Does Time ever run backwards: Perhaps.

Stick to your fairy tales sonny, and like rajesh just ignore all authoritive links, which you fail to supply yourself....
In the mean time grow up.........
https://en.wikipedia.org/wiki/Relative_direction

Since definitions of left and right based on the geometry of the natural environment are unwieldy, in practice, the meaning of relative direction words is conveyed throughtradition, acculturation, education, and direct reference. One common definition of up and down uses gravity and the planet Earth as a frame of reference. Since there is a very noticeable force of gravity acting between the Earth and any other nearby object, down is defined as that direction which an object moves in reference to the Earth when the object is allowed to fall freely. Up is then defined as the opposite direction of down.
In most cases, up is a directionally oriented position generally opposite to that of the pull of gravity.

 

Log in or Sign up to hide all adverts.

Your usual lack of proper knowledge as pointed out many times in the past is sad. Your total Intellectual dishonesty is sadder.
http://jila.colorado.edu/~ajsh/insidebh/waterfall.html
A more insightful way to conceptualize how a black hole works is to picture space as flowing like a waterfall into the black hole. At left is a movie of Boulder Falls that I photographed. Here's the movie with sound.
Imagine light rays, photons, as fishes swimming fiercely in the current. Outside the horizon, space is falling into the black hole at less than the speed of light (or the speed of fishes), and photon-fishes swimming upstream can make way against the flow. At the horizon, space is falling into the black hole at the speed of light. At the horizon a photon-fish swimming directly upstream will just stay there, swimming like crazy, but not going anywhere, the inward flow of space exactly canceling the fish's motion. Inside the horizon, the space waterfall falls faster than the speed of light, carrying everything with it. However hard it tries to swim upstream, the photon-fish inside the horizon is carried by the flow of space inevitably inward to its ultimate fate.

In the image at right, the (happy) fish upstream can make way against the current, but the (sad) fish downstream is swept to the bottom of the waterfall. This picture was drawn by my daughter Wild, and provided the cover image for the June 2008 issue of the American Journal of Physics4.

Doesn't relativity say that nothing can go faster than light? It is true that nothing can travel through space faster than light. However, in general relativity, space itself can do whatever it likes.

The idea of space moving is one that you may have met before in cosmology (the study of the Universe at large), in the notion that the Universe expands.


The picture of spacing falling into a black hole has a sound mathematical basis, first discovered in 1921 by the Nobel prize-winner Alvar Gullstrand2, and independently by the French mathematician and politician Paul Painlevé3, who was Prime Minister of France in 1917 and then again in 1925.
It is not necessary to understand the mathematics, but I do want to emphasize that, because the concept of space falling into a black hole is mathematically correct4, inferences drawn from that concept are correct.

The Gullstrand-Painlevé metric is

ds2=−dt2ff+(dr−vdtff)2+r2(dθ2+sin2θdϕ2)
which is just the Schwarzschild metric expressed in a different coordinate system. The free-fall time tff is the proper time experienced by observers who free-fall radially from zero velocity at infinity. The velocity v in the Gullstrand-Painlevé metric equals the Newtonian escape velocity from a spherical mass M
v=−2GMr−−−−−√
with a minus sign because space is falling inward, to smaller radius.
Physically, the Gullstrand-Painlevé metric describes space falling into the Schwarzschild black hole at the Newtonian escape velocity. Outside the horizon, the infall velocity is less than the speed of light. At the horizon, the velocity equals the speed of light. And inside the horizon, the velocity exceeds the speed of light. Technically, the Gullstrand-Painlevé metric encodes not only a metric, but also a complete orthonormal tetrad, a set of four locally inertial axes at each point of the spacetime. The Gullstrand-Painlevé tetrad free-falls through the coordinates at the Newtonian escape velocity.

It is an interesting historical fact that the mathematics of black holes was understood long before the physics. Einstein himself misunderstood how black holes work. He thought that the Schwarzschild geometry had a singularity at its horizon, and that the regions inside and outside the horizon constituted two separate spacetimes. I think that even today research into general relativity is too often dominated by abstract mathematical thinking at the expense of conceptual understanding.

 

Log in or Sign up to hide all adverts.

No, I'm 100% correct.
Sorry, you ain't having much luck.

http://curious.astro.cornell.edu/ou...you-see-from-inside-a-black-hole-intermediate

Now if we assume not only that we haven't died on the way into the black hole, and that we can see the light which has an infinite blue shift we would be able to see some weird things. If we looked away from the singularity at the centre of the black hole we would be able to see the whole universe in one small patch of our sky - even the stuff that is actually behind the singularity! Also time outside would appear to be running much faster, so we would be able to see the evolution of the universe "flash" before our eyes.

Keep trying.

Please Register or Log in to view the hidden image!

 

Log in or Sign up to hide all adverts.

Your post 81 and 82 has no meaningful or relevant content, so does not call for any rebuttal.

and then what? is it one shot or slow motion or replay or at some adjustable flow rate? what is the utility of seeing the 14 billion years in a flash? You say this is not testable and then say it is 100% correct? Give some reasonable argument, please.

