TUCSON, ARIZONA--Two cosmologies have collided on telescope-dense Mount Hopkins south of here--and the loser for now appears to be the Smithsonian Institution. Last week the U.S. Forest Service rejected the Smithsonian's request to build a $16.6 million telescope array--what would be the largest array of ground-based gamma ray telescopes in the world--on national forest land near the base of the mountain, citing the proximity of a Native American sweat lodge.
Gamma rays emanate from the most powerful and mysterious phenomena in the universe--quasars, supernovae, and the black hole-powered infernos called blazars. Even though they are blocked by the atmosphere, they can be studied from the ground using a technique that scientists from the Smithsonian's Whipple Observatory pioneered at Mount Hopkins in 1968. Gamma ray photons slamming into the atmosphere create a cascade of charged particles, which emit a faint glow of light, known as Cerenkov radiation, that carries clues about the energy and direction of the original gamma ray photon. Whipple scientists have been observing the Cerenkov glow with a single 10-meter optical reflector. They had hoped to maintain their world leadership with a seven-reflector array of 10-meter optical dishes, called VERITAS, for Very Energetic Radiation Imaging Telescope Array System.
Their preferred site, a secluded parcel not far from the observatory's existing base camp, offered excellent shielding from light pollution from the valley below and already has roads and power service, significantly lowering costs. However, less than 1000 meters away is a small earth-and-log sweat lodge operated by a Tucson-based group of American Indians called To All Our Relations. The Indians, with the support of at least four Arizona tribal governments, say the array would ruin the lodge's sanctity and disrupt the Indians' twice-monthly traditional steam ceremonies and cleansing rites, in violation of the American Indian Religious Freedom Act of 1978. More pointedly, Cayce Boone, the 46-year-old Navajo who founded the lodge and obtained a Forest Service permit for it 9 years ago, declared recently that "gamma ray activity and our spiritual practices are not compatible."
"We're very disappointed," says Trevor Weekes, principal investigator for the Whipple project, "because we've been leading this field and now we're on hold while our rivals move ahead." There is a chance, however, that astronomers may be able to proceed with VERITAS--possibly even at Mount Hopkins. Weekes says he hopes to discuss with the Forest Service the feasibility of two alternative sites near the present Whipple base camp. Although both sites suffer from rougher ground and greater exposure to transient light, they retain most of the cost savings of the original plan.