ARCHEOLOGY AND PHYSICS
Cosmic Messages from Ancient Pyramids
By Davide Castelvecchi
What can subatomic particles from outer space tell us about the Pyramid of the Sun and the enigmatic people of Teotihuacán who built it? Hint: the particles don’t carry any messages from the aliens.
In February, a Mexican team led by a physicist and an archeologist announced that they were deploying a particle detector — the kind of contraption that carries out experiments at atom smashers — in the guts of the pyramid, where it is now sitting for a year and collecting data. In the end, the team hopes the data will reveal hidden tunnels and rooms that could shed light on the Tehotihuacan civilization.
The detector is taking a scan of the huge building the way your dentist takes X-rays of your teeth. The amazing thing is that scientists just need to place the detector — the equivalent of a photographic plate with a very, very long exposure time — and the galaxy will provide the equivalent of the X-rays.
That’s because Earth’s atmosphere is constantly hit by particles coming from space, or cosmic rays. Descending nearly at the speed of light, these particles disintegrate as they smash with air molecules, and the debris rains down on the ground as a constant, invisible, largely harmless rain. Many of these particles are able to penetrate through walls, although thicker walls will stop more of them. Some will be even able to reach down deep inside the pyramid. The detector collects data from the particles that cross it; seeing more particles from a given direction could point out to the presence of gaps in the pyramid’s bulk — and perhaps to hidden rooms that survived 1,000 years of looting.
As it turns out, the idea of using cosmic rays to scan a pyramid is not new, although it was to me. It was thought up in the 1960s by Luis Alvarez, the physics Nobel prize winner mostly known for having proposed the asteroid-impact theory of the extinction of the dinosaurs. Alvarez tried it at the Khafra pyramid in Egypt, but he couldn’t find any hidden passages.
Surely Alvarez was not going to outsmart the aliens who built the pyramids and hid their secrets in them?