According to Professor Peter Schultz, the object that crashed into a dry riverbed in Peru (reported last year on TFOT as “space-disease-in-Peru“), was indeed a meteorite. It left a 49-foot-wide crater and soil ejected from the point of impact was found at a distance of several hundred meters away (equal to nearly four football fields). Evidence gathered from the soil showed “planar deformation features”, or fractured lines in sand grains found in the ground, indicating that the meteorite maintained a high speed as it shot through the atmosphere. Scientists think the object was traveling at a speed of roughly 15,000 miles per hour at the moment of impact.
“Normally with a small object like this, the atmosphere slows it down, and it becomes the equivalent of a bowling ball dropping into the ground,” Schultz said. “It would make a hole in the ground, like a pit, but not a crater. But this meteorite kept on going at a speed about 40 to 50 times faster than it should have been going.”
Despite what was expected, scientists have determined the fireball was a stony meteorite. For a long time stony meteorites of this type were considered to be relatively fragile, and were expected to explode as they entered the Earth’s atmosphere, so that by the time they reached the ground, little evidence of their existence remains. The stony meteorite that crashed in Peru last September was mostly intact before impact, although typically, fragments shoot off in all directions as the object speeds closer to Earth. Schultz thinks the because of the meteorite’s high speed and velocity when approaching the atmosphere, fragments could not escape past the “shock wave” barrier. Instead of breaking off the meteorite, Schultz believes the fragments “reconstituted themselves into another shape”, probably more aerodynamic, so that the meteorite encountered less friction as it sped towards Earth.
Schultz’s theory could upend the conventional wisdom that all small, stony meteorites disintegrate before striking Earth. His research may have implications for our research of Mars, where craters have been discovered in recent space missions. “They could have come from anything,” he said. “It would be interesting to study these small craters and see what produced them. Perhaps they also will defy our understanding.”
More on Schultz’s research can be found on Brown University’s website.