the world. To me and others, that is a likely explanation.

Finally, it is reported that the crater will likely only last a few months due to the softness of the soil, the high water table, and the impending rainy season. It would have been nice for the locals to have a tourist attraction for such an interesting and unusual event.

Still, the whole story is utterly fascninating. It’s pretty cool that a rather ordinary rock the size of a basketball can cause such a ruckus. The effects of something bigger hitting are scary. Meteor Crater in Arizona was caused by a 50 meter diameter meteorite and was the equivalent of a large thermonuclear weapon (2.5 megatons of TNT equivalent). And remember, the natural enemy of the hole is the pile!