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/sci/ - Science & Math

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6984453 No.6984453 [Reply] [Original]

Question regarding compression of SpaceTime through gravity.

If you travelled in a spaceship towards a blackhole, would it take you a really long time since there is so much spacetime condensed by gravity?

I was thinking of it sort of like an accordion or a fan(smash bros).

So instead of specification (although this would happen eventually) For those inside the spaceship, could they die of old age before reaching the blackhole due to all the spacetime compressed by gravity they'd need to traverse?

>> No.6984475

>>6984453
Its the other way around. Those watching the ship fly into the black hole would die of old age before they reach it. The people in the ship would just get shredded.

>> No.6984487

>>6984475
No no I know the passage of time experienced for those near a large source of gravity goes faster than those elsewhere.

Like you mention, those of us on earth would be at our regular time which is slower than those travelling fast (i.e being sucked in by a large source of gravity)

What I'm wondering though, is that those in the spaceship, they would feel time pass normally, and would the spacetime near a large source of gravity be compressed so that they still have to traverse it which to us on Earth would see almost instantaneous/ stuck in spaghettification; but for those in the ship, would they spend a lifetime crossing that compressed spacetime to reach the black hole, dying before they ever got there?

>> No.6984494

>>6984453
If you travelled towards a black hole you would accelerate, because the gravitional force grows stronger the closer you get.
You would have to compare the extra time needed due to thecondesed space time with the time saved by accelerating/travelling faster.

>> No.6984499

>>6984487
Its the other way around.
Speed up through time, slow down through space.
Speed up through space, slow down through time.

'Gravity' is akin to acceleration. i.e. speeding up through space. Its the intense gravity of a black hole that causes local time to slow down to an apparent stop.
I think...

>> No.6984509

>>6984494
>>6984499

I didnt word my initial post very well. Just picture this:

Does spacetime get crunched by gravity, and if so does the spaceship still travel accross X billion/(x unit) of space till it eventually reaches the black hole?

>> No.6984522
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6984522

>>6984509
Something akin to this. If it was compressed would the traveller feel like he was travelling down the entirety of compressed spacetime? Or just traverse what remains after the compression?

>> No.6984554

>>6984522
http://en.wikipedia.org/wiki/Equivalence_principle

>> No.6984606

>>6984554
Oh man, that looks like its talking about what Im trying to put into words, but I just cant understand it. I don't have any background in sciences, could you help me out a bit by explaining it to me in layman terms?

>> No.6984627

>>6984606
It basically says that you can't tell the difference between gravitation and acceleration. So to anyone inside the spaceship it would just feel like normal free-fall (neglecting tidal effects). To anyone outside that accelerating frame of reference however, the increasingly warped spacetime makes it appear that the ship is moving slower and slower.

>> No.6984633

Time passes normally for everyone, regardless if they are moving at c-1 or standing still.

>> No.6984638

>>6984633
Meant for
>>6984487

>> No.6984639

>>6984627
ah ok, but as to the spacetime crunch near a black hole, would those in the spaceship spend their lifetime travelling towards it, dying before they reached it? Or am I totally wrong on that part of how gravity works.

>> No.6984662

>>6984639
If you want quantitative answers you're gonna have to learn some relativity.

>> No.6984677

>>6984662
buh :( Isn't it a straight forward answer though? Yes or no?

>> No.6984699

>>6984677
>o anyone inside the spaceship it would just feel like normal free-fall
he already answered your question

>> No.6984705

>>6984699
no that doesnt answer what im asking.

Im not concerned with if it feels like normal free-fall or not. Im asking about spacetime compression.

Would the people in the spaceship die before they ever reached the blackhole or not?

>> No.6984708
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6984708

>>6984677
No, it is not a straight forward question.

>> No.6984711

>>6984708
hehehe fair enough. How bout we focus on the people in the spaceship.

My question (possibly very moronic) does spacetime get crunch by gravity? Does the spaceship travel through spacetime as if it were stretched out entirely meaning they'd die before they ever got to the black hole?

>> No.6984717

>>6984711
>does spacetime get crunch by gravity?
>If ship go vroom am ppl kill?
Please take a moment think before you type.

>> No.6984733

>>6984717
:( Ive been thinking about this for a while...

I forgot the ed part my bad heffe.

>> No.6984760

Welp I emailed the Hayden Planetarium, hopefully they can explain things to me in a manner in which I can understand.

Thx for the responses /sci/ appreciate you trying to help me out.

>> No.6984768

>>6984717

why is people like this on sci , they are their own species they contribute nothing because they are dumb and hide it with comments like this. this is all they post on sci. pls just leave yall

>> No.6984776

>>6984639
>would those in the spaceship spend their lifetime travelling towards it, dying before they reached it?
No, from the point of view of the ship, they pass through as normal. If the black hole is large enough, they won't even notice any great gravitational forces as they go through the event horizon.
From the point of view of an observer a long distance from the horizon, the ship will never make it through - they will see the ship slow down, redshift, and spread out over the event horizon.

