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Author Topic: What's the real speed limit of our universe?  (Read 10851 times)

Francis Tapon

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What's the real speed limit of our universe?
« on: 20/01/2009 11:30:01 »
Francis Tapon  asked the Naked Scientists:
   
Although most say that nothing can travel faster than
light, there are two exceptions:

1) Entanglement

2) The early expansion/inflation of the universe.  

In both cases, most physicists agree that something was travelling faster than light. These are the same physicists who one hour before told you than nothing can travel faster than light.

Will the real speed limit of our universe please stand up?

Francis Tapon

What do you think?


 

Offline Vern

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What's the real speed limit of our universe?
« Reply #1 on: 20/01/2009 11:44:34 »
I suspect that nothing moves faster than light; not even in entanglement or the Great Expansion. There are just some problems there that haven't yet been worked out.
 

Offline lightarrow

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What's the real speed limit of our universe?
« Reply #2 on: 20/01/2009 11:53:21 »
Francis Tapon  asked the Naked Scientists:
   
Although most say that nothing can travel faster than
light, there are two exceptions:

1) Entanglement

2) The early expansion/inflation of the universe. 

In both cases, most physicists agree that something was travelling faster than light. These are the same physicists who one hour before told you than nothing can travel faster than light.

Will the real speed limit of our universe please stand up?

Francis Tapon

What do you think?
One thing is speculation and another is established fact. The established fact is that maximum speed is c.
 

Offline justaskin

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What's the real speed limit of our universe?
« Reply #3 on: 20/01/2009 12:30:47 »
One thing is speculation and another is established fact. The established fact is that maximum speed is c.
I think the safest thing we can currently say is that mans experience is that
nothing can go faster than light even though a German scientist has claimed to have transmitted Mozart 40 at 4.7 times c via quantum tunneling.
To say it is established fact is a brave statement.
After all they said.
The Earth is flat
The Earth is the centre of the universe.
That you could not fly faster than sound.
And now nothing moves faster than light.
Just because man has not found out how to do it yet does not make it fact.
I think only one person can say how fast you can go in his universe and he ain't saying.

Cheers
justaskin
 

Offline lightarrow

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What's the real speed limit of our universe?
« Reply #4 on: 20/01/2009 12:38:04 »
One thing is speculation and another is established fact. The established fact is that maximum speed is c.
I think the safest thing we can currently say is that mans experience is that
nothing can go faster than light even though a German scientist has claimed to have transmitted Mozart 40 at 4.7 times c via quantum tunneling.
To say it is established fact is a brave statement.
After all they said.
The Earth is flat
The Earth is the centre of the universe.
That you could not fly faster than sound.
And now nothing moves faster than light.
Just because man has not found out how to do it yet does not make it fact.
I think only one person can say how fast you can go in his universe and he ain't saying.

Cheers
justaskin
justaskin, I would agree with you if it wasn't for the fact that we are talking about physics and not phylosophy or religion. In physics, if today we only know that neutrinos are massless and today we discover they are not (as it is) then, today we say that it's an establish fact that they are massless and tomorrow we will say that it's an establish fact that they are not. Do you understand the difference? Physics is not interested in "Truths" or "beliefs" but just on *experimental* results. If a person or even a physicist believes that, since neutrinos have been found massless up to now then they will be found massless even tomorrow, it's his problem, not a problem for physics.
« Last Edit: 20/01/2009 12:42:15 by lightarrow »
 

Offline Vern

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What's the real speed limit of our universe?
« Reply #5 on: 20/01/2009 12:44:29 »
Quote from: justaskin
Just because man has not found out how to do it yet does not make it fact.
I think only one person can say how fast you can go in his universe and he ain't saying.

Cheers
justaskin
Certain scenarios for the constitution of matter would assure that matter can never exceed the speed of light.
H Ziegler proposed such a construct back in 1909. The Lorentz transformations were put together around the turn of the century when most people suspected that:
Quote
The final irreducible constituent of all physical reality is the electromagnetic field.

 

Offline justaskin

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What's the real speed limit of our universe?
« Reply #6 on: 21/01/2009 02:40:03 »
Thanks lightarrow
I just don't accept that about 300,000Km/s is the fastest anything can go in this vast universe.
A couple of billionKm/s maybe but 300,000 just seems way to slow.

Cheers
justaskin
 

Offline lightarrow

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What's the real speed limit of our universe?
« Reply #7 on: 21/01/2009 08:02:02 »
Thanks lightarrow
I just don't accept that about 300,000Km/s is the fastest anything can go in this vast universe.
A couple of billionKm/s maybe but 300,000 just seems way to slow.

