I 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.<p>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: <a href="http://gregegan.customer.netspace.net.au/PLANCK/Complete/Planck.html" rel="nofollow">http://gregegan.customer.netspace.net.au/PLANCK/Complete/Pla...</a><p>also here's his page explaining the physics in the story: <a href="http://gregegan.customer.netspace.net.au/PLANCK/Planck.html#CONTENTS" rel="nofollow">http://gregegan.customer.netspace.net.au/PLANCK/Planck.html#...</a>
I don't think this article is representative of current serious thought about black holes. I'm a bit out of date on this stuff, and I was never any sort of expert, but let's see:<p>1. This reality splitting thing sounds wrong. I've never heard of it. Ignoring quantum effects, if you fall into a black hole and survive crossing the horizon, Anne will see you get closer and closer to the horizon, but she won't see you get there. She won't see you burnt up and she certainly won't collect your ashes. The only fundamental difference between what you see and what Anne sees is that by the time she gets bored of watching, you will only have perceived a tiny amount of time passing.<p>2. Free fall doesn't protect you from burnination. If the horizon is surrounded by enough fire and brimstone and you free fall through it, you're still going to burn to a crisp.<p>3. If I remember my old problem set correctly, a black hole big enough for you to live your life in would be truly huge. IIRC the supermassive black hole at the center of the Milky Way would give you about 0.1 ms before you hit the singularity.
So I've had a question about stellar mass black holes that I can't seem to be able to get answered (the question was deleted for /r/askscience).<p>How does a stellar mass black hole actually form a singularity given the fact that there's gravitational time dilation? Wouldn't the heart of a black hole slow down relative to an outside observer as mass is added to it so that you never actually reach infinite density? It seems like you're fighting the upwards curve of a parabola to make that happen, and meanwhile you're releasing pressure from above via hawking radiation.
>there is no paradox, because no one person ever sees your clone. Anne only sees one copy of you. You only see one copy of you. You and Anne can never compare notes.<p>Can't you? Why can't Anne "gather up your ashes" and send them into the black hole, where you can inspect them? Shouldn't that go against the "no cloning theorem"?
I really don't understand this sentence:<p>> <i>So Anne takes her bit, A, and puts it through her handy entanglement-decoding machine, which spits out an answer: either B or C.</i><p>(Note: I have a Ph.D. in Math and half a major in Physics that include a few quantum mechanics curses (for example, with the Sakurai book))<p>What is a entanglement-decoding machine? You cant use entanglement to send information. Just repeat after me: You cant use entanglement to send information. This is one of the most common misunderstandings about entanglement.<p>When you make the measurement and get the collapse, you only get a random value (with a weighted probability). It's not possible to use that to get information about B or C.
Somewhat 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:<p><a href="http://gregegan.customer.netspace.net.au/PLANCK/Complete/Planck.html" rel="nofollow">http://gregegan.customer.netspace.net.au/PLANCK/Complete/Pla...</a>
"That's the thing about black holes. They're not just annoying obstacles for space travellers. They're also theoretical laboratories that take the subtlest quirks in the laws of physics, then amplify them to such proportions that they can't be ignored."<p>I also use this strategy to think about philosophy and science. People often think that because they are extremes, they are not relevant. However, they are as relevant! And they force us to think outside our natural instinct.
