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Late on September 6, a dramatic fireball was seen flying across the skies of the Mexican States of Nuevo León, Coahuila, and Tamaulipas. Images and videos of the spectacular bolide burning up in the sky were released by the Global Atmospheric Monitoring Agency, part of Mexico's Institute of Geological and Atmospheric Research, as well as locals who saw it that night.
While social media allows people to share these spectacular videos, it has also fostered some confusion over footage, terminology, and a possible impact. A fireball video unrelated to the event has been shared widely in connection to it.
While amazing to look at, this event has been described as a meteorite, which is incorrect. A meteorite is a fragment of a space rock that has touched the ground. If it doesn't hit the ground and burns up in the atmosphere it’s a meteor. Or if it’s very bright, like in this case, a fireball. Meteors and fireballs don't always create meteorites, and sometimes they are not even space rocks, but space junk; pieces of rockets and satellites left by humanity in space.
Another perplexing thing is some inhabitants of Ciudad Victoria, the capital of the state of Tamaulipas, have claimed that meteorites from the fireball set fire to bushes in the area around 11pm, which is significantly later than the official observations.
If this is proven to be true it would be an incredibly rare incident.
Meteorites, counterintuitively, are very cold. These space rocks have spent eons in the cold of space before flying through the atmosphere for a handful of seconds. They are not good heat conductors, and the immense friction only affects the outer surface, which turns to plasma. By the time they get close to the ground, the plasma has dissipated, the meteor is moving at terminal velocity, and everything is pretty chilly.
This means meteorites do not leave smoking craters once they hit. And finding them is not at all easy. Australian meteorite hunters were over the Moon earlier this year to have found two new meteorites in just two weeks.
The September Monterrey fireball may have created some meteorites that will be found, or it may have burnt up completely in the atmosphere. We'll have to wait and see.
