Which time slows down?

[control]

if an observer was looking at a particle going into a black hole, and he saw the particle slow down, then time from the particle's view would speed up to infinity and the black hole would be long gone. The particle wouldn't have anything happen to it as it would never get to the middle of the black hole until the black hole no longer existed.

 

When it is said "the faster/closer to a black hole you go, time slows down", this means the closer someone went, the more real time they would skip and they would therefore appear younger if they went too close. If they went right into the middle, or if someone went to the speed of light, they would skip infinity...

[□h=-16πT]

As an inertial frame O approaches the event horizon, time runs as usual. However from an external reference frame the time it takes for O to reach the horizon is infinite.

[control]

The light emitted by the object getting sucked in would never escape the event horizon and enter anyone's eyes. If time is constant, an outside observer would see the object falling into the black hole get fainter and slower at the same time, and at the event horizon the object would appear to disappear, yet for the object it would just fall into the black hole and get crushed and there would be no time distortion. This is what I think would really happen, and seems like what you think would happen too.

 

If time stops at the speed of light, then if you were a photon, the universe would take zero time to pass by. That must be why photons don't change, because it would be like trying to change something by moving at infinite speed in a world of constant time (which relativity says the universe is not).

[amrit]

Control: if an observer was looking at a particle going into a black hole, and he saw the particle slow down, then time from the particle's view would speed up to infinity and the black hole would be long gone. The particle wouldn't have anything happen to it as it would never get to the middle of the black hole until the black hole no longer existed.

 

When it is said "the faster/closer to a black hole you go, time slows down", this means the closer someone went, the more real time they would skip and they would therefore appear younger if they went too close. If they went right into the middle, or if someone went to the speed of light, they would skip infinity...

 

Amrit:

Whatever physical motion is time.

The speed of time depends on the density of space.

In a fast airplane the density of space is higher, so clocks run slower. This lower time speed do not depends on the reference frame, it is not real only for the observer on the earth, it is real also for the observer on the plane. Let’s say I’m on the Earth, you are on the plane. Before you take off we control clocks. When you come back we control clocks again and we see that my clock was faster, your clock has some dilate, the speed of your clock in the plane was slower.

see more: http://forum.physorg.com/index.php?showtopic=4321

[control]

Nothing is infinite. This is a multiversal rule with no exceptions.

(you may start saying void is infinite, but void = nothing so the rule is still true)

 

Density of space would mean something is in the way even if you are outside the shockwave of light from the first bit of the big bang. However, that is the limit of the universe's space capacity (which is expanding at the speed of light) and outside it there is no dust and gas to slow you down and so no speed limit. The speed of light is only special inside because if any matter collided with other matter at the speed of light it would get crushed to a singularity (but would have no effect as its gravitational field strength would not change).

[amrit]

About density of space

 

1. Loop quantum gravity introduces the idea of granular structure of cosmic space; space is made out of quanta of space QS. One can consider that "granular space" has some density that depends on the amount of matter into it. More matter in a given volume of space, higher its density. Density of space is a physical property of the space that determinates its geometric shape, its roundness.

Density of space D is in relation with mass according to the formula

 

D = m x G

 

where D is density in the centre of the object, m is a mass of the object and G is gravitational constant. Introducing this formula in math formalism of SR and GR can be seen that density D is a concrete physical quantity that determinates gravity and motion.

 

2. Cosmic space is build up out of quanta of space QS that have a size of Planck. Gravitational force acts between quanta of space QS. Every QS attract the QS around it. Between QS near by the moon and QS near by the earth gravitation acts on the distance and instantly via QS that are between them. Gravitational force does not propagate into space, gravitational force is the force that builds up the space. The wall is made out of bricks. The cement keeps together the bricks. Gravitational force is a cement that keeps together the QS, the bricks of the space.

 

The strength of gravitational force depends on the density of QS that build up cosmic space. Density D of QS of a given volume of cosmic space depends on the density of matter contained in it:

 

formula 1: D = m x G

 

where D is the density of QS in the centre of the material object, m is the mass of the object and G is the gravitational constant. QS are “elastic”. Its density changes with the amount of matter. The gravitational force Fg between two material objects is given by the following relation:

 

Fg = (D1 x D2) / ( r on square x G)

 

where r is the distance between the centers of the two material objects.

 

Gravitational force Fg on material body or on a particle that has a mass m depends on the density G of space.

 

Fg = (m x D) / r on square

 

where m is a mass of a body or particle, D is the density if space in a centre of planet or star, r is the distance from the centre of the planet or star; r can be shorter or longer as t the radius of the planet or star.

