TOP 10 EXTREME OBSERVATORIES

5. The Super-K Subterranean Neutrino Observatory

Whoa, there! A subterranean observatory? How is an astronomer supposed to study the stars when he or she is buried nearly a mile under a mountain in the Japanese Alps? Welcome to the world of neutrino astronomy -- and the beautiful and bizarre observatory that scientists nicknamed "the glass cathedral."

The Super-Kamiokande (Super-K) neutrino observatory looks like something from a 1970s space comic -- even a "Moonraker" era James Bond wouldn't kill someone inside this thing. It's essentially a giant cylinder lined with 11,000 glass photomultiplier tubes and filled with 50,000 tons of crystal-clear water. Constructed in an abandoned zinc mine, the observatory resembles an artificial subterranean pond. Maintenance crews even take a small boat out to inspect the tubes.

The Super-K observatory exists because of something known as Cherenkov radiation, which is produced by charged particles and scattered by neutrinos in the water. The particles, zipping around even faster than the speed of light, emit a measurable glow, called Cherenkov radiation. The glass tubes lining the inside of the observatory detect this glow and the resulting information helps astronomers to, among other things, identify supernovae.

Read "How Atom Smashers Work" to learn everything you need to know about making neutrinos in the privacy of your own underground complex.

Image credit: Kamioka Observatory, ICRR (Institute for Cosmic Ray Research), The University of Tokyo.