The Galactic Center is the rotational center of the Milky Way. The estimates for its location range from 7.6 to 8.7 kiloparsecs (about 25,000 to 28,000 lightyears) from Earth in the direction of the constellations Sagittarius, Ophiuchus, and Scorpius where the Milky Way appears brightest. There is strong evidence consistent with the existence of a supermassive black hole at the Galactic Center of the Milky Way. more... |
The Andromeda Galaxy, also known as Messier 31, M31, or NGC 224, is a spiral galaxy approximately 780 kiloparsecs (2.5 million light-years) from Earth. It is the nearest major galaxy to the Milky Way and was often referred to as the Great Andromeda Nebula in older texts. It received its name from the area of the sky in which it appears, the constellation of Andromeda, which was named after the mythological princess Andromeda. Being approximately 220,000 light years across, Andromeda is the largest galaxy of the Local Group, which also contains the Milky Way, the Triangulum Galaxy, and about 44 other smaller galaxies. Despite earlier findings that suggested that the Milky Way contains more dark matter and could be the largest in the grouping, the 2006 observations by the Spitzer Space Telescope revealed that Andromeda contains one trillion (1012) stars: at least twice the number of stars in the Milky Way, which is estimated to be 200–400 billion. more... |
An aurora, sometimes referred to as a polar light, is a natural light display in the sky, predominantly seen in the high latitude (Arctic and Antarctic) regions.[a] Auroras are produced when the magnetosphere is sufficiently disturbed by the solar wind that the trajectories of charged particles in both solar wind and magnetospheric plasma, mainly in the form of electrons and protons, precipitate them into the upper atmosphere (thermosphere/exosphere), where their energy is lost. The resulting ionization and excitation of atmospheric constituents emits light of varying colour and complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of acceleration imparted to the precipitating particles. more... |
Mount Hood is a potentially active stratovolcano in the Cascade Volcanic Arc of northern Oregon. It was formed by a subduction zone on the Pacific coast and rests in the Pacific Northwest region of the United States. It is located about 50 miles (80 km) east-southeast of Portland, on the border between Clackamas and Hood River counties. In addition to being Oregon's highest mountain, it is one of the loftiest mountains in the nation based on its prominence. more... |
The Three Sisters are a complex volcano of three volcanic peaks of the Cascade Volcanic Arc and the Cascade Range in the U.S. state of Oregon. Each exceeding 10,000 feet (3,000 m) in elevation, they are the third, fourth, and fifth highest peaks in the state of Oregon, and are located in the Three Sisters Wilderness, about 10 miles (16 km) south of the nearest town of Sisters. Diverse species of flora and fauna inhabit the area on and around the mountains, which is subject to frequent snowfall, occasional rain, and extreme temperature differences between seasons. The mountains, particularly South Sister, are popular for climbing and scrambling. more... |
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