Ursa Minor (cave) Ursa Minor (cave) Ursa Minor Cave is part of Sequoia National Park, a naturally formed system of caves in California's Sierra Nevada. The cave was discovered in August 2006 by four cave explorers from the Cave Research Foundation who found a softball-sized hole on a cliff face in the mountains. After widening the hole to allow for human entry, the explorers discovered one of the most spectacular caves in the western United States. The cave has since been named "Ursa Minor," because of the large bear skeleton found in the cave. The cave was featured in the September 2007 issue
Ursa Minor and dimming at a rate of 0.02 magnitude a year. Its distance has been calculated as 5,000±800 parsecs (16,300 light-years), which puts its location in the galactic halo. Taken from the villain in "The Magnificent Seven", Calvera is the nickname given to an X-ray source known as 1RXS J141256.0+792204 in the "ROSAT All-Sky Survey Bright Source Catalog" (RASS/BSC). It has been identified as an isolated neutron star, one of the closest of its kind to Earth. Ursa Minor has two enigmatic white dwarfs. H1504+65 is a faint (magnitude 15.9) star that with the hottest surface temperature—200,000 K—yet discovered for a