Opposite of the speed of light

[CraigD]

Say, guys, what topic of discussion would be the opposite of this one?

 

One that makes sense!

/forums/images/smilies/devilsign.gif

The original post’s question was a tough one, conceptually! At least we managed to make some sense of it. :)

But I disagree with saying

The opposite of the speed of light is imaginary infinity.

because ...

Qfwfq’s right:

[math]\lim_{z\rightarrow\infty}\frac{1}{\sqrt{1-(i z)^2}}= \lim_{z\rightarrow\infty}\frac{1}{\sqrt{1+z^2}}= \lim_{z\rightarrow\infty}\frac{1}{\sqrt{1-z^2}}= 0[/math]

 

I was being very liberal in my interpretation of the original question. My answer makes more sense if you recast the question with speeds high enough for dramatic relativistic effects, but low enough to avoid troublesome brushes with limits and infinity. For example, something like this:

A clock moving at about .866 c relative to an observer is observed to measure 1 second for every 2 seconds on the observer’s clock. Is there some speed at which the moving clock could move relative to the observer that would result in 2 seconds on the moving clock passing for every one on the observer’s?

This is just asking to solve [math]\sqrt{1-v^2} = 2[/math], giving [math]v = \sqrt{-3} = i \sqrt{3} \, \dot= \, i 1.732 \,\mbox{c}[/math]

 

My intention is to show that, while mathematically sensible, this sort of question results in answers with an imaginary component, which thus don’t relate in a sensible manner to anything physical. :shrug:

[snoopy]

 

My intention is to show that, while mathematically sensible, this sort of question results in answers with an imaginary component, which thus don’t relate in a sensible manner to anything physical. :)

 

 

Yeah but still a very cool answer.....:)

 

Peace

:)

[Qfwfq]

My intention is to show that, while mathematically sensible, this sort of question results in answers with an imaginary component, which thus don’t relate in a sensible manner to anything physical. :shrug:

And yet, the limit may be taken along a real-valued [imath]v[/imath] path, with the imaginary ratio corresponding to a flip between timelike and spacelike. While a negative [imath]v^2[/imath] doesn't have physical meaning in Minkowskian kinematics, a negative [imath]ds^2[/imath] does.

 

:cool:

[watcher]

Is there a place in the universe where your motion with respect to anything would zero?

 

as a thought experiment, yes.

it can be imagine by taking the perspective of light itself.

if everything is relative to c, then by its own perspective, it is not moving but sees the whole universe in motion.

 

a photon at rest of course has no mass and no time.

this implies that light exists outside spacetime.

 

so the place of zero motion is either in the non-local quantum world or it only exists as a concept in our minds.

[sanctus]

a photon at rest? What do you mean watcher?

[freeztar]

a photon at rest? What do you mean watcher?

 

I believe he meant zero rest mass. :)

 

Nonetheless, I'm confused by the statement "this implies light exists outside of spacetime". Can you elaborate on this Watcher?

[watcher]

I believe he meant zero rest mass. :)

 

Nonetheless, I'm confused by the statement "this implies light exists outside of spacetime". Can you elaborate on this Watcher?

 

the spacetime interval of photon is ZERO.

 

it has zero dimension therefore non-local, asizal

no time asymmetry. no past no future. atemporal

 

in spacetime, photon exerts a quantum of action (planck's constant, enegy x time). the building block of the universe is not an object or a thing. but a unit of action.(twisi)

 

photon is acausal. photon spins not because of forces acting upon it. but the other way around...

 

photon acts and we measure it as space, mass, time and the forces and energy that relates the three.

 

it has no opposite. but maybe has complimenatry action which is gravity. gravity sucks up spacemass back to non-locality thus completing the cycle..

 

but i have no math for this. he he he

[Symbology]

Is there a place in the universe where your motion with respect to anything would zero?

 

Well I just look to your logo for inspiration. I am am currently in zero motion relative to my seat :)

[Natural]

Is there a place in the universe where your motion with respect to anything would zero?

 

I would theorize that if you had a telescope that could see every object (i.e. mass and energy) in the universe. And you had a computer that could calculate the motions and interactions of everything for the last 14 billion years (or so). Then the computer could tell you exactly where the big bang took place and therefore would give you a reference point. And with a theoretical reference point you could see if you were moving or not and therefore could counteract your motion with respect to the "center" and be motionless.

:eek2:

[watcher]

Then the computer could tell you exactly where the big bang took place and therefore would give you a reference point. And with a theoretical reference point you could see if you were moving or not and therefore could counteract your motion with respect to the "center" and be motionless.

:steering:

 

the theoretical reference point is of course the singularity that preceeded the bigbang.

 

but singularity as an asizal and atemporal idea implies that singularity theoretically can be everywhere all at the same time or anywhere in no time at all

 

at the very least it does not require motion in a classical sense to be from one edge of the universe to the other.

 

thus singularity is motion ZERO

[InfiniteNow]

but singularity as an asizal and atemporal idea implies that singularity theoretically can be everywhere all at the same time or anywhere in no time at all

 

at the very least it does not require motion in a classical sense to be from one edge of the universe to the other.