 

Of course all you need do is come up with a reputable link of your own.
I mean you are only an amateur just like myself, so you need to re enforce that amateurish status with some reputable links.
In the mean time I'll see what more info I'm able to obtain and I'll try and get some more expert opinion.

 

Translation:
I am unable to refute the reputable links you have supplied.

It may not be testable, but just as per the old argument you put up re assigning properties to inside a BH, the laws of physics and GR allow us to reasonably give properties such as spin of spacetime as well as mass with a Kerr metric BH.
But we have done all this before, have we not? and many expert professional opinions refuted your unusual take on BHs.
Please don't make me go and recover all the relevant replies....

Please Register or Log in to view the hidden image!

 

Your continued obsession with that poster rajesh, is irksome, despite earlier warning. I am sorry you have provided no argument worthwhile which requires any rebuttal.

Since you have been speaking about reputable links to me and in one another thread to Schmelzer, then let me put something on record....

With reference to some reputable links, both the sides

A. Must agree that the link provided is reputable, the simple criterion is that it is some scientific paper or journal or some publication. It should not be science journalism for general public.

B. Once the above is established, now it is the question of interpretation of the contents by both the sides.

Your wiki reference to Gravity being down direction, passes the first condition, and now the issue is interpretation by you and me. Your interpretation (rather lliteral acceptance of what is written there) that 'Gravity is down direction' is non scientific, ok to explain the earth specific direction of gravity to primary school children. Science has no space for Up - Dn, Left-Right, North-South, East West etc. As I told you a simple understanding of coordinate system will help.

 

You see your problem is as it always has been and as Prof Link and others have pointed out to you.
But I'll answer the above again anyway, particularly your false premise above.
You may fall into a BH, what you are forgetting of course is that photons/light from the Universe surrounding BH, are already streaming in. Much as for example if someone switched Alpha Centauri off tonight, we will still be seeing its light hitting our eyes for another 4.5 years.
Even you should be able to see that.
But please, as I have already asked, on any of the points and the arguments you have falsely fabricated, please show some reputable reference supporting your view.
I mean I certainly do not as a lay person expect people to just automatically agree with me, hence my many links on the relevant.
So likewise yourself as a lay person, should need to support what you claim as true by reputable links.
Now that's not too much to ask, is it?

Let's look at those three points that you seem to have difficulty with....
[1] The possibility of time running backwards. Based on the known facts that time slows at it approaches "c" and stops at "c" , to say it would flow backwards is not too big of a call inside the BH where spacetime flows >"c".
No we are unable to test that, but once again, we are logically within reason, allowed to apply properties inside a BH, on the know laws of physics and GR outside the BH.
That of course was validated by around three experts including Prof Hamilton.

[2]A person falling inside a BH, as already explained, can certainly see the Universe as described that exists beyond the EH, due primarily to gravitational lensing, and your obvious mistaken belief that the EH is some sort of physical barrier. Also again supported by a couple of links.

[3]The third, the most obvious is that gravity does denote the direction down, despite your false indignation opposing that.
Again that is also supported.

 

But you are unable to refute any of those facts. rajesh was a fool...you seem a lot like him.

Let me tell you something. As long as you refuse reputable links, and put your own refuted, unevidenced and unsupported take on BHs, you will be treated as always.
As an amateur, you should supply links to support your stuff, simple as that.
We have no reason to accept what you say as gospel as you are a total lay person as am I.


PS: Just a quick point......
Obviously anyone falling into a BH will be overcome by tidal gravitational effects, which will see them literally spaghetified and the atoms in their body torn asunder by gravity. In essence gravity overcomes all other forces including the strong nuclear.

 

That has been an obvious ploy of yours with your many forays into this forum, when questioned about some interpretation that you see as fact.
Someone once said [could have been Einstein] "That if you are unable to explain it to a child, you do not understand it yourself" or words to that effect.
As a lay person I do my utmost best to explain something as simply as possible.eg: the fact that gravity denotes down. Yet even for something as simple as this fact, you want to project that which you have tried to project in all your forays here...that being that you are some qualified learned individual with no peers on this forum or anywhere else [evidenced by your total ignoring of advice from people like Prof Link, Prof Begalman and Prof Hamilton]
We all know better but, don't we? Such unbridled arrogance on your part.

Admittedly WIKI is not the be all and end all of reputable links, so on this matter I looked for more........
http://sciencequestionswithsurprisinganswers.org/2013/10/10/why-is-there-no-up-and-down-in-space/

Why is there no up and down in space?
Category: Space Published: October 10, 2013

Please Register or Log in to view the hidden image!

Public Domain Image, source: NASA.
There is an up and down in space. "Down" is simply the direction gravity is pulling you, and "up" is just the opposite direction. Since there isgravity everywhere in space, there is also an up and down everywhere in space. Gravity is a centrally attractive force, so "going down" means falling or being pulled towards the center of the nearest massive object. If you are in space and the earth is the nearest astronomical object, you fall towards earth. Down is therefore towards the earth's center and up is away from the earth's center when close to the earth. Down is not towards the earth's South Pole and up is not towards the earth's North Pole. This mistaken notion comes from the way we traditionally hold flat maps. The Nile river would never flow north if north were really up. Unfortunately, in an effort to explain why north is not up and south is not down, many people conclude there is no up or down in space, which is clearly wrong. If earth is the closest large body, down is always towards the center of the earth and up is always away from the center of the earth. Nothing magical happens if you are leave earth's surface and board the International Space Station: down is still in the same direction.