Cheers
justaskin
Ok, but are you aware of the fact that if you are in a starship travelling at (almost exactly) that speed you can go everywhere in the universe in a few seconds?
 

Offline justaskin

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What's the real speed limit of our universe?
« Reply #8 on: 21/01/2009 08:35:37 »
Ok, but are you aware of the fact that if you are in a starship travelling at (almost exactly) that speed you can go everywhere in the universe in a few seconds?
No!.I find that a bit hard to believe on a couple of levels.Why does light not suffer time dilation.
Secondly it would, I would have thought, make space travel rather dangerous we know that the light from distant objects has been traveling for billions of years to reach us and that that object is probably not there anymore.So if you went belting off to some far off place if it only took you a couple of seconds to get there only to find it wasn't there anymore not only that you would run the risk of smashing into things you couldn't see because they had now moved from where their light image is coming from.
And we have not been able to get anywhere near light speed to know exactly what will happen at such speed.

Cheers
justaskin
 

Offline lightarrow

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What's the real speed limit of our universe?
« Reply #9 on: 21/01/2009 12:48:43 »
Ok, but are you aware of the fact that if you are in a starship travelling at (almost exactly) that speed you can go everywhere in the universe in a few seconds?
No!.I find that a bit hard to believe on a couple of levels.Why does light not suffer time dilation.
What does it mean?

Quote
Secondly it would, I would have thought, make space travel rather dangerous we know that the light from distant objects has been traveling for billions of years to reach us and that that object is probably not there anymore.So if you went belting off to some far off place if it only took you a couple of seconds to get there only to find it wasn't there anymore not only that you would run the risk of smashing into things you couldn't see because they had now moved from where their light image is coming from.
And if you could travel at an infinite speed where would be the difference?

Quote
And we have not been able to get anywhere near light speed to know exactly what will happen at such speed.
If you are talking about time delays, it's already been experimentally proven from tens of years (particle accelerators, Hafele and Keating experiment, ecc.)
 

Offline Vern

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What's the real speed limit of our universe?
« Reply #10 on: 21/01/2009 12:58:44 »
Ok, but are you aware of the fact that if you are in a starship travelling at (almost exactly) that speed you can go everywhere in the universe in a few seconds?
No!.I find that a bit hard to believe on a couple of levels.Why does light not suffer time dilation.
Secondly it would, I would have thought, make space travel rather dangerous we know that the light from distant objects has been traveling for billions of years to reach us and that that object is probably not there anymore.So if you went belting off to some far off place if it only took you a couple of seconds to get there only to find it wasn't there anymore not only that you would run the risk of smashing into things you couldn't see because they had now moved from where their light image is coming from.
And we have not been able to get anywhere near light speed to know exactly what will happen at such speed.

Cheers
justaskin
Cheers justaskin; I put this question at ease in my mind by subscribing to an old idea that was popular back at the turn of the 20th century. That idea is: The final irreducible constituent of all physical reality is the electomagnetic field.

Now if that be the case, the reason for nature's speed limit is obvious. All things are made out of light. So, for sure, nothing can move faster than light itself can move.
There's lots of evidence to support this. Theres very little evidence against it.
 

Offline ukmicky

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What's the real speed limit of our universe?
« Reply #11 on: 21/01/2009 22:49:20 »
Thanks lightarrow
I just don't accept that about 300,000Km/s is the fastest anything can go in this vast universe.
A couple of billionKm/s maybe but 300,000 just seems way to slow.

Cheers
justaskin
Ok, but are you aware of the fact that if you are in a starship travelling at (almost exactly) that speed you can go everywhere in the universe in a few seconds?
Hi light arrow.

I thought speed was relative, making the idea of travelling at 300,000Km/s meaningless. And therefore even if you got to 300,000Km/s relative to earth light would still pass you by at C.
« Last Edit: 21/01/2009 23:00:25 by ukmicky »
 

Offline Vern

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What's the real speed limit of our universe?
« Reply #12 on: 21/01/2009 22:59:58 »
i thought speed was relative
Yes it is; and the reason why it is can be speculated to be that the final irreducible constituent of all physical reality is the electromagnetic field as H. Ziegler speculated back in 1909.
 

Offline ukmicky

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What's the real speed limit of our universe?
« Reply #13 on: 21/01/2009 23:00:57 »
i thought speed was relative
Yes it is; and the reason why it is can be speculated to be that the final irreducible constituent of all physical reality is the electromagnetic field as H. Ziegler speculated back in 1909.
Sorry i added to mine :)
 

Offline Vern

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What's the real speed limit of our universe?
« Reply #14 on: 21/01/2009 23:22:12 »
Quote from: ukmiky
Sorry i added to mine :)
Maybe why I had trouble understanding it as a response to me :) You're exactly right though; light would pass you as you measure it, at c. lightarrow is also right; I don't see a conflict between your posts.
 

