Physicist: Terrible, terrible things.
The first thing you’ll be likely to notice as you approach the hole is the tidal forces. Tidal forces are nothing more than the difference in gravitational force between the near and far side of an object, and they aren’t particular to blackholes. For example, the tidal force of the moon on the Earth causes tides (hence the name). For any reasonable sized blackhole (less than thousands of suns), the tidal force between different parts of your body will be greater than your body’s ability to stay intact, so you’ll be pulled apart in the up-down direction. For much more obscure reasons, you’ll also be crushed from the sides. These two effects combined are called “spagettification”. Seriously. Assuming that you somehow survive spagettification, or that you’re falling into an super-massive blackhole (which is ironically much more gentle than a smaller blackhole) then you can look forward to some bizarre time effects.
It’s been established for decades that “time moves slower the lower”. For example, GPS satellites have to deal with an additional 45 microseconds every day due to their altitude (they move through time faster). Also, one way to think about gravity is as a “bending” of the time direction downward. In this way anything that moves forward in time will also naturally move downward. At the event horizon of a blackhole (the outer boundary) time literally points straight down. As a result, escaping from a blackhole is no more difficult than going back in time. Once you’re inside all directions literally point toward the singularity in the center (since no matter what direction you move in will be toward the future).
We don’t experience time moving at different rates or being position dependent, so when we start talking about messed up spacetime it’s useful to look at things from more than one point of view.
From an outsider’s perspective (far from the blackhole): As someone falls in they will move slower and slower through time. They will appear redder, colder, and dimmer. As they approach the event horizon their movement through time will halt, as they fade completely from view. Technically, you’ll never actually see someone fall into a blackhole, you’ll just see them get really close.
From an insider’s perspective (falling into the blackhole): First, torn apart and crushed. Things farther from the blackhole move through time faster, so the rest of the universe will speed up from your point of view. As a result the rest of the universe becomes bluer, hotter, and brighter. The blue shift of the incoming light turns it into gamma rays. So, right before you pass through the event horizon, you’ll get nuked with a universe’s lifetime worth of starlight and microwave background radiation turned into nuking nastiness. The event horizon itself is only special from an outside perspective. If you fall in you should pass right through it. However, what you see in the moment that you pass through the horizon is dependent on things we don’t know yet.
-If the blackhole lasts until the universe ends (assuming that the universe ends), then you’ll see the entire history of the universe whip by (bluely). You’ll then find yourself face to face with the singularity. At that point you go away, according to the math. However, the universe is slippery like a greased up eel fresh from the bar exam. It always finds a way to not have singularities where the math predicts it. So, to be safe, I’ll say “no one knows what happens then”.
-If the blackhole evaporates, then all the matter that (almost) gets to the horizon will be torn apart and reappropriated as Hawking radiation. If you were to survive, then you would find yourself as close to the horizon as (for uncertainty reasons) it is possible to be, and you would ride it in as it shrinks. In a blink you’d suddenly find yourself floating around right next to an amazing explosion, as the last of the blackhole evaporates.
Ok, if I understand it right, it is impossible to get to the event horizon because time ends due to time dilation just before you get there – there is no “then” you fall into the black hole.
Likewise, if I’m watching something fall into the black hole, I never see it get there. None of the light from the object gets to me because of gravity redshifts it more and more. So, from a physics point of view, I can’t observe an object passing the event horizon, which is physically equivalent to saying it didn’t happen (the object never passed the event horizon).
But if this is right, then how can black holes possibly form in the first place? For example, say I’m at the centre of a bunch of gas that I can work out is going to collapse under its own gravity to form a black hole. As the gas gets denser and denser, time dilates and the universe ends before the event horizon forms. Likewise, if I’m watching this happen from outside, I also never see the event horizon form no matter how long I wait – so the black hole never gets created. What gives?
There are probably ways around this – like if black holes already existed at the moment of the big bang and so were “outside” time and didn’t need to be formed because they’ve always been there – but it makes me pretty skeptical they exist. Has anyone actually seen one being made?
No one has observed a black hole being formed, but we have seen black holes themselves.
Unfortunately, I don’t know details about black hole formation. It’s not an easy thing to study!
i am in fact still a freshman in college so bare with me. so what you are saying is once you(x) are going near the blackhole or someone who’s watching things go into the blackhole from afar(y), your perception of time changes simply because T=d/s(don’t understand this formula). so something that is much farther from (x) will be faster(if it was possible for your eyes to interpret)….. and if (y) is looking at (x) near the black hole (x) will be moving in slow motion. The thing that i don’t understand is if T=d/(s) and since there is more gravitational force from the black hole that increases (s) wouldn’t that make (T) bigger therefore (x) being the faster object through time and (y) being slower? i am probably wrong about increased speed if closer to (x) so correct me if I’m wrong.
Could you guys make an update for this topic? There seems to be a new theory about a “firewall” directly behind the event horizont (mentioned in this video: http://www.youtube.com/watch?v=XE5PNbsUERE ), which would make the spagettification process theory obsolete…
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I’m Jus An 8th Grader , But There Are A Few Questions I Would Love To Ask
1.) Will There Ever Be A Time Where A Black Hole Get So Close To Earth To Suck Away Our Sun And Planet ?
2.) Can You Give Me Any Super Advanced Information About Black Holes …Information.You Will Be told In Collage ?
will we turn into spaghetti in the black hole?
Will the world end tomorrow on the date of 12/21/2012? Should I just go out and party hard?
when you fall in black hole you become a god. but still stay in this universe
About an observer falling into a black hole, you say: “Things farther from the blackhole move through time faster, so the rest of the universe will speed up from your point of view. As a result the rest of the universe becomes bluer, hotter, and brighter. The blue shift of the incoming light turns it into gamma rays. So, right before you pass through the event horizon, you’ll get nuked with a universe’s lifetime worth of starlight and microwave background radiation turned into nuking nastiness.”
I think this is not correct. From everything I’ve read, an infalling observer cannot tell from local measurements when she crosses the event horizon, but from what you say they certainly will notice it when they get fried. I think what you say would be true (that you would observe blue shifts and be able to watch the lifetime of the universe) ONLY IF you were using a rocket engine to hover above the event horizon. On the other hand, if you are freely falling into the black hole nothing unusual should happen as you cross the horizon since you are travelling “at the speed of light” as you cross the event horizon and will outrun the infalling light.
there is one thing i have to ask,
what if someone actually survives being made into spaghetti and all that then what will happen to them? LIKE WILL THEY JUST BE FLOATING IN THE BLACK HOLE AND DOING NOTHING??
So it is actually possible to be outside of the Point of no Return and still move forward through time?
You always move forward through time from your own perspective, just not from everyone else’s.
That might not answer your question.
Is it Possible for You to go to just out of the Point Of No Return and travel forward through time?
Sorry I didn’t notice the “newer comments” and no not really because I watched a movie from Stephen Hawking and he said that it is theoretical that if you go just out of reach of a lack hole you could aproach the speed of light but not actually catch up to it and go forward through time.
if we go inside black hole we will be burnt into ashes.
Even if we go inside we can even go inside other universe