Submitted via IRC for Bytram
Novel experiment validates widely speculated mechanism behind the formation of stars
The theory holds that MRI[*] allows accretion disks, clouds of dust, gas, and plasma that swirl around growing stars and planets as well as black holes, to collapse into them. According to the theory, this collapse happens because turbulent swirling plasma, technically known as "Keplerian flows," gradually grows unstable within a disk. The instability causes angular momentum -- the process that keeps orbiting planets from being drawn into the sun -- to decrease in inner sections of the disk, which then fall into celestial bodies.
Unlike orbiting planets, the matter in dense and crowded accretion disks may experience forces such as friction that cause the disks to lose angular momentum and be drawn into the objects they swirl around. However, such forces cannot fully explain how quickly matter must fall into larger objects for planets and stars to form on a reasonable timescale.
[*] MRI: Magnetorotational instability.
(Score: 2) by aristarchus on Friday February 08 2019, @10:57PM (2 children)
The spin is the thing. What determines the axis of the accretion disk? What determines the direction of the angular momentum? Keplerian flows are very nice, once these parameters are in place, so it suggests a solution to one problem in stellar formation, one of many. Very interesting. I just love the smell of science in the morning!
(Score: 0) by Anonymous Coward on Saturday February 09 2019, @03:17PM (1 child)
Dark master determines the axis and direction.
(Score: 2) by aristarchus on Saturday February 09 2019, @09:35PM
There is this: The Spatial Orientation of Planetary Nebulae Within the Milky Way [arxiv.org] Kind of the other end of the star life, but still.