How Do You See Inside a Volcano? Try a Storm of Cosmic Particles.
The New York Times
Muography, a technique used to peer inside nuclear reactors and Egyptian pyramids, could help map the innards of the world’s most hazardous volcanoes.
The next time the sun is shining, go outside. There may not be a cloud in the sky, but you will be standing in the middle of a spectral rainstorm.
Cosmic rays, emanating from all sorts of high-energy entities, constantly bombard Earth’s atmosphere. Their collisions with gases make tiny particles named pions, which speedily decay into muons, subatomic blobs more than 200 times heavier than electrons. Trillions of muons are shooting toward the ground at close to the speed of light every single second.
When muons encounter an object, some pass right through while others get stopped in their tracks. That means muons can be used to see inside things that would otherwise be inaccessible, from nuclear reactors to the depths of Egypt’s pyramids.
