Is it possible to escape from black hole?

[Digix]

how about such way to to get out of black hole:

revised question:

we have system of 2 equal size black holes orbiting each other in such distance that horizons overlap but not much. mass center of this system is in the center.
now relatively small and indestructible object is flying along rotation axis directly into mass center of this binary system.
that object will go below horizons of both black holes but since mass center is empty, it wont hit anything.

so it should get out from below horizon? or is there something that can keep it inside.

old version

imagine that you fall into black hole but with very high speed to that you can stay below its horizon for long enough

and while you are falling into it another similar size black hole passes at very close distance, so that they cancel each others gravity but since singularity does not touch horizon they should not merge and can rotate about each other for quite long time.

so if gravity is canceled we can easily get out isn't it so?

flowing question is if we have 2 equal size black holes rotating about each other and they finally fall beyond each other horizons. so according usual theory they should merge into singularity but where their angular momentum will go? it does not seem possible that they can simply fall to the center of this system.

and if such system can at last temporary exist then again we can easily go through its horizon, because gravity center of that formation is empty, so we cant fall and hit singularity and so we should get out from inside of horizon.

is that possible or there is something that can not allow all that happen?

[Neverfly]

Digix, this is a Yes And No answer. I will cover both.

First answer: No.
What you are referring to is - Is it Possible to slip between the two Black Holes by means of a La Grange Point.
The short answer is - not For You. The point would be entirely too tiny for a massive object to fit in.
You may as well try to escape a prison cell through the eye of a needle. Only the Needle eye will give you MUCH MUCH more room than that Lagrangian point

Second Answer: Yes.
This technique is only for the very very patient of people.
Step 1.) Allow yourself to be pulled into the nearest black hole. Become a part of its essence. Embrace your destiny...
Step 2.) Wait patiently for Hawking radiation to cause the black hole to evaporate. Eventually, all the matter that made up your body will evaporate from the Black Hole as well
The downsides...:
1.) It will probably take more time than the Universe has left to exist. So bring a book.
2.) You will be dead. So make sure the book you bring is "The Book Of The Dead."

[Digix]

Digix, this is a Yes And No answer. I will cover both.

First answer: No.
What you are referring to is - Is it Possible to slip between the two Black Holes by means of a La Grange Point.
The short answer is - not For You. The point would be entirely too tiny for a massive object to fit in.
You may as well try to escape a prison cell through the eye of a needle. Only the Needle eye will give you MUCH MUCH more room than that Lagrangian point
"

i don't understand you, La Grange Point is where gravity is zero, but I don't need it to be zero to escape, I just need to partially cancel it enough to be able to escape using my own energy and if I fall into black hole I obviously have enough kinetic energy to smash moderate planet into pieces .

also such system will have horizon, but singularity is not in the center, so I wont hit it is I fall and that means I should go out form the other side or cycle inside indefinitely unless I hit something.

[Neverfly]

i don't understand you, La Grange Point is where gravity is zero, but I don't need it to be zero to escape, I just need to partially cancel it enough to be able to escape using my own energy and if I fall into black hole I obviously have enough kinetic energy to smash moderate planet into pieces .

also such system will have horizon, but singularity is not in the center, so I wont hit it is I fall and that means I should go out form the other side or cycle inside indefinitely unless I hit something.

No.
You are assuming that there is a Weakened area you can fit in.

The force is canceled to a perception of Zero- but even a proton probably couldn't fit through that. (Someone correct me if I'm inaccurate on that point...)

However, these are Black Holes you are talking about. The warp is extreme. There's no edge large enough for even a part of you to skirt.

ETA: for clarity...

Imagine the point of zero- then imagine you draw a spiral out from that point in which each loop corresponds to the factor by which gravity takes more effect.
By the time you reach the loop where the gravity is Almost to the border where you could escape- that loop is still microscopic in size.

