The theory that up to 90% of the universe appears to be "missing" is something that continues to puzzle and fascinate scientists around the world. A big portion of that missing puzzle could be dark matter, which may or may not exist.
Now it appears scientists are prepared to take the search to unlock the secrets of dark matter to new extremes, with plans underway to undertake dark matter experiments up to 8,000 feet beneath the Earth's surface in a huge underground network of tunnels.
The complex, which currently exists at the 5,000 foot-level as the Sanford Underground Laboratory, is being described as the world's deepest underground laboratory, and takes advantage of 370 miles of tunnels at the site of a former gold mine in South Dakota
While the Cheyenne Mountain Complex is well-known for being buried within the granite of Cheyenne Mountain, other deep-underground facilities exist for science purposes around the world, including a particle physics laboratory located under the Gran Sasso mountain in Italy. The underground location protects experiments from interference from radiation.
Key to the Sanford Lab research will be the Large Underground Xenon Detector (LUX), which contains liquid xenon, which researchers hope will be affected by, and show signs of, coming into contact with dark matter.
While much attention is going to the Sanford Lab experiment, previous attempts to detect dark matter interactions have reportedly failed to provide evidence, including the use of a LUX detector installed at the Gran Sasso site in Italy.
While the Sanford Lab has officially had its dedication ceremony at the 43850 foot level, there is a proposal to go deeper. The new 8,000 foot deep complex would be named the Homestake Deep Underground Science and Engineering Lab (DUSEL) and would takeover from the current Sanford Lab.
Interestingly, the site played a historic role as the location for a neutrino detector built by Ray David in 1965, which is considered a turning point in modern astrophysics.
An interesting illustration and photos picturing the Sanford Lab Large Underground Xenon Detector can be seen here.