Offline erickejah

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What's the real speed limit of our universe?
« Reply #15 on: 21/01/2009 23:33:33 »
to be exact c=2.99792458X108m/s.
from: my "Physics" book by "Paul E. Tippens"
how did they calculated this ??? ??? ??? ???
« Last Edit: 21/01/2009 23:35:26 by erickejah »
 

Offline ukmicky

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What's the real speed limit of our universe?
« Reply #16 on: 21/01/2009 23:37:43 »
Sorry I'm trying to understand.

We know light always travels at c no matter how fast the traveller is moving.

We also know that it would take a pulse of light 10 light years to reach us from a star 10 light years away .

Now light arrow say if we were to travel near the speed of light we could travel anywhere in the universe within a few seconds. but say if we were to travel to that planet 10 years away that its gonna take a pulse of light 10 years to get to. My three seconds would mean i would be travelling faster than the pulse of light that's gonna take 10 years to get their.

Sorry forgot about time dialation. Slaps forehead, HARD
« Last Edit: 21/01/2009 23:39:39 by ukmicky »
 

Offline justaskin

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What's the real speed limit of our universe?
« Reply #17 on: 22/01/2009 01:38:18 »
Ok, but are you aware of the fact that if you are in a starship travelling at (almost exactly) that speed you can go everywhere in the universe in a few seconds?
Quote
No!.I find that a bit hard to believe on a couple of levels.Why does light not suffer time dilation.
Quote
What does it mean?
What I was trying to say if rather confusingly was why does light not suffer time dilation eg. it takes light roughly 8 mins to get to us from the sun not a fraction of a sec or instantly or are you saying that from the light particle's point of view it does only take a second or so.
Am I understanding you correctly that if I was in a spaceship traveling at the speed of light time would stand still I could be everywhere in the universe at the same time would that not tend to suggest that if I could continue to travel at the speed of light I would have become immortal.
Even if it took me a couple of seconds to get across the universe and back I assume that billions of years of earth time would have past with all the technology advancement that that time period would imply but I would be in a rust bucket using billion year old technology.
Does that not seem a little improbable to you.
I guess I am missing something again.

Cheers
justaskin
 
 

Offline lightarrow

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What's the real speed limit of our universe?
« Reply #18 on: 22/01/2009 08:20:14 »
Ok, but are you aware of the fact that if you are in a starship travelling at (almost exactly) that speed you can go everywhere in the universe in a few seconds?
Quote
No!.I find that a bit hard to believe on a couple of levels.Why does light not suffer time dilation.
Quote
What does it mean?
What I was trying to say if rather confusingly was why does light not suffer time dilation eg. it takes light roughly 8 mins to get to us from the sun not a fraction of a sec or instantly or are you saying that from the light particle's point of view it does only take a second or so.
Am I understanding you correctly that if I was in a spaceship traveling at the speed of light time would stand still I could be everywhere in the universe at the same time would that not tend to suggest that if I could continue to travel at the speed of light I would have become immortal.
Even if it took me a couple of seconds to get across the universe and back I assume that billions of years of earth time would have past with all the technology advancement that that time period would imply but I would be in a rust bucket using billion year old technology.
Does that not seem a little improbable to you.
I guess I am missing something again.

Cheers
justaskin
 
justaskin, the reason you can go everywhere in the universe in a few seconds if you are in a starship travelling at near c (with respect to Earth) is very simple: for Lorentz contraction, every distance between planets, stars, galaxies or what you want, is contracted to almost 0 metres so, even at a finite speed you travel that distance in almost no time.
 

Offline lightarrow

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What's the real speed limit of our universe?
« Reply #19 on: 22/01/2009 08:26:53 »
Sorry I'm trying to understand.

We know light always travels at c no matter how fast the traveller is moving.

We also know that it would take a pulse of light 10 light years to reach us from a star 10 light years away .

Now light arrow say if we were to travel near the speed of light we could travel anywhere in the universe within a few seconds. but say if we were to travel to that planet 10 years away that its gonna take a pulse of light 10 years to get to. My three seconds would mean i would be travelling faster than the pulse of light that's gonna take 10 years to get their.