[Digix]

do you say that horizon is some ultra sharp transition from nothing to everything?
I expect that in the edge of horizon gravity is still just moderately higher than few meter away from it.

so i don't see why it cant be canceled.

lets use some simple math.
gravity force is inversely proportional to square of distance from the center, so if I move 10% of distance force will increase 30%. I dont see any reason why that cant be canceled. if we have blackholes that overlap horizons 10% then in the center gravity is zero, and increases in both directions in power of 4 probably.
of course that is fast but still we have quite significant area where gravity is weak eanough.

also assume that while I am just little below horizon of one black hole another one is flying at close distance so I will be recaptured into another one, so in which one I will fall then?

[Neverfly]

lets use some simple math.

I'm afraid you're going to need differential calculus instead.

Let's plug in some numbers...:
Solar Mass: 1.9891(10³⁰)
Factor in that by 10³ for at least an intermediate to small Black Hole.
Remember, you have Two Black Holes.
Now, I'll assume for simplicity that your mass is 100 kilos.
Now- here's a pretty thorough rundown on the very basics of calculating it.
http://www.astro.uu.nl/~strous/AA/en.../lagrange.html

ETA: also- scroll to "Stability"

[Digix]

that is not what I am talking about.

lets say that at that La Grange Point gravity is zero, and it of course increases when we move in all directions from it.
but then the question is how fast it increases. and unless it reaches enough force to split me in 2 pieces I can still escape.

[Neverfly]

that is not what I am talking about.

lets say that at that La Grange Point gravity is zero, and it of course increases when we move in all directions from it.
but then the question is how fast it increases. and unless it reaches enough force to split me in 2 pieces I can still escape.

That is what we both are talking about and I just directed you to resources to use to determine whether or not you can escape.

ETA:I may need to double check that link I gave- I only skimmed it- for the proper course.
Otherwise, I will look for another one.

[Lepton]

that is not what I am talking about.

lets say that at that La Grange Point gravity is zero, and it of course increases when we move in all directions from it.
but then the question is how fast it increases. and unless it reaches enough force to split me in 2 pieces I can still escape.

Do you know what tidal forces are and what they do? Gravity is never "cancelled."

[Digix]

I reread that article few times, but it talk about something different,
it is a complex situation when two different size masses orbit around each other, and in that case that La Grange Point point also moves
but here I use 2 equal masses, so that point stays stable and most of calculations are probably not required.
because system is axially symmetric we can just approximate it to 2 stationary point mases that are kept at some distance.

I suppose that should drastically reduce all complexity, so unless force does not follow usual classic physic square law, I don't see any reason to use some complex calculations

to clarify situation I will ask such question:
if I am standing from horizon at 1% distance, and I fell lets say 1N force then if I move exactly in horizon line, how much force will increase?
and hypothetical situation if I move 1% beyond horizon then how much force will increase again.

classical physic answers are simple: each increase will be about 2%, or if it was 1N then at horizon it will be 2N inside on horizon line and 4N beyond.
is this black hole situation somehow different? is there any reason to think that force will start increasing in some other rate than usual?

[Digix]

Do you know what tidal forces are and what they do?

i expect that black holes are enough size that tidal forces are not too high to tear me. of course if black holes are small or you are very close to their center then it is another story.
however there is still particles that are small and relatively indestructible like electrons. they probably can bear any amount of tidal force
or there would be interesting question what will happen if gravity will tear electron into pieces

Gravity is never "cancelled."

why not? It can, like every other field. of course full canceling will happen in one point only

[Lepton]

i expect that black holes are enough size that tidal forces are not too high to tear me. of course if black holes are small or you are very close to their center then it is another story.however there is still particles that are small and relatively indestructible like electrons. they probably can bear any amount of tidal forceor there would be interesting question what will happen if gravity will tear electron into pieces

The larger a BH the less the tidal forces but if you think you can withstand the tidal forces from any cosmological BH you would be mistaken.

why not? It can, like every other field. of course full canceling will happen in one point only

Gravity is always present and always attractive. A lagrange point is not where gravity is canceled, it is just a point of gravitational equilibrium. Gravity is still in effect.

