(Oct 28, 2019 03:24 AM)Leigha Wrote: . . . Is it safe to assume that a star is always ''struggling'' against the force of gravity? (to not be destroyed?)
Yah, the crushing effects of gravity ironically generate enough heat to trigger fusion of hydrogen into helium, producing enough energy to counteract it. Depending upon a star's mass, they eventually lose the battle with different results. After its red giant phase, Sol's less violently ejected or lost outer envelope will become an expanding planetary nebula hanging around for a few millennia. The leftover core will become a white dwarf star that endures for a vastly longer time than the original sun.
Significantly more massive stars than Sol will explode into supernovae after they reach the point of having to fuse neon into iron (not enough energy produced by that process to counteract gravity). Again depending upon the mass, what's remains will be either a neutron star or a black hole with very powerful attractive forces. A neutron star has an upper limit to how much more matter it can absorb from its surroundings before collapsing into a black hole. The latter, however, can increase indefinitely as long as the amount and rate of what it devours outruns its own tedious evaporation via Hawking radiation.
Oct 28, 2019 03:24 AM
(This post was last modified: Oct 28, 2019 04:19 AM by Leigha.)
