/big-black-holes/ The tech blog of Neil Ennis Mon, 14 Mar 2016 06:19:15 +0000 hourly 1 /big-black-holes/comment-page-1/#comment-196 Tue, 11 Oct 2011 22:31:15 +0000 /?p=366#comment-196 Thanks for the reply, Nick. You’re right. My approach is too simplistic because I don’t understand it as well as I should. Was I correct in thinking that the force of gravitational attraction just outside the event horizon could be close to 1g if the black hole was large enough? If so, does this make any difference? I.e. could a hypothetical observer safely approach the event horizon without having to deal with the normal issues we read about such as tidal forces, time dialation, increased mass, extremely curved space, etc?

]]> /big-black-holes/comment-page-1/#comment-195 Tue, 11 Oct 2011 16:04:09 +0000 /?p=366#comment-195 The simple answer to everything here is that your approach is too simplistic. It is often useful to talk about black holes in terms of escape velocity, but ultimately wrong, because it leads to the question, “What if I accelerate?”. The answer is that when you do the full GR, you find that the causal structure of space-time forbids exiting the event horizon, regardless of your trajectory. Inside the horizon, the direction of “time” switches with the direction of “space”, meaning that all future-directed trajectories lead further inside the black hole.

]]>