But if you look at the astronauts on the International Space Station, they seem to be floating around with no sense of up or down. This interesting behavior is not due to a lack of gravity, but is due to the fact that they are in free fall. When falling freely, our human senses cannot detect which way is down. But there still is a down, evidenced by the fact that you are accelerating in the down direction while falling. If you jumped into an empty elevator shaft from the fiftieth floor and closed your eyes as you fell, you would not be able to tell which way is up (ignoring air resistance). The gravity did not magically disappear in the elevator shaft just because you closed your eyes and jumped. The down direction is still very real and is evident from the fact that you are falling in that direction, even if you can't feel which way is down. It is the same with astronauts in orbit. The round path of their orbit is a direct indication that they are falling and that they are experiencing a down (which is towards a focus of their orbit), even if they can't feel it while in a state of free fall.

What would happen if you got far enough away from the earth that its gravity were no longer significant? Then you would simply fall towards whatever body has the strongest gravity. Near the moon, down is towards the moon. Near Saturn, down is towards Saturn. If you are not particularly close to any planet but are still in the solar system, down is towards the sun (the barycenter, actually), because that is the direction gravity is pulling you. If you start at rest relative to the sun and are far away from the planets, you will fall towards the sun. If you go out of our solar system and do not enter another solar system, down is towards the center of our galaxy. If you get out of our galaxy and don't enter another galaxy, down is towards the center of our cluster of galaxies. If you get far enough away from our cluster of galaxies, down just becomes towards the next closest cluster. All matter in space is constantly falling down. Space is so big that this falling down motion is so slow that on an astronomical scale that we don't notice it much. But it is definitely there. Because the falling of spaceships, moons, and planets looks much slower on astronomical scales than you falling off your roof, scientists don't use the word "falling" much. Instead they talk about "orbits", "trajectories", and "paths". Whenever they use such terms, they really just mean "things in space falling down".


Or another by NASA
http://science.nasa.gov/science-news/science-at-nasa/2001/ast07aug_1/
The above expertly explains how when gravity is negated say by free fall/orbits, then so to is up and down.


The other two scenarios you questioned were slightly more then lay person orientated so I suppose one could understand why you were confused on those issues.
But this gravity question is really just primary school stuff, and one can only surmise that your angst towards me is a result of me being a party in showing your refuted paper and other issues in the past, as in gross error, and that this is still seething and bubbling beneath that arrogant facade of yours.

What you really mean to say is that when gravity is absent or negated, we have no inkling of up or down. But add gravity and the problem is solved.
Space travelers in science fiction rarely have such problems. On Star Trek's USS Enterprise, for example, artificial gravity provides direction cues for the crew. Captain Kirk never gets out of bed upside-down.

 

I was advised against referring to you as rajesh by name. I have not done that.
My claim though that you are he, stands on even firmer ground.

Most of my links are from learning institutions and stand as reputable.
It is not for you to judge otherwise simply on the basis that they refute your own claims.

See my previous post and my comment in being able to explain it to children to really understand it yourself.

 

http://jila.colorado.edu/~ajsh/insidebh/schw.html
, the view of the outside Universe will not disappear as you pass through the horizon.

 

Paddoboy,

Your link says, Why is there no up and down in space? Hope you understood.

Take the center of Earth as origin, now all the particles on the surface of the Earth are pulled by Gravity towards this center of Earth, so there are infinite such radial lines and directions. Would you call all of them as down direction? Yes, to explain to primary school children about the Gravity pulling downwards (like that Newton's apple), but in exact science it has no meaning.


I see the same hopelesness of getting into argument with you as observerd by Schmelzer in another thread. Your reliance on popular science is too much. As he said, which is a fact also, these popular science presentations are with certain inaccuracies, more or less ok but meant for lay audience. The problem is not these inaccuracies, these are understandable, but the problem is when a lay reader lacking sound grasp on the subject presents these presentations as scientific facts. Thats what you are doing. A person who misses the boat on the direction aspect (most fundamental to Physiscs where we are discussing SR/GR and frame of ref and coordinate system play the crucial role) is not worthy of engagement on the complex topics like Hawking Radiation, Quantum Fluctuations, Thermodynamic Time etc. Sorry Paddoboy, I am being bit harsh, but then I have not seen any motivation in you to learn the finer aspect of the subject. You are more than happy with your popular science ideas, but please do not push them verbatim as mainstream science.

 

The link says when you have no gravity you have no direction. Inferring correctly that gravity denotes down.

I give most on this forum enough sense to know what the articles said. I don't need to worry about that.
My job is done here, when I can show you for what you are, another obvious point to most on this forum I would suggest..