Stephen Hawking: Big Bang an inevitable consequence of the laws of physics

[|iR|Focalor]

Another thing that I would like to be enlightened is reagrding to the speed limit of the universe.

Correct me if Im wrong. Nothing goes faster than the speed of light. Theoritically if your on a space ship as you approach light speed time slows down. Upon reaching lightspeed, time stops. So grating that we will equate lightspeed as zero in a number scale. However if granting you can really go faster than the speed of light, time goes backward (like a time machine going back to the past).

Now in relation to the above, the big bang started from something infinitely small and expanded (exploded) to something like the size of a ball in a billionth of a billionth of a billionth of a second. Thus Its effective expansion rate was moving way faster than the speed of light.

So if my understanding was correct, what happened to the Law of Physics regarding the universal speed limit?

Secondly, moving faster than lightspeed, wouldnt that expansion comes in a loop?

This is kind of what I was talking about. It doesn't take a person with a high IQ to understand that time itself does not stop or move backwards just because the person is moving faster than the speed of light. If I travel at the speed of light or faster, my heart will continue to beat and my body will still age normally. What I observe around me as I move towards or away from an object may seem to move backwards in time or forwards in time at an accelerated rate, but that object is still existing within time and space itself. It just seems like a waste of time to assume or consider the theory that two objects can exist within an infinite point in the same location. Perhaps math might support the idea that it's possible, but physics deals with matter and energy, things which can be observed. I don't see the idea of observing and manipulating "alternate realities" ever becoming a possibility... and I'll explain what I mean. Perhaps someone else might have a contradicting observation, and I'd love to hear it.

One could theorize that if they were to move away from an object at 10 times the speed of light, they could effectively cause that object to travel in reverse through time. If you then had a teleporter that could beam you back to that object within a fraction of a second, you will still not cause that object to go back in time due to the fact that the object itself exists within time and space and is itself subject to it. Time itself has not stopped. From what I recall, the theory about alternate realities and dimensions is basically using the principle of moving away from an object faster than the speed of light to make it go back in time, and then effect a change before that previous point at which you initially observed it happened. Like I said, impossible. If I move faster than light, my will heart not beat in reverse. Due to the physical energy exerted on my body by it traveling at that speed, some changes to it may occur, but time itself will not be effected.

As I understand it, that's the integral part of this theory about what happens to matter consumed by a black hole. Saying that it doesn't matter that the particles consumed by it seem to no longer exist because in an alternate dimension the black hole itself doesn't exist... seems like a lame cop out no lamer than claiming God created the universe.

[quadz]

Another thing that I would like to be enlightened is reagrding to the speed limit of the universe.

Correct me if Im wrong. Nothing goes faster than the speed of light. Theoritically if your on a space ship as you approach light speed time slows down. Upon reaching lightspeed, time stops. So grating that we will equate lightspeed as zero in a number scale. However if granting you can really go faster than the speed of light, time goes backward (like a time machine going back to the past).

Quoting from: http://en.wikipedia.org/wiki/Speed_of_light

"According to special relativity, the energy of an object with rest mass m and speed v is given by γmc2, where γ is the Lorentz factor defined above. When v is zero, γ is equal to one, giving rise to the famous E = mc2 formula for mass-energy equivalence. Since the γ factor approaches infinity as v approaches c, it would take an infinite amount of energy to accelerate an object with mass to the speed of light. The speed of light is the upper limit for the speeds of objects with positive rest mass."

Now in relation to the above, the big bang started from something infinitely small and expanded (exploded) to something like the size of a ball in a billionth of a billionth of a billionth of a second. Thus Its effective expansion rate was moving way faster than the speed of light.

So if my understanding was correct, what happened to the Law of Physics regarding the universal speed limit?

Quoting from: http://en.wikipedia.org/wiki/Metric_expansion_of_space

"While special relativity constrains objects in the universe from moving faster than the speed of light with respect to each other, there is no such theoretical constraint when space itself is expanding. It is thus possible for two very distant objects to be moving away from each other at a speed greater than the speed of light (meaning that one cannot be observed from the other)."


Regards,

quadz

[quadz]

It doesn't take a person with a high IQ to understand that time itself does not stop or move backwards just because the person is moving faster than the speed of light.

For me, relativity is fairly non-intuitive, and it only seems more confusing by bringing IQ into it.

It's not at all clear to me that if a person could reach C, that they would not indeed be frozen in time from the perspective of a stationary observer.  On the contrary, I would expect that to be the case.

But: it seems to me the real problem is trying to debate the relativistic effects of a situation that is impossible within a relativistic framework.  Relativity already explains why it would require infinite energy to accelerate a 'person' to the speed of light, so we shouldn't be surprised that weird results pop out of the equation (time stops or goes backward) when we feed impossible inputs into it (object with mass accelerated to C or accelerated beyond C.)


Regards,

quadz

[reaper]

I don't think it's possible to travel back in time as far as we are concerned.  This shit is way over my head though.

 

[yahoo]

I don't think it's possible to travel back in time as far as we are concerned.  This shit is way over my head though.

Hawking said that tie travel may be possible but only to the future. Traveling to the Past creates a paradox that would sum up to total chaos.
Example, If you would travel to the past and kill your Father then that would mean you wont exist to travel back in the past and so on.

