Why Are Black Holes Considered Bottomless Pits in Space-Time?

AI Thread Summary
Black holes are often described as bottomless pits in space-time due to the singularity at their core, which is theorized to possess infinite density. The escape velocity of a black hole exceeds the speed of light, preventing anything from escaping its gravitational pull. However, some argue that a black hole does not need to have infinite density if it is large enough in volume, suggesting that density could be finite. The discussion highlights the complexity of defining density in the context of black holes, particularly regarding the singularity. Ultimately, the nature of black holes and their singularities remains a topic of ongoing debate in astrophysics.
photon
Messages
125
Reaction score
0
Why is it said that a black hole is a literally bottemless pit in space-time? If it weren't bottemless, then the singularity inside would not have to be of infinite density.

I'm not sure if I have missed anything important, so PLEASE help!
 
Physics news on Phys.org
Yes, but a black hole is, by definition, of infinite density.\\


Well, the way you are putting it, that's true. In general, a black hole only has to be massive enough that light cannot escape it. (It's "escape velocity" is greater than the speed of light.)

A large (in volume) black hole would not have to have infinite density and would not be "a literally bottemless pit in space-time".
 
What do you mean by "density" ?
Huh ?
mass/volume ?
mass=finite
volume<>0...(the radius of the horizon is not 0...)
so density is not infinite...or am I wrong ?
 
I think he was talking about the singularity's density.
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Thread 'Struggle to understand the concept of the question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Similar threads

B Black hole equivalence
Replies
20
Views
2K
I Does Kerr's argument against singularities apply to all black holes?
Replies
12
Views
2K
I You can't actually enter a blackhole?
Replies
40
Views
3K
I What is the Connection Between Black Holes and the Big Bang?
Replies
2
Views
2K
B Question about the Entropy of a Black Hole Singularity
Replies
17
Views
3K
I Black Hole Diameter: Is It Finite or Infinite?
Replies
36
Views
6K
I Kerr disputes singularities in Kerr Black Holes
Replies
7
Views
3K
I Do any real macroscopic black holes have a singularity?
Replies
11
Views
2K
B I Need Help on Understanding Some Basic Astrophysics / Sand Clock Universe
Replies
5
Views
2K
I If electrons can be pointlike particles, why can't black holes?
Replies
16
Views
1K

Hot Threads

Recent Insights

Back
Top