The Milky Way is the galaxy that contains our Solar System. Its name "milky" is derived from its appearance as a dim glowing band arching across the night sky whose individual stars cannot be distinguished by the naked eye. The term "Milky Way" is a translation of the Latin via lactea, from the Greek γαλαξίας κύκλος (galaxías kýklos, "milky circle").From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies—now estimated to number as many as 200 billion galaxies in the observable universe more... |
Tenaya Lake is an alpine lake in Yosemite National Park, located between Yosemite Valley and Tuolumne Meadows. The surface of Tenaya Lake has an elevation of 8,150 feet (2,484 m).The lake basin was formed by glacial action, which left a backdrop of light granite rocks, whose beauty was known to the Native Americans. Today, Tenaya Lake is easily accessible by State Route 120 and is a popular lake for water activities. more... |
Airglow (also called nightglow) is a faint emission of light by a planetary atmosphere. In the case of Earth's atmosphere, this optical phenomenon causes the night sky never to be completely dark, even after the effects of starlight and diffused sunlight from the far side are removed. Airglow is caused by various processes in the upper atmosphere, such as the recombination of atoms which were photoionized by the sun during the day, luminescence caused by cosmic rays striking the upper atmosphere, and chemiluminescence caused mainly by oxygen and nitrogen reacting with hydroxyl ions at heights of a few hundred kilometres. It is not noticeable during the daytime because of the scattered light from the sun. Even at the best ground-based observatories, airglow limits the sensitivity of telescopes at visible wavelengths. Partly for this reason, space-based telescopes such as the Hubble Space Telescope can observe much fainter objects than current ground-based telescopes at visible wavelengths. more... |
Polly Dome is a prominent 1,640 feet (500 m) foot granite dome on the northwest side of Tenaya Lake and Tioga Road in Yosemite high country. The dome is over 2 miles long and has forested north and west slopes. Southeast portion of the dome, known as Stately Pleasure Dome consist of glaciated and exfoliated bare granite rock. The summit has unobstructed views east to the Cathedral Range, northwest over the Grand Canyon of the Tuolumne and north over Tuolumne Meadows to the Sierra crest. more... |
Pinus contorta, with the common names lodgepole pine and shore pine, and also known as twisted pine, and contorta pine, is a common tree in western North America. It is common near the ocean shore and in dry montane forests to the subalpine, but is rare in lowland rain forests. Like all pines (member species of the genus Pinus), it is an evergreen conifer. more... |
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