Quantum/Relativitiy and the Speed of Light Paradox

[Grotug]

Big bang suggests that there was only a concentrated mass.was there no space?If there was no space where did it come from?[i mean what makes space?].time also started after big bang.how did it start?
Don't u guys think there's somethin missing in this theory?

The holy grail of physics [at present] is to unite general relativity with quantum mechanics - quite a challenge. I think both theories are good approximations, but, incomplete. Until we figure out the incomplete parts, unification is not possible.

In my opinion the key to dealing with the current cosmological problems require applying some of the ancient spiritual Philosophies like buddhism.

As I understand the big bang:
Nothing can travel faster than light. Light travels at 2.998E^8m/s. The universe is accelerating at an increasing rate.

Paradox number 1: the big bang was expanding extremely fast at the very beginning and its rate slowed. If this is true, how can the universe now be expanding at an accelerating rate?

Just how fast was the universe expanding in the beginning? How fast is it expanding right now? Will its rate of expansion be limited by the speed of light? Is there any evidence that the rate of expansion at the beginning was greater than the speed of light? How do these questions fit in with the non-synthesizing qualities of General Relativity and Quantum Mechanics? What would Einstein say?

Time slows down as you approach the speed of light. If I understand it right, the relationship between the speed of light and time is an inverse relationship. That is, the faster something goes, the slower the time passes for it. Is there a simple graph that shows this relationship? Is it linear, quadratic, exponential or something else?

Since light is always traveling at the speed of light then we can conclude that it is ageless? That is, light... all light... is still as young as the point of its creation at the Big Bang?

How does light travel if time never passes for it? Isn't change and thus movement a function of the time/space continuum? Don't you need the passage of time for change to take place? But time does not pass for light, so how can light travel? let alone at some specified constant in space and time? Light is in space, but is it in time? Is it not timeless and ageless?

In Buddhism and other enlightenment philosophies, the goal is to escape the physical world and become "One" (with the universe) in a state of bliss where there is no time and space--sort of analogous to becoming light. Does it make sense to consider ancient spiritual philosophies when trying to come up with a better understanding of the gestation of the universe and what was 'before' the big bang? Does it make sense to consider such philosophies in trying to unify Quantum Mechanics and General Relativity?

What other implications are there for the fact that light is always traveling at the speed of light and thus time is never passing for it? Again, can I accurately state: light exists in space, but not in time?

 

[bapowell]

Cosmology is described by Einstein's General Theory of Relativity (GR). Much of your confusion stems for your application of Special Relativity to the problem. In GR, it is possible for distant objects to recede from each other at speeds surpassing that of light simply because the space between them is expanding. The more space between them, the faster their recession velocities. Nothing fancy here -- just Hubble's Law. Right now in our universe there are galaxies that are receding from each other at speeds > c. So yes, it can -- and does -- happen.

Your paradox number 1 is not a paradox, at least not to any practicing cosmologist. The expansion of the universe is driven by its energy and matter content. As the universe expands, the densities of the different components of matter and energy change -- matter and radiation dilute (albeit at different rates) which effects the expansion rate. Other, more exotic forms of energy, such as a cosmological constant if it exists, will necessarily come to dominate at late times. From Einstein's Equations, we see that a cosmological constant gives rise to an accelerated spacetime. Nothing paradoxical here -- all perfectly consistent with the standard application of GR.

Your question of how/whether time passes for light is a thoroughly explored topic, and much time has been spent discussing it on this very forum. You should do some digging.

Understanding the universe is a scientific endeavor, i.e. we seek natural explanations for the phenomena that we observe. Defaulting to religion precludes any hope of doing this as it is inherently super-natural, non-scientific (untestable, nonpredictive), not bound by logic, and good luck unifying Buddha with quantum mechanics...yikes!

Modern cosmology is incapable of addressing what happened before, or even *at* the big bang. And it doesn't purport to address these things. You can apply whichever dogma you wish to pre-big bang cosmology, but it's not science.

 

[twofish-quant]

In my opinion the key to dealing with the current cosmological problems require applying some of the ancient spiritual Philosophies like buddhism.

I'm a practicing Buddhist and this is non-sense. The core belief of Buddhism is that sensory data is an illusion and should be ignored which is quite opposite of the way that you do science.

