i have a question on this — perhaps someone here can answer it. if the centre of each galaxy has a super black hole and ‘we’ are all slowly circling it — is it inevitable, over a huge span of time that every galaxy will disappear into the centre. i realise the distances are vast and the timeline is huge, but does this mean every spiral galaxy (isnt that them all?) are slowly under the gravitational influence of the centre..and therefore (for want of a better word) falling into the black hole at the centre? does this mean all planetary matter in the universe will eventually disappear leading to a cold dark (absolute zero i would guess) universe...never been able to get anyone to give an answer on that...so any help appreciated
Yes, and nebulae and dwarf stars will be hit hardest!
(Actually I don’t know. I’m curious too.)
I’m not entirely sure but I don’t see any reason that stars can’t orbit the center like planets around the sun, meaning they won’t necessarily get sucked in.
The reason I’m not sure is because, in spite of the high gravity, the distance from us makes the force on us very low, so I don’t know if we do actually orbit it.
On the other hand, you have dinky objects at the extemes of the solar system that are orbiting the sun so it seems at least possible that we do actually orbit the center of the galaxy.
Good question. Keplerian orbits (like the earth around the sun) are stable, according to Newtonian mechanics, gravity will not cause the earth to spiral into the sun. In general relativity an orbiting pair radiate gravity waves, which remove orbital energy and cause them to spiral inward, eventually. The fate of universe appears to be a long slow thermodynamic cool down, with every particle approaching absolute zero, gathered up in gravitationally-bound galaxy-cluster-sized lumps. I’ll miss the old universe.
But there’s a lot we don’t know, so no one really knows for certain.
Its the “Black Hole Era” which precedes the Dark Era. The only structured matter left in the universe are black holes and the time span we are talking about here is trillions of years. The universe is not going to fall back into itself in a big crunch, its just going to get very, very, very cold and fade away.
Eventually black holes dissipate due to Hawkings Radiation.
Actually the earth feels no effect of the central black holes gravity of the milky way. The spiral arms of the milky way are the product of gravitational waves created at the early creation of the galaxy but now are maintained by the combined gravitational fields of all the stars in the galaxy. Our star is not falling towards the gravitational center of the galaxy, but is being carried along on the gravity waves of the galaxy itself.