3 ms·
A) …why? What makes this interesting to physicists? I understand this as “if stars weren’t stars but instead rigid spheres, and if they were in an impossibly-im
by bbor 2y ago
A) …why? What makes this interesting to physicists? I understand this as “if stars weren’t stars but instead rigid spheres, and if they were in an impossibly-impervious giant sphere, then weird stuff happens”. And…?
B) “since stars rather rarely collide” still blows my mind. I did some napkin math on Reddit a while back on why there will be very few stellar collisions (really, one star falling into another’s orbit?) when andromeda collides with the Milky Way, and the answer is that space is just mind-bogglingly huge. Even the most dense clusters in our galaxy are akin to ~70 1cm diameter spheres per olympic swimming pool.
If god is real, he is surely a giant.
- LegionMammal978 2y agoFor A), if you have a bunch of tiny atoms bouncing around within a regular-sized sphere, then thermodynamics predicts that the sphere will experience some constant amount of pressure, with tiny fluctuations up and down. This result is interesting, since it just takes the ordinary system and asks, "What if we scale it up so that the atoms (stars) interact gravitationally?" Then, there is no equilibrium pressure experienced by the sphere, since the gravitational potential of the stars keeps increasing.
- trhway 2y ago> Then, there is no equilibrium pressure experienced by the sphere, since the gravitational potential of the stars keeps increasing. And GR fixes that by kind of moving the sphere walls farther away, ie. the space geometry changing by the changing gravitational potential.