>> No.6984784

>>6984776
ah ok thanks. Follow up, has this been proven through experimentation? I recall reading about probes used to test special relativity and what not; or is this just what current understanding tells us happens?

>> No.6984790

>>6984711
>they'd die before they ever got to the black hole?

No. If you fall into a blackhole you perceive time as normal. It's the outside observers that would see you getting slower and slower.

http://hubblesite.org/explore_astronomy/black_holes/encyc_mod3_q15.html

here is a nice simulation.

>> No.6984800

>>6984784
>has this been proven through experimentation?

had relativity been not discovered the GPS would never work. The satellites would get out of synch within minutes and we would have no idea why. Relativity is being experimentaly verified every day.

>> No.6984801

>>6984790
Is it not at all possible that we perceive it to be frozen because in reality its travelling through a perhaps near infinity long compressed spacetime due to the black holes gravity?

>> No.6984802

>>6984784

https://www.youtube.com/watch?v=ky4RgRvVDoA

here is a video that explains it in one and a half minute.

>> No.6984805

>>6984801

if you fall down with the clock in your hand it will keep ticking as it normaly would. Only for the outside observer (pictured here as someone looking at the clock through a telescope) it would slow down and seem to freeze. That's where the name 'relativity' comes from - time is relative

>> No.6984820

guys guys I get relativity as it relates to time. Faster you move relative to people back on earth the slower time is for you.

The twin experiment etc...

What im trying to get at though is that if spacetime is condensed by gravity, when a body gets to that condense part do they travel through this: l l O (b hole)
Or do they experience it as this

l ............ ............ l O (b hole)

And is there a way to test that/have they by shooting a probe at the sun for example?

>> No.6984861

>>6984820


>when a body gets to that condense part do they travel through this:

you see, you don't get relativity at all, because it depends on the frame of reference.

from the point of view of the body

> l l O (b hole)

from the point of view of an external observer

>l ............ ............

and it's been experimentaly verified millions of time over the last 100 years

see: http://en.wikipedia.org/wiki/Tests_of_general_relativity

>> No.6984866

>>6984820

and see this:http://en.wikipedia.org/wiki/Tests_of_special_relativity

for special relativity. this is not just a crazy hypothesis, this is something that has been confirmed with a margin of error smaller than any other theory in the history of science.

>> No.6984882

>>6984861
thats what Im trying to understand, is the frame of reference. How has it been proven that that is what occurs for the point of view of the body?

Oh ok so im kinda thinking something else based on your description.

If you new the amount of gravity emitted by a body, could you calculated the spacetime crunch say 100 000km out, and would that then allow you to calculate the time dilation?

E.G 1 million km crunched to 1/10th the spacetime area relative to an outside observer, meaning the time difference would be 10:1 for us on Earth compared to the spaceship travelling near the body of gravity?

>> No.6984896

>>6984882
http://en.wikipedia.org/wiki/Schwarzschild_metric
Yes you can, be prepared for mathematics though.

>> No.6984924

>>6984882

>How has it been proven that that is what occurs for the point of view of the body?

at this point even pop-sci tv shows have proven this by taking an atomic clock on board of an airplane and comparing the time difference with a stationary clock.

>If you new the amount of gravity emitted by a body, could you calculated the spacetime crunch say 100 000km out, and would that then allow you to calculate the time dilation?

first: your English sucks
second: these are high-school level questions. Seriously, I had to learn these equations:

http://en.wikipedia.org/wiki/Length_contraction
http://en.wikipedia.org/wiki/Mass_in_special_relativity#The_relativistic_energy-momentum_equation

etc.
during physics classes at high school.

>> No.6984936

>>6984882
>>6984924

just to be precise: I meant the calculation of length contraction and time dialtion in special relativity (i.e. due to high speed) . General relativity is more complicated in this regard, as this anon >>6984896 pointed out.

>> No.6984946

maybe you'll find this interesting, OP: https://www.youtube.com/watch?v=3pAnRKD4raY

it explains what will happen as you approach a black hole and go past the event horizon, and what an observer would see

>> No.6984948

>>6984924
first as I previously stated I have no background in science, never took physics in highschool. So excuse me for not knowing proper terminology.
2nd, as I've stated a couple of times I have no problem with grasping the differences in time based on relatives speeds. Before you answer questions in threads it might be a good idea to read it so you don't just repeat what other people have already stated.
Lastly why waste your time linking wikis that are heavy on math to someone who's already stated they have 0 background in science. C'est la meme chause que parlait en Francais.

>> No.6984974

>>6984946
interesting video, but still doesn't explain why or why not what I'm thinking is right or not.

Ill just have to sit tight and hope to get a response for my email, or meet an astrophysicist in person.

>> No.6984988

>>6984948
>linking wikis that are heavy on math

topkek.

the length contraction equation features squaring, a root, multiplication and substraction. All of these things are something a 12 year old is expected to comprehend in any educational system of any developed country in the world.

>> No.6985043

>>6984948

so.. you have no problem grasping special relativity (speed related), but general relativtiy (gravity related) is troublesome?