In Buddhism and other enlightenment philosophies, the goal is to escape the physical world and become "One" (with the universe) in a state of bliss where there is no time and space--sort of analogous to becoming light. Does it make sense to consider ancient spiritual philosophies when trying to come up with a better understanding of the gestation of the universe and what was 'before' the big bang? Does it make sense to consider such philosophies in trying to unify Quantum Mechanics and General Relativity?

No. It doesn't.

 

[Tanelorn]

Dr. Buddy Rydell: He was wondering how a man weighing 600 pounds could teach people about self-discipline.

 

[Grotug]

Thanks bapowell for the reply. I wasn't wanting to resort to religion, more like to general pop-culture ideas of spirituality or philosophies. For me physics ultimately becomes a philosophical question. But that's coming from someone who formally struggles a great deal with physics :-/. Sure we can gain a better understanding of the physical world and the origin of physics/the universe and the future of the universe, but it's also interesting to ask why matter in the first place? Why intelligent life? What is stuff and why? Why consciousness at all?

Another interesting point to bear: is it possible for non existence if there is existence? Can something come from nothing? As another poster expressed his/her intense burning to know whether the universe is finite or not (an interesting thread as far as I can follow it) I have long wanted to know how to grapple with the ideas of both existence and non-existence: how, logically, can they both exist (philosophy is all about logic ultimately). How can something come from nothing? Either there was always something or there is nothing and that's it--something will never come from nothing. To me you can't have it both ways; there was either nothing or there was something. Since we have something, then that's what is. There is no non-existence. something, whether it's matter or consciousness or something else, has always and will always exist (yikes); it may transmute forms etc., but, like the laws of conservation of energy, I guess I'm proposing a law of conservation of existence :P. Once Is, always Is. Never was not.

Are there really 'shades' of consciousness? How does that work? If there has aways been something, the next question for me is whether consciousness and matter are somehow interconnected. The assumption is that consciousness came from matter. But we don't really know that. It's just a presumption that people, and I suppose more so, scientists, aren't very interested in, or don't find very important to understanding the physical world, despite the fact it is their consciousnesses that they are using to understand anything at all. Seems like you might want to better understand the nature of the tool you are using to measure and understand the world you are living in. To me it seems it changes the playing field considerably if you suppose that matter came from consciousness (as civilizations have believed for as long as records go back). It may allow for new ways of thinking about current cosmological problems (I'm not suggesting cop out-non provable/testable hypotheses), but it might add another dimension, as it were, to thinking about the problem; provide novel and different ways of looking at and thinking about cosmological problems.

I'd very much like to read some salient threads on speed of light/age of light/time. I'll see what I can turn up.

 

[Grotug]

I'm a practicing Buddhist and this is non-sense. The core belief of Buddhism is that sensory data is an illusion and should be ignored which is quite opposite of the way that you do science.

When I did a 10 day course on Buddhism in Bodh Gaya, the monk teaching us stressed that the only truly important thing for a person to do in life is to attain enlightenment, and thus the cessation from suffering. Negating sensory data is a major principle in moving towards enlightenment. At least that's what I got from the Buddhist retreat I experienced. I can't really imagine what enlightenment is; of being in constant bliss, but doing nothing (as in worldy things) and not being in the physical world. I was suggesting we ask whether we can learn something from these kinds of philosophies, of trying to escape this universe in lieu of something else (again, what is enlightenment? what is the 'else'?) Might gaining a better understanding of this different way of looking at life, the universe, the purpose of existence, prompt the scientist to look at problems differently--to ask different questions relevant to the mysteries? It doesn't mean you have to put the math away and latch onto some new-age pseudo-religious-crackpot theory about the universe that makes you feel all warm and fuzzy inside. I just wonder whether tackling cosmological problems from a purely matter of matter stand point is ultimately limiting. (Pardon the pun).

