# What would happen if someone was sucked into a black hole?

phinds
Gold Member
2019 Award
I have just read From Eternity to Here by Sean Carroll and he makes the same claim: using rocket engines would cause you to hit the singularity sooner.

Not understanding the physics of black holes I wonder if this is something to do with the shape of the gravity well causing all paths to lead "down" or if he is talking about what is seen from an observers POV?
I don't see how he could be talking about any observer other than the guys inside (one firing his rockets, one not) since no observer outside the EH is relevant.

I seem to recall hearing this before but I don't understand it.

Let's hope someone who DOES understand it joins the conversation and explains it.

I think it is that your light cone is bent to point at the singularity, so there's no direction you can move in that results in you heading away. I too would like this confirmed or refuted.

phinds
Gold Member
2019 Award
I think it is that your light cone is bent to point at the singularity, so there's no direction you can move in that results in you heading away. I too would like this confirmed or refuted.
Oh, I think that's definite, but it does not answer the question of why firing rockets gets you there sooner than not firing.

using rocket engines would cause you to hit the singularity sooner.
I guess this idea comes from the fact that free fall maximizes proper time. But it doesn't apply here! Free fall from A to B (points in spacetime) is the longest path between A and B, but if you fire your rockets you will land in C (elsewhere on the singularity).

This paper is interesting: http://arxiv.org/PS_cache/arxiv/pdf/0705/0705.1029v1.pdf

I think it is that your light cone is bent to point at the singularity, so there's no direction you can move in that results in you heading away. I too would like this confirmed or refuted.
We'll never answer these questions untill we send in a probe with a high-def camera and a scooper to retrieve core samples.

Yes, even light can't get out once you fall in; so we'll just lower half the probe through the event horizon then pull the data back up through ultrasonic waves on the tether.

phinds
Gold Member
2019 Award
I guess this idea comes from the fact that free fall maximizes proper time. But it doesn't apply here! Free fall from A to B (points in spacetime) is the longest path between A and B, but if you fire your rockets you will land in C (elsewhere on the singularity).

This paper is interesting: http://arxiv.org/PS_cache/arxiv/pdf/0705/0705.1029v1.pdf
Thanks for the reference. It completely contradicts the statement that we've been discussing and to me sounds MUCH more reasonable than that statement.

phinds
Gold Member
2019 Award
We'll never answer these questions untill we send in a probe with a high-def camera and a scooper to retrieve core samples.

Yes, even light can't get out once you fall in; so we'll just lower half the probe through the event horizon then pull the data back up through ultrasonic waves on the tether.
I can't tell whether your statement was tongue in cheek or unwitting nonsense. Care to comment?

Thanks for the reference. It completely contradicts the statement that we've been discussing and to me sounds MUCH more reasonable than that statement.
well, it doesn't completely contradict it. If you start from rest at the event horizon, freefall still gives the longest possible time, and any acceleration will make it worse.

Some physicists have theorized that black holes are actually gateways to strange other dimensions, is there any evidence of that?

phinds
Gold Member
2019 Award
Some physicists have theorized that black holes are actually gateways to strange other dimensions, is there any evidence of that?
So, I take it the article itself, which I did not read, must contradict the summary paragraph, which I did read, which says pointedly:

In general, the use of such rockets can increase your remaining time, but only up to a maximum value; this is at odds with the “more you struggle, the less time you have” statement that is sometimes discussed in relation to black holes.

Simon Bridge
Homework Helper
Some physicists have theorized that black holes are actually gateways to strange other dimensions, is there any evidence of that?
That would be a "no, there is no evidence that some physicists have theorized that Black Holes are actually gateways to strange other dimensions." Whatever that is supposed to mean.

This question is actually answered more completely in many of the references already provided to you. If you are not going to read the replies, why should anyone bother replying?