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A minimum speed?

by FZ+
Tags: minimum, speed
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FZ+
#1
Apr10-03, 02:03 PM
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I wonder, since c presents a maximum speed limit to the universe, is it plausible for there to be a theoretical minimum (and non-zero) speed limit too?
Such a limit would certainly have interesting implications...
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BoulderHead
#2
Apr10-03, 02:44 PM
P: n/a
This seems vaguely familiar to me though I don't have any serious knowledge of physics. I was thinking that if the electrons themselves slowed down to nil that the gig we know as the universe would be up.

[edit]
Ok, I just saw the part about non-zero. Maybe someone would like to explain the details of my post for me?
climbhi
#3
Apr10-03, 03:49 PM
P: n/a
Well correct me if I'm wrong but.. Heisenberg: ΔxΔp = h/4π so if Δp→0 then Δx doesn't make sense anymore, so there must be some minimum jitternig speeds to prevent this. But I might be wrong...

FZ+
#4
Apr10-03, 06:30 PM
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P: 1,954
A minimum speed?

Uh... by non zero I meant no annoying replies saying that you can't get a speed less than zero and stuff like that. I am wondering if there is a minimum speed above zero, or whether there is a theoretical reason why zero-speed, relative to anything, is impossible.
Brad_Ad23
#5
Apr10-03, 06:57 PM
P: 499
You would be correct climbhi.

Quantum claustrophobia is what it is referred to.
BoulderHead
#6
Apr10-03, 07:06 PM
P: n/a
Originally posted by FZ+
Uh... by non zero I meant no annoying replies saying that you can't get a speed less than zero and stuff like that. I am wondering if there is a minimum speed above zero, or whether there is a theoretical reason why zero-speed, relative to anything, is impossible.
I wish I could remember what someone who thought he knew told me about zero speed. I don't know if everything just ceases to be, implodes, or what the heck. I think the gist of it was that movement was essential. Thatís really all I can throw into the arena.
Could it be something like absolute zero where you can't actually get there except through extrapolation?
climbhi
#7
Apr10-03, 07:37 PM
P: n/a
Originally posted by FZ+
Uh... by non zero I meant no annoying replies saying that you can't get a speed less than zero and stuff like that. I am wondering if there is a minimum speed above zero, or whether there is a theoretical reason why zero-speed, relative to anything, is impossible.
Is this in reference to my post showing you couldn't have zero speed with Heisenberg? If so sorry, I thought it was valid (apparantely Brad does too...) Am I mistaking what you're refering to?
Michael F. Dmitriyev
#8
Apr10-03, 08:22 PM
P: 348
Originally posted by FZ+
I wonder, since c presents a maximum speed limit to the universe, is it plausible for there to be a theoretical minimum (and non-zero) speed limit too?
Such a limit would certainly have interesting implications...
It is possible to speak of minimum speed relatively a zero point only. That you offer to take as zero point?
eNtRopY
#9
Apr10-03, 09:29 PM
P: n/a
Originally posted by climbhi
Well correct me if I'm wrong but.. Heisenberg: ΔxΔp = h/4π so if Δp→0 then Δx doesn't make sense anymore, so there must be some minimum jitternig speeds to prevent this. But I might be wrong...
Well, you're not wrong per se... but I believe that the &Delta;p you have shown refers to the variance (or might say the standard deviation... the square root of the variance) of the expectation <p> (ie <p2> - <p>2). So, I believe the correct way to interpret this result is to say that the velocity of an object is centered around a certain value with an uncertainty given by this deviation. In that sense, the probability of measuring the velocity of a rest object at exactly zero is more probable than measuring it at any other value... but this probability is still zero.

Actually in solid state physics, people are often concerned with calculating phonon modes in low dimensional systems.

Side Bar: For those of you not in the know... a phonon mode in an array of atoms is analogous to the vibration found in a matrix of balls with each ball attached to its nearest neighbors by springs.

There is a lowest energy value a system can have... due to your reasoning. It is refered to as the zero point energy.

eNtRopY
ObsessiveMathsFreak
#10
Apr11-03, 07:51 AM
P: 406
1/c

seriously though...