Sorry forgot about time dialation. Slaps forehead, HARD

Michael, please read the answer I wrote to justaskin.
Furthermore, some times ago (but of course noone remember) I explained that *in practice* light speed is infinite; in the sense of the answer to justaskin and in the sense that, if we used a more correct (in my hopinion) definition of velocity, that is an *operative* definition, we would find what is called "rapidity" in special relativity and which is exactly infinite when v = c.
The reason our definition of velocity is not so good, in my opinion, is that, at high speeds, time is *not* independent from space anylonger and so defining velocity as space/time is not so meaningful anylonger.
 

Offline justaskin

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What's the real speed limit of our universe?
« Reply #20 on: 22/01/2009 12:36:59 »

justaskin, the reason you can go everywhere in the universe in a few seconds if you are in a starship travelling at near c (with respect to Earth) is very simple: for Lorentz contraction, every distance between planets, stars, galaxies or what you want, is contracted to almost 0 metres so, even at a finite speed you travel that distance in almost no time.
lightarrow what you are saying would tend to indicate that immortality could be obtained just by traveling at the speed of light.And that Santa's trick of delivering toys to all the good boys and girls of the world over a 24 hour period would be just a walk in the park.
Also by Lorentz contraction you are suggesting that the universe could fit on the head of a pin.If not on a pin then inside of a regular sized sports stadium.
You will pardon me if I find these things to be incredible.

Cheers
justaskin
 

Offline lightarrow

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What's the real speed limit of our universe?
« Reply #21 on: 22/01/2009 14:23:16 »

justaskin, the reason you can go everywhere in the universe in a few seconds if you are in a starship travelling at near c (with respect to Earth) is very simple: for Lorentz contraction, every distance between planets, stars, galaxies or what you want, is contracted to almost 0 metres so, even at a finite speed you travel that distance in almost no time.
lightarrow what you are saying would tend to indicate that immortality could be obtained just by traveling at the speed of light.And that Santa's trick of delivering toys to all the good boys and girls of the world over a 24 hour period would be just a walk in the park.
Also by Lorentz contraction you are suggesting that the universe could fit on the head of a pin.If not on a pin then inside of a regular sized sports stadium.
You will pardon me if I find these things to be incredible.

Cheers
justaskin
When I talk about unproven things I explicitly say it's speculation. In that post I haven't done it...
Before replying with silly things, it's better if you study some relativity. I have done it a lot of time ago.
P.S.
"immortality could be obtained just by traveling at the speed of light"
Nonsense. You haven't understood what I wrote. Read it again.
« Last Edit: 22/01/2009 14:28:03 by lightarrow »
 

Offline justaskin

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What's the real speed limit of our universe?
« Reply #22 on: 23/01/2009 01:41:22 »
  You haven't understood what I wrote. Read it again.
I think you said at the speed of light time and space become 0.No?.

Cheers
justaskin
 

Offline lightarrow

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What's the real speed limit of our universe?
« Reply #23 on: 23/01/2009 09:42:49 »
  You haven't understood what I wrote. Read it again.
I think you said at the speed of light time and space become 0.No?.

Cheers
justaskin
No, I wrote that at c (measured with respect to Earth or the Sun or the fixed stars) every *distance* between planets, stars, ecc is Lorentz contacted to almost nothing so to go from Earth to the visible border of the universe you would take almost no time.

What is intended here is: if Sun-Earth distance is 149.5 millions km in the Solar system frame of reference, it would become, let's say, 1 mm in your starship frame of reference. Does it mean that "space" has become zero? No, in your reference frame space is exactly the same as before, what is changed is the value of those distances which had another value in another frame of reference. To explain better: imagine that you and your friend are travelling with 2 equal starships in opposite directions; when you pass close to the other, you measure that his starship is shorter than your, even if they had the same lenght when still with respect to each other; in the same way, he measures that your starship is shorter than his. Has "space" changed because of this? Of course no. Now imagine that there are billions of still starships and you are moving with respect to them. You measure them as all shorter with respect to your. Now call the tips and the tails of those starships "planets" or "stars" and you have understood why do you measure distances between planets or stars as shorter with respect the frame of reference where they are still.


In the same way, all of this has nothing to do with "time stops" or "becoming immortal". Your life in the starship would go as in Earth or anywhere else. Imagine to be in the middle Ages and to have a fast airplane who could get you in a few instants in every place of the planet; should people say that you have "stopped time" and "become immortal"?
I hope you have understood now...
« Last Edit: 23/01/2009 09:56:54 by lightarrow »
 

Offline justaskin

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What's the real speed limit of our universe?
« Reply #24 on: 23/01/2009 12:11:32 »
Ah ok lightarrow lets see if I understand now its from the observers frame of reference not the spaceship or its crews frame of reference.I had it back the front.Yes?.

Cheers
justaskin
 

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What's the real speed limit of our universe?
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