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The visible-light (left) and infrared (right) views of the Trifid Nebula—a giant star-forming cloud of gas and dust located 5,400 light-years away in the constellation Sagittarius Stars are thought to form inside giant clouds of cold molecular hydrogen — giant molecular clouds roughly 300,000 times the mass of the Sun ( M ☉ ) and 20 ...
The total mass of the interplanetary dust cloud is approximately 3.5 × 10 16 kg, or the mass of an asteroid of radius 15 km (with density of about 2.5 g/cm 3). [7] Straddling the zodiac along the ecliptic, this dust cloud is visible as the zodiacal light in a moonless and naturally dark sky and is best seen sunward during astronomical twilight.
Even the much bigger Galilean moons are surrounded by ejecta dust clouds of a few 1000 km thickness as observed by the Galileo dust detector. [129] Around the Earth Moon the Lunar Dust Experiment (LDEX) on the LADEE mission mapped the dust cloud from 20 to 100 km altitude and found ejecta speeds from 100 m/s to a few km/s; but only a tiny ...
Cosmic dust – also called extraterrestrial dust, space dust, or star dust – is dust that occurs in outer space or has fallen onto Earth. [ 1 ] [ 2 ] Most cosmic dust particles measure between a few molecules and 0.1 mm (100 μm ), such as micrometeoroids (<30 μm) and meteoroids (>30 μm). [ 3 ]
Permutation City asks whether there is a difference between a computer simulation of a person and a "real" person. It focuses on a model of consciousness and reality, the Dust Theory, similar to the Ultimate Ensemble Mathematical Universe hypothesis proposed by Max Tegmark.
Dust accelerator tests show that dust trajectories can be determined to an accuracy of 1% in velocity and 1° in direction. [98] The second element of a Dust Telescope is a Large-area Mass Analyzer: [99] a reflectron type time-of-flight mass analyzer with a sensitive area of up to 0.2 m 2 [100] and a mass resolution R > 150. It consists of a ...
Intergalactic dust can form intergalactic dust clouds, known since the 1960s to exist around some galaxies. [1] By the 1980s, at least four intergalactic dust clouds had been discovered within several megaparsecs of the Milky Way galaxy, [ 1 ] exemplified by the Okroy Cloud .
The Jeans mass is named after the British physicist Sir James Jeans, who considered the process of gravitational collapse within a gaseous cloud. He was able to show that, under appropriate conditions, a cloud, or part of one, would become unstable and begin to collapse when it lacked sufficient gaseous pressure support to balance the force of gravity.