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The Schwarzschild Defence

nature.com

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Re: The Schwarzschild Defence

#11

Post by ericbarrett »

iameli wrote: post #9
defrost wrote: post #4

Sure, it's infinite time, in some framework, until the horizon is reached. But it's finite time (an assertation left as an exercise for the reader) until murder .. when the tidal forces tear the husbands atoms asunder.

I thought this too until the most recent xkcd book taught me that if a black hole is big enough it's actually possible to pass through the event horizon without getting torn apart. It's a question about soup. Good stuff.

The story says the black hole was "wreaking havoc in the Kuiper belt," which implies that it's not very big (else it would be wreaking havoc in the entire solar system). So spaghettification on a human timescale is quite possible!

P.S. I love this discussion

Re: The Schwarzschild Defence

#13

Post by defrost »

iameli wrote: post #9
defrost wrote: post #4

Sure, it's infinite time, in some framework, until the horizon is reached. But it's finite time (an assertation left as an exercise for the reader) until murder .. when the tidal forces tear the husbands atoms asunder.

I thought this too until the most recent xkcd book taught me that if a black hole is big enough it's actually possible to pass through the event horizon without getting torn apart. It's a question about soup. Good stuff.

If you enjoyed xkcd on black holes, you might also enjoy this talk:

Black Holes and the Fundamental Laws of Physics

https://www.youtube.com/watch?v=laKp1XeEF74

Re: The Schwarzschild Defence

#15

Post by CobrastanJorji »

ivlivs wrote: post #5

This is also the premise of the novel Gateway by Fredrik Pohl. https://en.wikipedia.org/wiki/Gateway_(novel)

Hoo boy, the first Gateway book really stuck with me. It really hit me when the protagonist explained their suffering. Even if it's decades later for you, how can you get over something or forgive yourself for it if, for them, it's still happening. “She's thinking I betrayed her, and she's thinking it now!"

Re: The Schwarzschild Defence

#16

Post by pontifier »

iameli wrote: post #9
defrost wrote: post #4

Sure, it's infinite time, in some framework, until the horizon is reached. But it's finite time (an assertation left as an exercise for the reader) until murder .. when the tidal forces tear the husbands atoms asunder.

I thought this too until the most recent xkcd book taught me that if a black hole is big enough it's actually possible to pass through the event horizon without getting torn apart. It's a question about soup. Good stuff.

I saw a very interesting lecture on YouTube about what you'd see as you fall through an event horizon.

Basically you catch up to everything that has ever fallen into the black hole before you.

My guess is that it would look like another big bang.

https://youtu.be/BdYtfYkdGDk?t=4126

Re: The Schwarzschild Defence

#17

Post by cyberax »

pontifier wrote: post #16
iameli wrote: post #9

Earlier quoted context omitted.

I thought this too until the most recent xkcd book taught me that if a black hole is big enough it's actually possible to pass through the event horizon without getting torn apart. It's a question about soup. Good stuff.

I saw a very interesting lecture on YouTube about what you'd see as you fall through an event horizon. Basically you catch up to everything that has ever fallen into the black hole before you. My guess is that it would look like another big bang. https://youtu.be/BdYtfYkdGDk?t=4126

Not quite. A fixed observer far away from a black hole sees that objects falling into the black hole become more and more faint, and move towards horizon ever so slower. In a classical situation with a good enough detector you can see the images of ALL the objects that fell into the black hole.

But this is merely an optical illusion. Objects that fall into the black hole emit only a fixed amount of energy before they hit the event horizon (and then the singularity). It just takes infinitely long time for that energy to escape.

And in general, there's no way for the observer to tell if the falling ship is falling towards the black hole or merely accelerating under its own power.

So as you fall down the black hole, the objects in front of you will start getting less red-shifted and brighter as you begin matching velocities with them.

But nothing special (for you) happens at the event horizon.

The images of objects that fell before you, will just continue to become brighter and brighter. In fact you'd even be able to communicate with somebody who just fell in in front of you.

But you don't have a lot of time before the singularity. So you won't catch up with _everything_ that fell before you, and the amount of energy that you absorb from their fading echoes will not be infinite. It won't even be that large.

What will get you, is the fact that this finite amount of energy will get concentrated into an infinitely thin and infinitely bright band at the singularity.

Re: The Schwarzschild Defence

#18

Post by pontifier »

cyberax wrote: post #17
pontifier wrote: post #16

Earlier quoted context omitted.

I saw a very interesting lecture on YouTube about what you'd see as you fall through an event horizon. Basically you catch up to everything that has ever fallen into the black hole before you. My guess is that it would look like another big bang. https://youtu.be/BdYtfYkdGDk?t=4126

Not quite. A fixed observer far away from a black hole sees that objects falling into the black hole become more and more faint, and move towards horizon ever so slower. In a classical situation with a good enough detector you can see the images of ALL the objects that fell into the black hole. But this is merely an optical illusion. Objects that fall into the black hole emit only a fixed amount of energy before they…

I believe there's a directionality component that happens when you fall into a black hole as well. The directions out of the black hole begin to constrict into a point above you, while directions that end at the singularity become more and more spread out, until every direction leads to the singularity as you cross the event horizon.

Edit: this Forbes article describes this effect. https://www.forbes.com/sites/startswithabang/2018/01/19/what...

Re: The Schwarzschild Defence

#20

Post by skrebbel »

hinkley wrote: post #8

Vernor Vinge’s Peace War has balls of stasis, which you can’t see in to tell if the person trapped is alive or dead. So when they figured out how to calculate the lifetime of the bubble, they started putting the guilty party into a bubble timed so they both popped at the same time, which would quickly be followed by your court date if it turned out to be murder.

This sounds really interesting but I have absolutely no idea what you mean. Is the ball the same as the bubble? Why does someone go into it? Who is the “guilty party”?
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