He did conduct an experiment about time travel. He put out an invitation to any time traveler in the future to visit him on an exact date, time and location. Not surprisingly no one caim.

However if i remembered it right, physcist said that there a possibility of an existince of an alternate reality wherein we may exist in other dimensions. The universe we know may even be a  part of an infinite multiverse. Now think of it that there are other earths out there were we may have exist in as other individuals. Heck, In some other world out there in some other unverse Im sure Im so filthy rich.

[|iR|Focalor]

In an alternate universe... I'm drunk there too. Me and I should get together for a beer sometime. I'm sure I'm fascinating.

[yahoo]

http://www.youtube.com/watch?v=c33XTfoipv8

just follow all the parts.

[Tubby]

As I understand it, travelling faster than the speed of light (which isn't possible anyway) would only cause you to 'catch up' with visual images of an event which happened in the past: You wouldn't be 'travelling' into the past, but would simply be observing images which had eminated from a past event. So, you might see a person appear to grow younger, for example, because you are exceeding the speed at which current images of that person are eminating, and you're catching up to - and observing - images which had eminated previously from that person; i.e; from when he was younger.

The further you exceed the speed of light, the further back in time you would (falsely) appear to go as you catch up with increasingly 'older' images of the event (or the person or whatever).

So while it might indeed appear that you were moving back in time, this appearance would basically be false; somewhat analogous to the time lapse between seeing someone fire a gun at a great distance and hearing the bang several seconds later.

Just because it appears so, doesn't necessarily make it so.

[quadz]

As I understand it, travelling faster than the speed of light (which isn't possible anyway) would only cause you to 'catch up' with images of an event that happened in the past: You wouldn't actually be travelling into the past, but would simply be overtaking and observing previous images of the event. So you might see a person appear to grow younger, for example, because you are exceeding the speed at which current images of that person are eminating, and catching up to those which have gone before.

On the other hand, we've measured that the time dilation effects predicted by relativity do occur.  (with both gravitational and inertial mass)

If we accelerate an object toward C, then return it home, its clock will have diverged from ours during the journey.

So it's not enough to describe the effect in terms of overtaking old photons.  Time dilation really happens.

However...

When we describe the effects of accelerating a mass toward C, it depends which framework we use to calculate the results.

With Newtonian physics, constant acceleration takes constant energy, right up past and beyond C, no problem.

Whereas, in a relativistic framework, time dilation does occur, but the object can never reach C.

My layman's understanding is that we can't meaningfully calculate the results a mass accelerated beyond C without breaking out of the relativistic framework.  (Or pulling sleight of hand like saying the mass is imaginary, as with hypothesized tachyons.)

Thus, even though the time dilation effects are real as an object approaches C, it may not be meaningful to then ask, "ok, but what if it went faster?" in the sense that relativity doesn't provide the answer.

As I understand it we'd need non-relativistic (or at least modified) framework to talk meaningfully about what happens when a mass exceeds the speed of light?


Regards,

[Tubby]

Well, time dilation is a theoretical concept which (supposedly) only occurs at extreme ends of the physical spectrum. For example, at the event horizon of a singularity / black hole. Probably such events are beyond human comprehension at this stage, but I guess they're worth speculating about nonetheless.

Maybe we need another few thousand years of intellectual evolution and development before we can really begin to understand the concept.

idk if this thread will last that long!! 

[quadz]

Well, time dilation is a theoretical concept which (supposedly) only occurs at extreme ends of the physical spectrum. For example, at the event horizon of a singularity / black hole. Probably such events are beyond human comprehension at this stage, but I guess they're worth speculating about nonetheless.

We've already measured it.  The experimental results align well with the theory.

http://en.wikipedia.org/wiki/Time_dilation#Experimental_confirmation

[Tubby]

Well, it's one thing to measure something. Quite another thing to understand it.

Eg; I'm sure people in the Middle Ages could 'measure' the amount of rain which fell on their crops, but the fact that they attributed that rainfall to a supernatural deity (god) betrays the fact that they simply didn't understand how rain occurs as a natural climatic process.

Similarly, you can say you have 'measured' the effects of time dilation, but does that mean you can say you understand it?

[quadz]

Similarly, you can say you 'measured' the effects of time dilation, but does that mean you can say you understand it?

The fact that the measurements followed the prediction, would seem to imply some level of understanding of the properties and implications of the phenomenon.  Else the prediction couldn't have been accurately made.

To me, that's an important disctinction.

On the other hand, yeah... Feynman said, "I think I can safely say that nobody understands quantum mechanics."

[Tubby]

Similarly, you can say you 'measured' the effects of time dilation, but does that mean you can say you understand it?

The fact that the measurements followed the prediction, would seem to imply some level of understanding of the properties and implications of the phenomenon.  Else the prediction couldn't have been accurately made.

To me, that's an important disctinction.

On the other hand, yeah... Feynman said, "I think I can safely say that nobody understands quantum mechanics."

Well like they say, your guess is as good as mine.

 

[quadz]

Well like they say, your guess is as good as mine.

Probably, which emphasizes the point I'm making: people who understand these phenomena better, make more accurate guesses about them.

So your guess may be as good as mine, but their guesses are better than ours.  A lot better.

Right?