 

In a centre of the planet or star Fg on a material object or mass particle is:

 

Fg = (m x D) m10^-2

 

Gravitational acceleration g in a given distance r from the centre of the planet or star is:

 

g = (m x G) / r on square

 

m is a mass of planet or star,

G is gravitational constant

r is a distance from a centre

 

 

According to the formula 1: D = m x G

 

g = D / r on square

 

where D is the density of space in the centre of planet or star and r is a distance from the centre

 

3. Relation between mass m of particle and density of space D into it is:

D = m x G

where G is gravitational constant. The density of space inside of the same atom is higher on the earth than on the moon, because on the earth the density of space is higher than on the moon. The same atom will have a bigger weight on the earth than on the moon. But its density D that defines its mass will remain the same. So by moving through the space the weight of particles changes, but its mass remains the same. Photon is an exception here. Around the photon there is no additional density D of cosmic space, so photon has no weight and no mass.

 

Energy of matter and energy of space inside of a material object or mass particle are in equilibrium, equal: Espace ( Es ) = Ematter ( Em )

 

Es = Em = m x cc, ( D = m x G)

 

where m is a mass of the object, c is speed of light, D is density of space around the object and G is gravitational constant.

 

Es = Em = (D x cc) / G

 

Energy of space Es inside of particle or material object depends on the density of space D.

 

First experiments that proves mass increasing of particles that moves fast were done about 100 years ago. The faster the elementary particle, the bigger will be its mass. We call that “The Relativistic Mass Increase”.

 

The formula E = 0.5m x vv shows the relationship between the increase in mass of the relativistic particle and its increase in kinetic energy.

 

In this formula we can change m with D/G and we will get the formula:

 

E = (0.5D x vv) / G

 

which shows clearly that the kinetic energy of particle depends on the density D of space into it and on the speed v

 

The mass of accelerated particle is increasing because the with the speed increasing the density around the particle is increasing.

 

Density of space is increasing also inside of the inertial system that moves with the higher speed regarding the inertial system that moves with the lower speed. This higher density of space causes the speed of clocks is slower into the faster inertial system.

 

Higher density of cosmic space inside of an fast inertial system is the bridge SR and GR. In SR the speed of inertial system causes the increasing of the density of cosmic space, in GR the mass causes the increasing of the density of cosmic space. “Inertial mass” and “gravitational mass” of a material object or particle are equal because the density of cosmic space in inertial mass and gravitational mass is equal.

 

Let’s say we are in a fast space ship that travels far away from the stars and planets in cosmic space with low density. With increasing of the speed of the space ship the density of cosmic space into it will increase. By attaining a certain speed the density of the space in the space ship will be equal to the density on the surface of the earth. Space ship travel than with this constant speed. We have two material bodies that are identical. Both of bodies will behave in exact the same way in the space ship and on the surface of the earth. The density D of space in both bodies is equal. This means the equality between inertial mass and gravitational mass.

 

4. Cosmic space is composed by quanta of space (QS) having the size of Planck length. Light is a physical event in which photons are "jumping" from one quantum of space to another in a Planck time. Cosmic space is a medium of light, inertial systems move through the cosmic space. That's why the speed of light is “maximum speed” in the universe and it is same in all inertial systems.

 

Light has a double particle-wave nature simultaneously. A single photon jumping from one quantum of space to another in its trajectory is the central part - particle. The “chain jumping” of the photon changes the frequency of the QS on its trajectory from its basic frequency to the frequency of the photon. The central part of the photon also changes the vibration of QS around its trajectory that is its circumference part - wave.

 

In a “double slit experiment” we can settle instruments and observe photon's particle-part or we can settle instruments differently and observe the wave's part of the photon.

When we settle instruments to observe a particle, we will observe (detect) the particle part of the photon, when we settle instruments to observe a wave, we will observe (detect) the wave part of the photon. Scientist (Observer) should not play any role in this experiment.

 

5. When a star has a mass of 3,2 masses of sun in its centre the density of cosmic space is so strong that gravitation overpowers all other forces. Matter transforms back into quanta of space (QS) that build up cosmic space.

 

Beyond Schwarzschild Radius gravity is so strong that prevails above all other forces. All elementary particles transform back into the energy of cosmic space. Matter and space are made out of the same “stuff”. Black holes are the “fabric” where matter transforms back into space. In big explosions of AGN space transforms back into matter.

Universe is composed by one energy. The basic packets of this one energy are QS. Energy is circulating continuously “space-matter-space-matter-…”. Universe is a self-renewing system. There was no beginning and there will be no end.

 

Schwarzschild Radius Rs is:

 

Rs = (2G x m) / (c x c)

 

G is gravitational constant

m is mass of the stellar object

 

According to the formula (1) D = G x m

D is the density of cosmic space in the centre of the black hole

 

Rs = 2D / (c x c)

 

Inside Rs gravitation has no direction, density of space does not increases towards the centre of the black hole. The area inside of Rs is a fabric where matter transforms back into the QS of cosmic space.

 

A mass has a weight when it is in a space where density changes, it has a direction. At the “weightless” Lagrange point between earth and sun happens that density D of space is stable, there is no change of density, no direction. So gravity is there because gravity is carried by the quanta of space QS, and QS build up cosmic space also at the “weightless point”. If it would be no gravitation at the “weightless point” earth would fly away long time ago.

A body at Lagrange point will not move, but this does not mean that gravitational force is not there.

