I think we are in a black hole already. We just don't know it yet. :D
There is actually a recent theory that says this is the case (in a way): http://scitechdaily.com/universe-may-emerged-black-hole-high... .
The strange fate of a person falling into a black hole
51–60 of 164 posts
Re: The strange fate of a person falling into a black hole
#52This article reeks of phlogiston
Re: The strange fate of a person falling into a black hole
#53Earlier quoted context omitted.
> The moment you fall in, Anne is dead eternally long ago. Nonsense. By this logic, if you cross the event horizon feet-first, your head will have died of old age before it gets inside!
It is not so, as the relative time difference between your feet and head is very small (for large black holes). There is no barrier in place of event horizon, but from the POV of external observer it takes infinite time for you to dive.
> the relative time difference between your feet and head is very small
If there's nothing significant going on between your head and your feet, there's nothing significant between your head and an "external observer" two metres above your head.
Say Anne is falling in behind you, and she either decides to "back out at the last minute" or just keep falling with you. As you fall, time is passing more or less the same for the both of you, so we can just go by your clock: You cross the event horizon at t=0, she makes her decision at t=1, and she either crosses at t=2 or doesn't cross at all.
Now, if Anne "backs out", her clock does diverge sharply from yours as she stops her fall and accelerates away from the event horizon, but this clock divergence happens after you've crossed the event horizon, not as you cross it or before.
Re: The strange fate of a person falling into a black hole
#54So, what if you built a shell around the black hole so that no new radiation whatsoever could reach the black hole, and then dumped enough matter into the black hole to absorb all the Hawking radiation orbiting it, and then jumped in. What would Anne see since you are no longer incinerated (she's inside the shell too)?
Also, the article says that for the laws of quantum physics to be preserved, no information can be lost, which is why one clone['s ash] must remain outside the event horizion. But why doesn't the ash fall in the black hole after the one clone gets incinerated, thereby being permanently lost?
Re: The strange fate of a person falling into a black hole
#55I once saw a susskind lecture about the firewall problem where he explained that to check if someone falling into a black hole was incinerated, you'd have to fire so much energy at them, you'd end up incinerating them. Physics is weird. And, apparently, kinda passive aggressive. BONUS EDIT: here's a Greg Egan short story about transhumans diving into a black hole and trying to do physics on the way down: http://grege…
Thank you for this morning's diversion.
Re: The strange fate of a person falling into a black hole
#56Earlier quoted context omitted.
It is not so, as the relative time difference between your feet and head is very small (for large black holes). There is no barrier in place of event horizon, but from the POV of external observer it takes infinite time for you to dive.
> the relative time difference between your feet and head is very small If there's nothing significant going on between your head and your feet, there's nothing significant between your head and an "external observer" two metres above your head. Say Anne is falling in behind you, and she either decides to "back out at the last minute" or just keep falling with you. As you fall, time is passing more or less the same f…
"there's nothing significant between your head and an "external observer" two metres above your head."
Of course, but when we talk about "external observer" far from the black hole, difference appears.
Re: The strange fate of a person falling into a black hole
#57sounds cool, except before you even got close close to the black hole you would be ripped apart by the tidal forces.
Re: The strange fate of a person falling into a black hole
#58sounds cool, except before you even got close close to the black hole you would be ripped apart by the tidal forces.
http://en.wikipedia.org/wiki/Spaghettification
> The point at which tidal forces destroy an object or kill a person will depend on the black hole's size. For a supermassive black hole, such as those found at a galaxy's center, this point lies within the event horizon, so an astronaut may cross the event horizon without noticing any squashing and pulling, although it remains only a matter of time, as once inside an event horizon, falling towards the center is inevitable. For small black holes whose Schwarzschild radius is much closer to the singularity, the tidal forces would kill even before the astronaut reaches the event horizon.
Re: The strange fate of a person falling into a black hole
#59What would happen if Anne was holding a rope attached to you?
Maybe a better question is what happens when something/someone is straddling the edge of the event horizon?
Re: The strange fate of a person falling into a black hole
#60Somewhat related: there is a short story by Greg Egan, "The Planck Dive", describing a voyage (without return) into a black hole, in a scientifically not too absurd way. You can read it online: http://gregegan.customer.netspace.net.au/PLANCK/Complete/Pla...
Have yet to read this but huh – manually responsive web design!