events in the universe, from matter falling into a black hole to nature’s most powerful accelerators.
Because they interact with matter so rarely, neutrinos have the potential to probe even deeper than the highest-energy gamma rays. Already the neutrinos detected from our Sun have shown us the nuclear fires burning at its center, and the neutrinos from Supernova 1987A have revealed the second-by-second progress of a supernova explosion. The potential of neutrinos as new “eyes” on the universe is far from being fully realized. Because very high energy neutrinos are more interacting than low-energy neutrinos (i.e., they have a larger cross section), the chance of observing them in a terrestrial detector is greater. Thus, it is more likely that with “eyes” sensitive to very high energy neutrinos, researchers will see astrophysical sources. Even so, enormous detectors (at least a kilometer on a side) are required. The sources visible to such a detector include supermassive black holes, the mysterious gamma-ray bursters, and the high-energy neutrinos produced by the annihilation of dark-matter particles that are captured by our Sun.
While detecting very high energy cosmic neutrinos requires the largest-volume detectors yet proposed by scientists, a host of additional frontier experiments require laboratory space of a different nature. Double beta decay experiments, solar-neutrino projects, detectors to observe accelerator-produced neutrinos at great distances, experiments to detect the dark matter that holds together our own galaxy, and searches for proton decay all require laboratory space that is well shielded from the cosmic rays that bombard Earth. These projects address complementary sets of questions and require a dedicated environment to research and develop the answers.