 

[KillerVamp09]

If anyone has posted this already my bad.
You stated that nothing can travel faster than light, but the universe is traveling faster than light. No matter can travel faster than light, but the fabric of space-time can expand faster than light because it is not made of conventional matter. Hence space-time can increase as fast as it want and still obey the universal speed limit. This might be confusing because as it has occurred to me that people think the matter in the universe is traveling faster than light when talking about an ever expanding universe; this is not true the expansion of space-time can occur faster than the speed of light, as the matter within space-time remains at its current velocity. Meaning that space-time accelerates in expansion and matter remains at its current acceleration. Space-time cannot pull matter or push matter it is simply the fabric on which our universe is laid upon.

 

[Peter N-H]

In GR, it is possible for distant objects to recede from each other at speeds surpassing that of light simply because the space between them is expanding. The more space between them, the faster their recession velocities.

I happened upon first this site, and then this particular page, because I've been searching for an answer to something that puzzled me.

Having read several titles on cosmology and mathematics during this year intended for the average non-specialist and non-mathematical reader, I found myself particularly struck by the idea that a few billion years from now the night sky will begin to go dark as light sources accelerating away from us exceed the speed of light, and that had we not already evolved to the point of being able to make telescopes and discuss physics there would be no way for us ever to know that these light sources (stars, galaxies) had ever existed.

Yet the maximum speed at which information or anything else can travel is repeatedly said to be the speed of light, so how is it possible that vast amounts of matter will manage to achieve that?

What you have said in reply to the original query appears to be an answer to that, but it is not one of which I've been entirely to make sense. If everything in the night sky is moving away from us (because everything is moving away from some original point at increasing speed) in what sense is the space between us and any receding object expanding except in the everyday sense that we are getting further apart as a result of differing speeds and differing directions of motion?

If you could expand your explanation so as to make this more clear, I'd be most grateful.

 

[George Jones]

Speed depends on how distance is defined.

In special relativity (flat spacetime), there is a standard definition of (spatial) distance that can be applied both locally and globally. In other words, this definition of distance applies to nearby objects, and to objects that are far away. Speed is change in distance divided by elapsed time, so this standard definition of distance can be used to calculated speeds of objects that are near and far. Speeds of objects, near and far, calculated in this way always have the speed of light as their speed limit.

The situation in general relativity (curved spacetime) is far different. Because of spacetime curvature, the definition of (spatial) distance used in the flat spacetime of special relativity can only be applied locally, just as the Earth looks flat only locally. This leads to speeds of nearby objects that limited by the the speed of light, but it say nothing about the behaviour of objects that are far away.

Even though the special relativity definition of distance cannot be applied globally in curved spacetime, there is a standard cosmological definition of distance that is used in the Hubble relationships. Strangely, this cosmological definition of distance can be applied to the flat spacetime of special relativity (Milne universe), and when this is done, it produces a definition of distance (for special relativity) that is different than the standard definition of distance in special relativity!

A different definition of distance gives a different concept of speed, since speed is distance over time. This alternative definition of speed, even within the context of special relativity, produces speeds of material objects that are greater than the standard speed of light! In other words, this definition of speed produces, in both cosmology and in special relativity, speeds that are greater than the standard speed of light.

If v is standard speed in special relativity, and V is cosmological "speed" applied to special relativity, then some corresponding values (as fractions of the numerical value of the standard speed of light) are:

  v                   V
0.200                0.203
0.400                0.424
0.600                0.693
0.800                1.10
0.990                2.65

Even though there can be different definitions of spatial distance, there is no ambiguity with respect to the prediction of experimental measurements. One just has to keep in mind what definition is being used.

 

[twofish-quant]

Sure we can gain a better understanding of the physical world and the origin of physics/the universe and the future of the universe, but it's also interesting to ask why matter in the first place? Why intelligent life? What is stuff and why? Why consciousness at all?

Those are interesting questions, but one in which I don't think physics can be useful. Physics is useful because you intentionally reduce the questions that you try to answer.

Another interesting point to bear: is it possible for non existence if there is existence? Can something come from nothing?

If you want to work this as a physics problem you have to rigorously define "non-existence", "existences", "something", "nothing". Once you've defined those terms mathematically, you can pretty quickly figure out the answer. Now it may turn out that the mathematical definition of "thing" may be different from the ordinary intuitive definition of "thing" but at that point you are in the world of linguistics and philosophy and out of the realm of physics.

How, logically, can they both exist (philosophy is all about logic ultimately). How can something come from nothing?