[Digix]

The larger a BH the less the tidal forces but if you think you can withstand the tidal forces from any cosmological BH you would be mistaken.

I dont nedd to withstand them with my body, it is enough if some electron can do that.

Gravity is always present and always attractive. A lagrange point is not where gravity is canceled, it is just a point of gravitational equilibrium. Gravity is still in effect.

ok, lets say we have few positive charges, probably you want to say that they wont cancel each other?

ok then what about school level physic which says that electric field inside of charged surface is zero?
same is applicable for gravity because gravity is zero inside of massive hollow surface sphere.
I don't think there is reason to say that gravity is present when you just cant detect it in any way.

BTW gravity is not always positive, because even mainstream theory states that dark matter have repulsive gravity.

[Lepton]

I dont nedd to withstand them with my body, it is enough if some electron can do that.

Do you know what degeneracy pressure is? If a BH isn't massive enough to overcome electron degeneracy pressure it would not have become a black hole. A black hole's tidal forces can rip apart an electron as easily as it can rip a human apart. The only difference is one of closeness to the EH.

ok then what about school level physic which says that electric field inside of charged surface is zero?

What about it? The net charge could very well be 0?

same is applicable for gravity

No it isn't.

because gravity is zero inside of massive hollow surface sphere.

Gravity is absent? Do you know the equation that describes gravity between any two objects? If there is mass, there is gravity unless of course you want to rewrite Newton.

I don't think there is reason to say that gravity is present when you just cant detect it in any way.

Ah...argument from personal incredulity...I understand now.

BTW gravity is not always positive, because even mainstream theory states that dark matter have repulsive gravity.

Mainstream? It is a proposed mechanism of dark matter which is not fully understood. If it is not fully understood that means the jury is still out or more eloquently the fat lady has not sung. But you can put the cart before the horse if you want. Anyway,we were discussing ordinary, everyday, plain vanilla baryonic matter.

[Neverfly]

Anyway,we were discussing ordinary, everyday, plain vanilla baryonic matter.

The fat lady and I both prefer chocolate.
Especially... Dark Chocolate baryonic matter.

[Jeff Root]

BTW gravity is not always positive, because even mainstream theory
states that dark matter have repulsive gravity.

You are confusing dark matter with dark energy.

Dark matter has ordinary, attractive gravity. It is seen within galaxies
and within clusters of galaxies. Evidence for its existence has been
increasing for many decades.

Dark energy acts like a repulsive force. It is seen between clusters
of galaxies. It was discovered in 1998, just ten years ago. It was
almost certainly given the name "dark energy" in part because of the
already-existing term "dark matter".

-- Jeff, in Minneapolis

[slang]

Digix, in this thread tommac seems to be asking a very similar question, or your question seems to come up in the replies, perhaps the answers there can help you too?

[mugaliens]

how about such way to to get out of black hole:

imagine that you fall into black hole but with very high speed to that you can stay below its horizon for long enough

and while you are falling into it another similar size black hole passes at very close distance, so that they cancel each others gravity but since singularity does not touch horizon they should not merge and can rotate about each other for quite long time.

You bring up a very good side-question: What would the event horizons of two black holes look like if they were oribiting one another such that their non-proximity event horizons overlapped? Would they merge and become shaped like a dumbell?

Or, as I picture them, would their event horizons shrink back in such a way that immediately between them there is a volume of space between, but outside of their event horizons? How would that the geometry warp given their rotations and frame-dragging?

