Linked Questions

0
votes
1answer
52 views

It's about black holes [duplicate]

If is was to stand deep inside the center of a black hole and was to point a light gun straight up at the center of the event horizon, would the beam of light make it out of the black hole?
60
votes
10answers
6k views

Do all black holes have a singularity?

If a large star goes supernova, but not enough mass collapses to form a black hole, it often forms a neutron star. My understanding is that this is the densest object that can exist because of the ...
14
votes
2answers
30k views

What is the escape velocity of a Black Hole?

The escape velocity of Earth is $v=\sqrt{\frac {2GM}{R}}$, where $M$ is the mass of the Earth and $R$ it's radius (approximating it as a sphere), and is much less than light speed $c$. But I want to ...
6
votes
3answers
4k views

Time dilation as an observer in special relativity

I've been having a discussion regarding time dilation relating to special relativity and how it should be observed from the FoR (Frame of Reference) of "the person moving" : I assert- If we have a ...
5
votes
2answers
2k views

Kinetic energy of a photon and Schwarzschild radius

I have read here, that $\frac{1}{2}mv^2$ must not be applied on a photon ever. If i want to calculate escape velocity $v_e$ i need to use $\frac{1}{2}mv^2$ because we say that kinetic energy (...
2
votes
2answers
716 views

Dipping a Dyson Ring below the event horizon [duplicate]

The basic assumption about inescapability beyond the Event Horizon is that the necessary escape speed (orbital speed) would exceed speed of light, therefore no object can achieve it. Now, would it be ...
4
votes
2answers
509 views

Frame dragging around a black hole

If you have one stationary non-rotating black hole, being orbited by a 2 or more black holes just outside each other's event horizons does this alter the size of the central black hole's event horizon?...
2
votes
2answers
255 views

Is this derivation for schwarzschild radius for a black hole of mass $M$ correct?

Consider a body of mass $M$. We know that light can’t escape a black hole. Speed of light being the highest possible could be set as the escape velocity.(??) Then $$\text{Escape velocity}^2=(2GM/r)$$ ...
0
votes
1answer
204 views

Crossing the Schwarzschild radius

I am struggling to understand where the problem (i.e. impossibility of getting out) at the Schwarzschild radius comes from, solving the equation of motion for a massive particle on a radial geodesic $...
0
votes
1answer
76 views

If you make an effort to escape a black hole, would your free fall velocity be slowing down?

If you make an effort to escape a black hole, would your free fall velocity be slowing down? It is known that you can't escape once you passed event horizon. But is it possible to slow down? Or should ...