geografia: Uranus

Evidence: 100 • authority: 72

Uranus is the seventh planet from the Sun. It is a gaseous cyan-coloured ice giant. Most of the planet is made of water, ammonia, and methane in a supercritical phase of matter, which astronomers call "ice" or "volatiles". The planet's atmosphere has a complex layered cloud structure, and has the lowest minimum temperature (49 K (−224 °C; −371 °F)) of all of the Solar System's planets. It has a marked axial tilt of 82.23°, with a retrograde rotation period of 17 hours and 14 minutes. This means that in an 84-Earth-year orbital period around the Sun, its poles get around 42 years of continuous sunlight, followed by 42 years of continuous darkness. Uranus has the third-largest diameter and fo…

Evidence: 64 • authority: 72

The rings of Neptune consist primarily of five principal rings. They were first discovered (as "arcs") by simultaneous observations of a stellar occultation on 22 July 1984 by Patrice Bouchet, Reinhold Häfner and Jean Manfroid at the La Silla Observatory (ESO) who were conducting a star occultation observation program proposed by André Brahic, Bruno Sicardy and Françoise Roques of the Paris-Meudon Observatory and William B. Hubbard's teams at Cerro Tololo Interamerican Observatory in Chile. They were eventually imaged in 1989 by the Voyager 2 spacecraft. At their densest, they are comparable to the less dense portions of Saturn's main rings such as the C ring and the Cassini Division, but m…

Evidence: 45 • authority: 72

Umbriel () is the third-largest moon of Uranus. It was discovered on October 24, 1851, by William Lassell at the same time as neighboring moon Ariel. It was named after a character in Alexander Pope's 1712 poem The Rape of the Lock. Umbriel consists mainly of ice with a substantial fraction of rock, and may be differentiated into a rocky core and an icy mantle. The surface is the darkest among Uranian moons and appears to have been shaped primarily by impacts; however, the presence of canyons suggests early internal processes. The moon may have undergone an early endogenically driven resurfacing event that obliterated its older surface. Covered by numerous impact craters reaching 210 km (13…

Evidence: 45 • authority: 88

Occultation observations reveal ring system around Uranus. Much precise calculating and thorough planning went into preparations earlier this year for the first observed occultation of a star by the planet Uranus, but it was chance—and cautious allowance for chance—that led to the serendipitous discovery of five or more rings about the planet. Large uncertainties in the time at which the occultation would commence and in estimates of how far north it would be visible caused several observers to turn on their photometric equipment well in advance of the predicted moment—and only thus did they detect the unforeseen dips in the occulted star's light intensity that revealed Uranus as the second…

Evidence: 36 • authority: 72

Haumea (minor-planet number 136108) is a dwarf planet located beyond Neptune's orbit. It was discovered in 2004 by a team headed by Mike Brown of Caltech at the Palomar Observatory, and formally announced in 2005 by a team headed by José Luis Ortiz Moreno at the Sierra Nevada Observatory in Spain, who had discovered it that year in precovery images taken by the team in 2003. From that announcement, it received the provisional designation 2003 EL61. On 17 September 2008, it was named after Haumea, the Hawaiian goddess of childbirth and fertility, under the expectation by the International Astronomical Union (IAU) that it would prove to be a dwarf planet. Nominal estimates make it the third-l…

Evidence: 31 • authority: 80

Control of Growth and Metabolite Production in Persicaria Tinctoria Using Extremely Dark Light

Evidence: 27 • authority: 80

The discovery of the Uranus ring system

Evidence: 27 • authority: 80

Present knowledge of the Uranus ring system

Evidence: 27 • authority: 72

The Solar System is the gravitationally bound system of the Sun and the masses that orbit it, most prominently its eight planets, of which Earth is one. The Solar System is an isolated single-star planetary system (not part of a larger star system) within the Milky Way Galaxy. The system formed about 4.6 billion years ago when a dense region of a molecular cloud collapsed, creating the Sun and a protoplanetary disc from which the orbiting bodies assembled. The Sun accounts for 99.86% of the Solar System's total mass. Inside the Sun's core, hydrogen is fused into helium, releasing energy that is emitted through the Sun's photosphere. This creates the heliosphere and a decreasing temperature…