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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.
Sir James Hopwood Jeans OM FRS [1] (11 September 1877 – 16 September 1946 [2]) was an English physicist, mathematician and an astronomer. He served as a secretary of the Royal Society from 1919 to 1929, and was the president of the Royal Astronomical Society from 1925 to 1927, and won its Gold Medal .
PPTS may refer to: Palestine Pilgrims' Text Society, a Victorian academic society; Pulsed plasma thrusters, a type of spacecraft propulsion; Prospective Piloted Transport System, a Russian spacecraft; Pyridinium p-toluenesulfonate, a chemical reagent; Point perfect transcription services
The Jeans equations are a set of partial differential equations that describe the motion of a collection of stars in a gravitational field. The Jeans equations relate the second-order velocity moments to the density and potential of a stellar system for systems without collision.
A pulsed plasma thruster (PPT), also known as a Pulsed Plasma Rocket (PPR), or as a plasma jet engine (PJE), is a form of electric spacecraft propulsion. [1] PPTs are generally considered the simplest form of electric spacecraft propulsion and were the first form of electric propulsion to be flown in space, having flown on two Soviet probes ...
Firehose instability (a.k.a. hose instability), not to be confused with the similarly named Firehose instability in galactic dynamics; Fish instability, Free electron maser instability, Gyrotron instability, Helical (Helix) instability, Jeans instability, [23] [24] Magnetic buoyancy instability. Interchange instability (a.k.a. flute instability ...
The world has entered an era of increasing instability as countries around the globe boost military spending in response to Russia’s invasion of Ukraine, the Hamas attack on Israel and China’s ...
After the instability has run its course, the system is typically "hotter" (the motions are more random) or rounder than before. Instabilities in stellar systems include: Bar instability of rapidly rotating disks; Jeans instability; Firehose instability [4] Gravothermal instability [5] Radial-orbit instability