Simple. You define "thing" and "nothing" so that "something" can come from "nothing". Also the statement that philosophy is all about logic is something that a lot of people will disagree with. Personally, I think that philosophy is more about "feeling" than about "logic" which is why science and math are pretty much useless for the more important questions in life.

[q]Either there was always something or there is nothing and that's it--something will never come from nothing. To me you can't have it both ways; there was either nothing or there was something. Since we have something, then that's what is. There is no non-existence. something, whether it's matter or consciousness or something else, has always and will always exist (yikes); it may transmute forms etc., but, like the laws of conservation of energy, I guess I'm proposing a law of conservation of existence :P. Once Is, always Is. Never was not.[/q]

That's not science. It's not math. I don't think what you just did is particularly useful.

[q]The assumption is that consciousness came from matter. But we don't really know that. It's just a presumption that people, and I suppose more so, scientists, aren't very interested in, or don't find very important to understanding the physical world, despite the fact it is their consciousnesses that they are using to understand anything at all.[/q]

Personally, I think that consciousness has something to do with matter. If I inject myself with certain molecules, my consciousness will react is certain rather predictable ways.

[q]To me it seems it changes the playing field considerably if you suppose that matter came from consciousness (as civilizations have believed for as long as records go back).[/q]

I'm staring at the table in front of me. I'm thinking of a pepperoni pizza. I'm thinking really hard about a pepperoni pizza. No pepperoni pizza appears. Guess this matter from consciousness thing doesn't work.

That might sound flippant, but I'm making a very important point. The fact that I can try to think about a pepperoni pizza and one *doesn't* appear, tells me something deep and meaningful about the universe. Take a look at a match. That tells you something about the beginning of the universe.

Provide novel and different ways of looking at and thinking about cosmological problems.

You really don't want novel and different. You want same and boring.

 

[twofish-quant]

Yet the maximum speed at which information or anything else can travel is repeatedly said to be the speed of light, so how is it possible that vast amounts of matter will manage to achieve that?

What special relativity does is to divide the world into the future and the past. If you have an patch of ordinary space-time and you could send information faster than the speed of light, then it turns out that you could send a signal from the present to the past, which would be bad.

If the entire universe is expanding at faster than light, then it works out that you can't send a message to the past, so the restrictions for flat space time are somewhat loosened.

The big no-no is being able to shoot your grandfather. It turns out that with general relativity, if the universe as a whole expands, you turn out not to have any way of sending a message to the past.

 

[twofish-quant]

When I did a 10 day course on Buddhism in Bodh Gaya, the monk teaching us stressed that the only truly important thing for a person to do in life is to attain enlightenment, and thus the cessation from suffering.

I've been a practicing Buddhist for 10 years. I've given up hope of reaching enlightenment in this lifetime. Maybe I'll get enough karma points for the next. Science gets you away from enlightenment in the Buddhist sense. Science is all about interacting with matter and observation which in Buddhist philosophy is an illusion.

Negating sensory data is a major principle in moving towards enlightenment.

Which makes Buddhist philosophy fundamentally incompatible with the philosophy of science. Not that there is anything wrong with that. But being a physicist means that I have zero hope of enlightenment in this life. But that's not a bad thing since in Buddhist thought, one life is just part of a cycle of rebirth.

Of course it could be that Buddhism is all wrong, and after I stop breathing there is nothing left for me but being worm food. I don't spend too much time thinking about this, since I'll find out what the situation is a few decades.

I was suggesting we ask whether we can learn something from these kinds of philosophies, of trying to escape this universe in lieu of something else (again, what is enlightenment? what is the 'else'?) Might gaining a better understanding of this different way of looking at life, the universe, the purpose of existence, prompt the scientist to look at problems differently--to ask different questions relevant to the mysteries?

Other than poetic inspiration, there really since anything there. In Buddhist thinking, I really shouldn't be doing what I'm doing. Oh well. If Buddhist is right, then I'll have many, many more lifetimes to change. If it's not, then not...

I just wonder whether tackling cosmological problems from a purely matter of matter stand point is ultimately limiting. (Pardon the pun).

Matter is more complex than it first appears. Matter and energy are really part of the same thing. But it is quite limiting, and its intended to be limiting.