This was very confusing, and a prime example of the horrors of popularisation.<p>Watch this talk about the firewall paradox instead, more technical but at least it makes sense!<p><a href="https://www.youtube.com/watch?v=tEtt4A7WsDg" rel="nofollow">https://www.youtube.com/watch?v=tEtt4A7WsDg</a>
"In a big enough black hole, you could live out the rest of your life pretty normally"<p>Free falling in your ship and suit waiting for you to be crushed to death... pretty normally
I always assumed the differing 'views' of what would happen crossing into a black hole was a product of the interplay of the equivalence principle and 'relativity of simultaneity' that Special/General relativity already accounts for.<p>I had thought that upon reaching the event horizon the outside observer sees time 'stand still' because no light from your continued motion the other side of the event horizon can reach them, effectively freezing the observers view. Or thought of another way, the curvature of spacetime at the event horizon reaches the equivalent velocity of c due to the extreme warping of spacetime, so light can't escape and 'time' stops for the observers view of the freefaller because light can't get to them, the freefallers then image freezes and slowly fades.<p>Special relativity says the relativity of simultaneity is pronounced at high % of c, would it not be pronounced in an extreme gravitation field? A gravitational field is equivalent to acceleration so...<p>If the curvature of spacetime at the event horizon has an equivalent velocity inwards of c, thereby preventing light escaping, would this not lead the outside observer to see one thing and the freefallers to experience another which special relativity's relativity of simultaneity explains?<p>I say this becaue the light cone escaping the black hole must experience high gravitational fields (i.e equivalence principle) and the free faller continues on their geodesic experienceing 'no' force (save for tidal forces which in the case of a large black hole won't spegetify them just yet).<p>So the _outside_ observer is seeing the effect of the freefaller and the freefallers observable light cone experiencing the equivalence principle which necessarily would cause relativity of simultaneity to become more pronounced. At the event horizon, with an equivalent spacetime curtavure of velocity c, surely this would mean that the outside observer would see no more regardless of what the freefaller observs and all that would be accounted for by relativity of simultaneity.<p>I guess I thought of it as applying relativity of simultaneity to a gravitational field (by way of the equivalence principle) and not just velocity as the train thought experiment did.<p>Is this line of reasoning incorrect - I'm assuming it is - why?
What do we know about the nature of entanglement? Does it make sense to talk about entanglement between regions inside and outside of an event horizon? Couldn't it be the case that entanglement too breaks down somehow at the event horizon?
It's hard to say exactly why as I'm not a scientist, but I find the credibility of this piece extremely suspect. It seems to be making a number of sensational claims (splitting of reality?) and I don't get the feeling that the author understands this material on anything other than a completely amateur level. Also, this seems to commit the famous mistake of thinking that you will be ripped to shreds by tidal forces the second you cross the event horizon. This is well-known to be false. For sufficiently large black holes you can peacefully pass beyond the horizon (unless there's something else going on, like a firewall).
Interesting read, but I must say I was a bit disappointed by the ending. Resolving the paradoxon relies on the computational complexity of finding out with which other particle it is entangled with? Somehow that doesn't feel right.
Thought it was weird in Interstellar that Cooper survived getting pulled into the black hole. Interesting that surviving is one of the 2 possibilities.
So, 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)?<p>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?
There are minimal tidal forces for very large black hole. You would not be torn apart approaching or crossing the event horizon then. You would be unable to leave or signal out of the hole.
I guess I've always misunderstood blackholes. I was under the impression that they were simply a vacuum created as a by product of the every expanding "space". Sure they are sucking things up and growing, but space is always expanding.
Didn't Patrick Hayden write a paper about this stating it was essentially an unphysical situation in the lifetime of the universe? I seem to remember this from the fundamental physics prize lectures....
What would happen if Anne was holding a rope attached to you?<p>Maybe a better question is what happens when something/someone is straddling the edge of the event horizon?
Most of theoretical science and science fiction is complete bullshit. They use some analogy and run with their wild imagination to create anything utterly non nonsensical. The space time fabric etc is just an analogy to avoid people from the real mathematical equations of relatively and what people did with it created whole shit load of theoretical science around that analogy.
And if you ever start to think Doctor Who is a wishy-washy-weeny, someone once pissed him off and he did this to them. Moral of the story: don't fuck with time lords.
You can only get inside black hole after time ends.
That's because universe-time stops at the horizon.<p>The moment you fall in, Anne is dead eternally long ago.<p>Also, you are incinerated by a billion years of starlight per your second, including energetic particles I guess.<p>You will observe the end of universe and death of everything in it before diving.
How can something that doesn't really exist such as space and time possibly be warped? Physicists need to get a grip and understand that their model of the universe is completely wrong. There is no space or time and the universe has no shape.
Talk about the moral decay of theoretical physics...<p>This is just like one of those miller lite ads where somebody smacks a beer bottle on the table and on the TV they see a mix of dog racing and bikini mud wrestling.<p>The trouble is that it is so hard to get established that the field is dominated by old fogies; as a kid in the 80s I was aware of this contradiction but it was censored from the physics literature. Instead the greybeards were worried about the information paradox which turned out to be no paradox at all.
I recently saw the movie Interstellar starring Matthew McConaughey. It answers the question of what happens if you fall into a blackhole and it involves a bookcase, I don't want to spoil it for those who haven't seen it.<p><i></i>Edit: Seems the people downvoting me are a bit sensitive and don't have a sense of humour. Sorry to anyone who was somehow offended.<i></i>