[astromark]

The understanding of what a Black Hole is would seem to be the problem here.
Escaping a black hole is know longer an option. If you get within its grasp you die. Yes orbiting it at high velocity might well save you from it... but, All that other material orbiting or falling in is going to be a problem for you. You die. Having a second B/H come near for you to escape using it as a escape dent in the gravity well... No, you still die. Think of a B/H as nothing more than such a massive amount of mater in such a small space as to have collapsed the very atomic structure its all made of. You best not ever get near one. They are not user friendly and could be considered as hostill...
And yes. They would orbit very fast and get faster as the distance reduced... eventually becoming a very high rotating much bigger ( stronger ) than before.

[Digix]

The understanding of what a Black Hole is would seem to be the problem here.
Escaping a black hole is know longer an option. If you get within its grasp you die. Yes orbiting it at high velocity might well save you from it... but, All that other material orbiting or falling in is going to be a problem for you. You die. Having a second B/H come near for you to escape using it as a escape dent in the gravity well... No, you still die. Think of a B/H as nothing more than such a massive amount of mater in such a small space as to have collapsed the very atomic structure its all made of. You best not ever get near one. They are not user friendly and could be considered as hostill...

I would not ever try to go inside of black hole, but I am talking about the same concept. it is enough if at least some neutrino or electron can escape.
and that can break common statement that nothing ever can escape black hole even if you fall 0.1mm beyond horizon

And yes. They would orbit very fast and get faster as the distance reduced... eventually becoming a very high rotating much bigger ( stronger ) than before.

if they are orbiting each other, them without somehow loosing momentum it seems impossible for them to join why rotation speed should increase?

[Digix]

Do you know what degeneracy pressure is? If a BH isn't massive enough to overcome electron degeneracy pressure it would not have become a black hole. A black hole's tidal forces can rip apart an electron as easily as it can rip a human apart. The only difference is one of closeness to the EH.

ok then, all i need is to find something indestructible. What about throwing small black hole inside of system of 2 bigger orbiting blackholes.?
I suppose you cant rip "singularities" into pieces?

[Digix]

You are confusing dark matter with dark energy.

Dark matter has ordinary, attractive gravity. It is seen within galaxies
and within clusters of galaxies. Evidence for its existence has been
increasing for many decades.

Dark energy acts like a repulsive force. It is seen between clusters
of galaxies. It was discovered in 1998, just ten years ago. It was
almost certainly given the name "dark energy" in part because of the
already-existing term "dark matter".

-- Jeff, in Minneapolis

anyone cared to at least make some hypothesis what is mechanism of that repulsive force? Since i cant find anything about that.
as I know by definition dark energy do not interact by anything else than gravity, isn't it so?
So how that gravity can create repulsive forces?

[spratleyj]

Do you know what tidal forces are and what they do? Gravity is never "cancelled."

Precisely my view... I think he (mistakenly) thinks of gravity as a "field"... which can be "canceled" out with itself? I've read the previous posts, but I'm still a bit confused as to how he thinks gravity would be "canceled"...

[Neverfly]

Precisely my view... I think he (mistakenly) thinks of gravity as a "field"... which can be "canceled" out with itself? I've read the previous posts, but I'm still a bit confused as to how he thinks gravity would be "canceled"...

Perceived effect?
This one may be just wording.
Although the gravity is not "canceled", I THINK he's referring to how opposing forces can give the effect by negating eachother.

A good analogy would be to put Digix in the Middle of a room.
Then Lepton walks over and grabs his arm and pulls him to the west side of the room. Digix will start heading west.
Then Spratleyj runs in and yells, "NO! He's Mine!" and grabs his other arm and pulls him to the east side of the room. Digix will then head east.
Lepton counters and pulls with greater force to the west, and Spratleyj pulls east and Digix ends up in the middle of the room.
So the motion is canceled.
However, the forces are not and Digix may start feeling a wee bit uncomfortable.

[Digix]

Perceived effect?
This one may be just wording.
Although the gravity is not "canceled", I THINK he's referring to how opposing forces can give the effect by negating eachother.