 

Decreasing of the duration of motion of the orbital period of the binary pulsar PRS1913+16 is the result of matter transforming back into space in the centre of one star. This diminishes the mass of the star, diminishing of the mass causes diminishing of the speed of rotation, with diminishing of the speed the duration of motion on the orbit is increasing.

There is no gravitational radiation, gravitational waves do not exist.

[Norman Albers]

In a radial sense time stops at an event horizon. In an angular sense, it stops at the center of my electron field! There is dielectric singularity to where at the origin permittivity goes as the inverse square of 'r'. . . . . . . . . . . . . .This business of proper time is strange. If the twin of the usual paradox returns after human culture has disappeared and there is no way to refuel and reprovision, they may not get to live out much more proper time at all! Those approaching an EH feel perfectly fine until tidal forces bum them out, but yes they have seen things asymptotically speeded up, looking out, and if this scenario is embedded in a universe of finite life, they don't get in. The last if is a gigantic mess! What'n'ell is embedded where? Would someone else please bail me out? I a.m g.e,t.t.i.n.g____ c.l.o.s.e____ a..n..d____ m..y____ s...i...g...n...a...l...s_____ w....i....l....l_____ b.....e_________ g.....e.....t......t......i......n......g___________ s.......p.......a.......c.......e.......d _____________ o........u..........t_________________ b..............a..............................d.............

[s pepperchin]

If the particle is falling into the black hole it would be accelerating and not in an inertial frame.

[anglepose]

after the event horrizon the the obzerver would see only black

and the experiencer would experience nothing for time gravity everything stops in a black hole, as the time space continuem breaks collapses in the black hole

[Apeofman]

I've been under the impression that gravity at the center of the earth cancels out. A sentient being in a habitable room there, would experience weightlessness.

 

Can anybody assure me if that impression is correct, or explain why not?

Thank you!

[s pepperchin]

I've been under the impression that gravity at the center of the earth cancels out. A sentient being in a habitable room there' date=' would experience weightlessness.

 

Can anybody assure me if that impression is correct, or explain why not?

Thank you![/quote']

 

That is correct you would be weightless at the center of the Earth.

 

The reason for this is that the weight you feel is the force the earth exerts on you:

 

[math]F_{Earth} = \frac{GMm}{r^2}[/math]

 

although this suggest that as r-> 0 that [math]F_{Earth}[/math] would go to infinity when we look at what is actually going on we see that your center of gravity is at the same point as the Earth's center of gravity, and so neither of you are pulling the other in any direction.

 

The complete explanation for this is that when you look at the world as a perfect sphere and do a little calculus the only mass that is taken into consideration when determining the force of gravity a mass exerts on another mass only the amount of mass that is a distance less than or equal to r is taken into account. It all has to do with Gaussian surfaces.

[Apeofman]

That is correct you would be weightless at the center of the Earth.

 

The reason for this is that the weight you feel is the force the earth exerts on you:

 

[math]F_{Earth} = \frac{GMm}{r^2}[/math].......

 

Thank you for such a clear well informed answer.

 

By the same token, i wonder if i would be correct (in the light of current knowledge ) to believe that the same weightlessness might also be experienced at the center of a black hole, despite the apparent break down of physical laws, at or beyond the event horizon.

[timo]

By the same token, i wonder if i would be correct (in the light of current knowledge ) to believe that the same weightlessness might also be experienced at the center of a black hole, despite the apparent break down of physical laws, at or beyond the event horizon.

No for two reasons:

1) Black Holes are strongly tied to relativity. Newtonian Gravity (which is where the F=GmM/r² comes from) does not describe black holes.

2) Even for a similar construction in Newtonian Gravity (which would be pretty boring without because it didn´t have an event horizont or any other of the interesting effects of a black hole) this would not be true. The actual reason for weightlessless at the center of earth is what s_pepperchin mentioned as "the complete answer": The fact that the parameter M you plug into the equation and therefore also the resultant force approach zero as you come closer to the center. This would not be true in the newtonian analogon of a black hole where M would be constant and the magnitude of the force would increase as you came closer to the center.

 

We have a thread with the "complete answer" in Newtonian Gravity lying around somewhere in these forums (let´s see if I can find it...). In GR, you´d first have to define what you actually mean by "gravity" but you´d most probably run into the "is not defined at the singularity"-problem for any reasonable definition.

 

EDIT: There´s the thread: http://www.scienceforums.net/forums/showthread.php?t=17027 . Not exactly what I was looking for but it should still be an interesting read.

[Apeofman]

No for two reasons:

1) Black Holes are strongly tied to relativity. Newtonian Gravity (which is where the F=GmM/r² comes from) does not describe black holes.

2)..

Right. Look's like i've got some reading to do. Thank you for answer and link.

 

Every time i find an answer to one question, a multiple of new ones come into existence.

[swansont]

Yes. For a spherically symmetric system, the gravitational force only depends on what is inside of the radius, R. (However, the relativistic dilation effect depend on the gravitational potential, which is not zero.)