Dark Matter Heats a Star Near a Black Hole ✛ ✎ ✦
Astronomers Fritz Zwicky and Vera Rubin found: the Universe is full of dark matter — invisible substance that betrays itself only through gravity. Around supermassive black holes it clumps. One of them, Sagittarius A* at our galaxy’s center, was studied by Stephen Hawking. Nearby orbits the star S4714. It speeds along an elongated orbit, and at closest approach accelerates to 24,000 km/s — thousands of times faster than any human-made craft.
At such speed, the star rubs against dark matter particles. Each collision transfers energy, like friction between palms generates heat. The black hole’s gravity holds the star, and its plasma is pierced by invisible particles. Computer models showed: if dark matter particles are light, frictional heating rivals the output of the nuclear furnace. The star gains a hidden battery.
Paradox: leaving the dense cloud, the luminary could dim, as if the battery ran out. This reshapes stellar evolution and explains odd behaviors in some stars. It also affects cosmic rays and the evolution of entire galaxies.
S4714 accelerates to 8% of light speed — thousands of times faster than any human-built spacecraft.
In fiction, there are 'dark stars' powered by dark matter annihilation (Oliver Langmead’s novel 'Dark Star'). The idea of frictional heating, though, hasn’t yet appeared in plots.