A good analogy would be to put Digix in the Middle of a room.
Then Lepton walks over and grabs his arm and pulls him to the west side of the room. Digix will start heading west.
Then Spratleyj runs in and yells, "NO! He's Mine!" and grabs his other arm and pulls him to the east side of the room. Digix will then head east.
Lepton counters and pulls with greater force to the west, and Spratleyj pulls east and Digix ends up in the middle of the room.
So the motion is canceled.
However, the forces are not and Digix may start feeling a wee bit uncomfortable.

thats because you are going to grab my hands probably, but if you precisely attach string to every subatomic particle in my body and pull them with the force proportional to mass in opposite, I will not fell anything at all.
that is how gravity works, it affects everything that is made of energy. no mater if you are photon or brick no difference no exceptions, so it is impossible to tell if it exist or not, because you just cant compare.

[Digix]

Precisely my view... I think he (mistakenly) thinks of gravity as a "field"... which can be "canceled" out with itself? I've read the previous posts, but I'm still a bit confused as to how he thinks gravity would be "canceled"...

yes gravity always was field same as electric field just weaker.
also gravity is in the list of fundamental forces so i don't see any reason why it should be not a field but something else.
http://en.wikipedia.org/wiki/Fundamental_interaction
gravity is fundamental force, so like all forces it can be canceled with force of opposite direction.

also according to GR gravity is not only force but also can change object mass.

[Neverfly]

thats because you are going to grab my hands probably, but if you precisely attach string to every subatomic particle in my body and pull them with the force proportional to mass in opposite, I will not fell anything at all.
that is how gravity works, it affects everything that is made of energy. no mater if you are photon or brick no difference no exceptions, so it is impossible to tell if it exist or not, because you just cant compare.

Oh ok.

Then you should have no trouble standing on Jupiter then? (Assuming a solid surface).

[Digix]

Oh ok.

Then you should have no trouble standing on Jupiter then? (Assuming a solid surface).

no if I will stand on Jupiter surface then i will break for sure, but if you somehow place another Jupiter in short distance from my head then i will fell not weight, also if you rotate Jupiter fast enough it also help. since acceleration also affects all mass-energy like gravity.

all we need is compensate force on the whole body, not just in some one point.

[spratleyj]

yes gravity always was field same as electric field just weaker.
also gravity is in the list of fundamental forces so i don't see any reason why it should be not a field but something else.
http://en.wikipedia.org/wiki/Fundamental_interaction
gravity is fundamental force, so like all forces it can be canceled with force of opposite direction.

also according to GR gravity is not only force but also can change object mass.

Yes, in GTR gravity isn't a force, unlike the weak, strong, and Electromagnetism forces, which are...

http://en.wikipedia.org/wiki/Gravitational_field

A gravitational field is merely an anaology... the Newtonian gravitational field was constructed when gravity was still viewed as a "force"... unlike electro-weak there is no "physical enity"...


Lastly, I'm not sure how your thinking the black holes "cancel" out each other - do you have a spefic method in mind?

[Digix]

Yes, in GTR gravity isn't a force, unlike the weak, strong, and Electromagnetism forces, which are...

http://en.wikipedia.org/wiki/Gravitational_field

A gravitational field is merely an anaology... the Newtonian gravitational field was constructed when gravity was still viewed as a "force"... unlike electro-weak there is no "physical enity"...

do not forget that your gravity representation is just one of many possible models. if you like you can think about it as about curved space ant time, but this does not forbids to use another model which thinks about it as force.

Lastly, I'm not sure how your thinking the black holes "cancel" out each other - do you have a spefic method in mind?

I just talk about theoretical a way to fly little below horizon and still get out without falling into blackhole.

i will rephrase original question:
in most other discussions and articles everything ends when you hit singularity in the center, but what if we can remove that singularity from the center so you are free to cross the center.
do you get out from the other side. or you are going to hop inside indefinitely.
(we don't drop human here, we use some indestructible object)

what i was talking before were possible ways to remove that singularity from the black hole center, by modifying its gravity field in such way that center of mass becomes empty space.