>> No.6985094

>>6984801
You could say that. The spacetime is compressed to the point of a singularity, so yes, that would explain the time dilation for the observer point of view. Not for the traveller - he just falls down as usual. Beyond the event horizon no information can get out, so the observer will never see the traveller "fall through". Observer will just see the traveller as he approaches infinitesimally slowly towards the event horizon.

>> No.6985116

>>6984974
The answer to what I think you're asking is this:
From the point of view of the observer, in his frame of reference, the traveller's trajectory is "deformed" so much that it seems infinite at the event horizon.
From the point of view of the traveller, in his respective frame of reference, the trajectory is still as long as it was before, so let's say the 2km to "cross" the event horizon is still the same 2km. That is because the whole spacetime is warped, including the traveller himself, by the same factor locally.

>> No.6985125

>>6985116

yeah, that would work, except OP has been given that answer a million times and he still doesn't get it.

>> No.6985665

>>6984453
Time is dilated around a black hole. From the perspective of an outside observer, you would appear to flatten out, turn darker and redder, and slow down until you seem to take a very long but finite amount of time to cross the even horizon. From your perspective, it all happens very, very fast.

>> No.6985691

>>6984487
No, geodesics on the Schwarzschild spacetime (also Reissner-Nordstrom, not sure about Kerr-Newman family atm) are incomplete, i.e. you will hit the singularity in finite proper time. See Wald or Straumann or any other good graduate text.

>> No.6985700

>>6984487
>>6985691
Your question is essentially a problem in Wald (1984). Problem 6.6 asks you to calculate the maximum proper time you could survive within the Schwarzschild radius before hitting the singularity. The formula you're looking for is http://www.texpaste.com/n/nx93hies.. (No fucking clue how to LATEX on /sci/.) Don't ask me how to derive that, I have absolutely no idea.

>> No.6985796

>>6984453
You should watch "Interstellar", then read "The Science of Interstellar". It's a great popsci introduction to black holes and wormholes and relativistic physics in general.

>> No.6985806

Would it be possible to stay in orbit right next to the event horizon, condensing time so much that you'd live until the black hole itself died?

>> No.6985864

>>6985806

no. timescales aside (it takes approximately a fucktillion years for a black hole to evaporate via HR) you getting closer or further from the event horizon does exactly jack shit to the length of your life relative to the black hole.

>> No.6985867

>>6985796

the relativistic effects are exaggerated a lot in the film due to the artistic licence. No way there could exist a planet so close to the black hole that spending several hours there equals decades on earth.

>> No.6985902

>>6985806
As mentioned in the other reply, Hawking radiation takes a fucktillion years to evaporate a black hole. I want to say that a solar mass black hole takes 10^70 years to evaporate. (Might be off by a few orders of magnitude, but you get the idea.)

>> No.6985960

>>6985864
>fucktillion
Is that a metric fucktillion or an American fucktillion?

>> No.6985966

>>6984453
>>6984487
it depends on what theory of physics you are using
for the most part the effects between theories stays the same
while the underlying cause within the theory is what changes.

Per the theory of relativity
time slows down and space-time becomes denser
dependant upon the size of, and proximity to the nearest gravity well
or dependant upon how fast you are moving or accelerating in relation to the speed of light.
the faster you move or the closer your proximity to a gravity well
the slower local time moves when compared to an observer
who is at rest and outside the influence of a significant gravity well.

the speed of light simplified is the speed of one planck meter per planck second
anything that would attempt to pass this speed limit
would experience it's composite matter ripped apart and scattered on the quantum scale
or would experience the shearing of the 5th dimensional fabric of space-time
in what is commonly referred to as a worm-hole, which would manifest
as either a 2nd dimensional hole, or as a 3rd dimensional portal.

nearing the speed of light would produce a Doppler effect on the local space time
that would manifest as gravitational and temporal distortions
that would propagate in much the same way as a wake behind a boat
or a sonic cone behind a jet. perhaps even creating the equivalent of a sonic boom
basically a spacial-temporal photonic boom, the effects of which
would be gravitational and temporal distortions crashing against the local space-time
as if waves upon a beach.

>> No.6985989

>>6984453
>>6984487
>>6985966
as for experiencing the gravity well of a black hole
while time to the explorer would appear to pass as normal
time would actually be slowing down exponentially
in relation to the distance between the starship and the blackhole's event-horizon.
an outside observer would see the starship just hanging in orbit around the black hole for years
before being sucked into the accretion disk and torn apart by the gravitation forces
all of which would appear to take between seconds, minutes, to mere hours to the crew.
depending how close they are to the front of the gravitational Doppler wake.

at the edge of the event-horizon time literally stands still as a direct effect
of the gravitational field of the black hole. as such any incoming matter from the accretion disk
is pushed from the equator towards the poles, where the downward force of the gravitational field,
combined with the pressure from the incoming matter from the accretion disk, basically creates
an open air fusion reactor at each pole, and with nowhere for the energy to go but out
the result is two jets of hawking radiation jetting from the poles into space.

>> No.6986531

did the thread die?