I don't think such a speed could be said to exist.

remember all objects must be at rest with respect to themselves. All other speeds are relative. So zero speed is possible.
elas
#11
Apr11-03, 09:40 AM
P: n/a
All speeds in space are relative therefore it is impossible to determine either a maximum or minimum speed except in relation to an object whose true speed is unknown.
eNtRopY
#12
Apr11-03, 12:29 PM
P: n/a
Originally posted by eNtRopY
Well, you're not wrong per se... but I believe that the &Delta;p you have shown refers to the variance (or might say the standard deviation... the square root of the variance) of the expectation <p> (ie <p2> - <p>2). So, I believe the correct way to interpret this result is to say that the velocity of an object is centered around a certain value with an uncertainty given by this deviation. In that sense, the probability of measuring the velocity of a rest object at exactly zero is more probable than measuring it at any other value... but this probability is still zero.

Actually in solid state physics, people are often concerned with calculating phonon modes in low dimensional systems.

Side Bar: For those of you not in the know... a phonon mode in an array of atoms is analogous to the vibration found in a matrix of balls with each ball attached to its nearest neighbors by springs.

There is a lowest energy value a system can have... due to your reasoning. It is refered to as the zero point energy.

eNtRopY
I would like to further elaborate and say that you have a zero probability of finding any object at any exact speed due to the argument originally posted by climbhi.

eNtRopY
climbhi
#13
Apr11-03, 07:19 PM
P: n/a
Originally posted by ObsessiveMathsFreak
1/c

seriously though...

I don't think such a speed could be said to exist.

remember all objects must be at rest with respect to themselves. All other speeds are relative. So zero speed is possible.
I'm pretty sure that 1/c is not it if there was a lowest speed. Afterall think of how fast your toe nails grow, prolly pretty close to 1/c
Funkee
#14
Apr11-03, 10:27 PM
P: n/a
But assume that light, originating from the 5th dimension offers our only reference point to absolute motion. Being that we have mass when we are standing still, we must all be moving together at some rate. But due to entropy (no pun intended)... the chaos of the motion defines no absolute direction of motion. As time goes by, it will only become more chaotic, making reaching minimum speed the more difficult, if we can even slow ourselves down somehow.
Michael F. Dmitriyev
#15
Apr12-03, 03:33 AM
P: 348
The constant exist. The Constant this NOT CHANGEABLE VALUE. Any measured comparatively constant a value will be absolute, not relative. Exactly a constant is a zero point. This obviously. It is difficult to explaine the reason people prefer to stand on head...
Certainly, I am saying about the speed of light "c".
STAii
#16
Apr12-03, 04:30 AM
STAii's Avatar
P: 353
Very interesting.
I personally do not see any reason for having a minimum speed, so i believe the minimum speed of any object will be 0.
Some quotes ...
elas
All speeds in space are relative therefore it is impossible to determine either a maximum or minimum speed except in relation to an object whose true speed is unknown.
Well, although speeds are relative, we find a maximum (relative) speed, which is (c), but this is not a good enough reason to think there is a minimum speed too .
climbhi
Well correct me if I'm wrong but.. Heisenberg: [del]x[del]p = h/4[pi] so if [del]p->0 then ÉĘx doesn't make sense anymore, so there must be some minimum jitternig speeds to prevent this. But I might be wrong...
I don't go with you in this point at all (i see Entropy was right in this point).
If [del]p->0 it does not mean that p->0, (therefore it does not mean that v->0) so the HUP will be useless to find any good result in this conversation.
wimms
#17
Apr23-03, 12:58 PM
P: 473
Speed is distance/time. Minimum speed is planck length/planck time. Hmm, isn't it like "c"?

I'd add another view. What is speed? motion. What is motion? Interaction. So, zero speed is zero interaction. Now the big one - what does it mean to exist? If two particles never interact, do they exist relative to each other? Isn't stopping to complete standstill equivalent ceasing to exist? Virtual vacuum comes to mind.
FZ+
#18
Apr23-03, 01:39 PM
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P: 1,954
wimms: by that argument, there can be no minimum speed, since as t decreases, the speed increases.


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