3 ms·
> At far distances gravity is higher than expected for black holes compared to regular stars. If it doesn't follow the square-cube law in the far field, it vio
by hwillis 5y ago
> At far distances gravity is higher than expected for black holes compared to regular stars.
If it doesn't follow the square-cube law in the far field, it violates conservation of energy and creates a whole bunch of situations that don't make any sense. The farther away from something you are, the heavier it would appear to be. The event horizon of a black hole would shrink as you got closer, because light coming from far away would be pulled more over the longer distance. Neutron stars would appear to be black holes if you were far enough away.
Gauss' law for gravity says the total flux through any enclosing surface is proportional to the enclosed mass. If the gravitational potential decreases at 1/d and the area increases at 1/d^2 the mass must increase. That fact also makes it irrelevant if this is something that only happens for black holes- if you're far enough away, the enclosed mass will make it look like a black hole. That means that this effect would be apparent at measurable scales. Tungsten motes would look like miniscule black holes and asteroids would not emit light once you were far enough away.
The Triangulum galaxy is ~2.7 Mly away and ~2.6 kly wide. At 5 kly the rotation curve is totally unexplainable with conventional mass and gravity. If the strength of gravity falls off with 1/r past that distance, the flux enclosed by a 2.6 Mly sphere would be 1000x higher (d^2 area times 1/d flux density) and the apparent mass would be 1000x higher.
General relativity would have quite a few things to explain if galaxies caused more gravitational lensing the farther away they were despite not having any more stars. The fact that we are seeing significant, unignorable effects at the edges of galaxies means that those effects should be FAR larger at even fractions of the distances between galaxies.
- snarfy 5y agoThanks for the follow-up. I really appreciate it.