 

thus singularity is motion ZERO

 

Actually, I think it would be more appropriate to call it that "spot" where our current mathematics break down.

 

We don't know if it's "asizal" or "atemporal," nor that it's "motion zero.'

 

To theorize beyond "this is just where our current math stops working," while fun and best done over several cocktails with friends, is to go into metaphysics and philosophy.

 

 

:):evil: :steering:

[CraigD]

I would theorize that if you had a telescope that could see every object (i.e. mass and energy) in the universe. And you had a computer that could calculate the motions and interactions of everything for the last 14 billion years (or so). Then the computer could tell you exactly where the big bang took place and therefore would give you a reference point. And with a theoretical reference point you could see if you were moving or not and therefore could counteract your motion with respect to the "center" and be motionless.

If you could find the mass and momentum of all the matter in the universe (both the visible, ordinary sort, and the “dark” sort we can’t – whatever that turns out to be), you could in principle find the center of mass of the universe and its velocity. You wouldn’t have to calculate the trajectory of every particle, “only” calculate and sum their momenta – a good thing, as such a simulation is, in principle, impossible without practically infinite precision, which might require a computer as or more massive than the universe! :steering:

 

However, what value would such a measurement and calculation have? Regardless of your location and velocity relative to the center of the universe, the laws of physics are, by best theory supported by all observation to date, the same as any other. Given how fantastically difficult it would be, and how scientifically valueless, it’s hard to imagine that anyone would ever bother to find this data.

 

Though I suspect that the location and velocity of the center of the universe is valueless knowledge, knowledge of the detailed distribution of mass in the early universe could be very valuable. Not only could it explain the formation and current state of very large scale structures (eg: clusters of clusters of galaxies), but it could tell us about the fluctuations in the universe’s quagma (a cool-sounding term I recently read) and earlier stuff before the appearance of the photons and baryons, called the Plank epoch in the Big Bang theory.

[watcher]

Actually, I think it would be more appropriate to call it that "spot" where our current mathematics break down.

 

We don't know if it's "asizal" or "atemporal," nor that it's "motion zero.'

 

To theorize beyond "this is just where our current math stops working," while fun and best done over several cocktails with friends, is to go into metaphysics and philosophy.

 

 

:cup::lol: :phones:

 

 

zero means zero and zero dimensions means no dimension.

 

einstein spacetime interval for photon is zero. it has no rest mass, no charge and no time. ideas derived from his equations.

photon is the microscale singularity and blackholes are the microscale singularity.

 

to theorize beyond is the stuff science is made of. to be hit by an apple in the head, to have a deep insight almost intuitively about light and falling body. the math can come later.

 

those who have a love affair with their maths, developed a deep attachments to their maths. they are the vanguards of the old paradigm, in a way they have their usefulness in weeding out the pseudos and crackpots (and the trail blazers?). but when a new paradigm arrives, they are usually the ones left sleeping in the coffeshops. :lol:

[Qfwfq]

I would theorize that if you had a telescope that could see every object (i.e. mass and energy) in the universe. And you had a computer that could calculate the motions and interactions of everything for the last 14 billion years (or so). Then the computer could tell you exactly where the big bang took place and therefore would give you a reference point.

 

If you could find the mass and momentum of all the matter in the universe (both the visible, ordinary sort, and the “dark” sort we can’t – whatever that turns out to be), you could in principle find the center of mass of the universe and its velocity.

:phones:

 

Not according to the standard model of cosmology. It does not envision there being such a centre of mass in the spatial submanifold for a given CST, which is described as the boundary of a hypersphere; the singularity is in the past and doesn't correspond to any point of the present in particular.

[InfiniteNow]

zero means zero and zero dimensions means no dimension.

 

einstein spacetime interval for photon is zero. it has no rest mass, no charge and no time. ideas derived from his equations.

photon is the microscale singularity and blackholes are the microscale singularity.

 

to theorize beyond is the stuff science is made of. to be hit by an apple in the head, to have a deep insight almost intuitively about light and falling body. the math can come later.

 

those who have a love affair with their maths, developed a deep attachments to their maths. they are the vanguards of the old paradigm, in a way they have their usefulness in weeding out the pseudos and crackpots (and the trail blazers?). but when a new paradigm arrives, they are usually the ones left sleeping in the coffeshops. :lol:

 

You've done nothing to disprove my point, and simply repeating yourself adds zero validitity to yours.

[CraigD]

zero means zero and zero dimensions means no dimension.

 

einstein spacetime interval for photon is zero. it has no rest mass, no charge and no time. ideas derived from his equations.

photon is the microscale singularity and blackholes are the microscale singularity.

Though I’m having some trouble following your meaning, watcher, I think you’re describing the “what if you were ‘riding a photon’” thought experiment, which goes something like this:

 

Given:

Alice and Bob are near and still with respect to one another. Both of their watches read 00 h:00 m:00 s

Alice catches a passing photon, accelerating instantly to c

At 00:00:01 on her watch, Alice lets go of the photon and, seizes a conveniently placed arrestor cable to come to instantly come to rest relative to Bob.

Questions:

How far apart are they?

What does Bob’s watch read?

Or

 

Given:

Alice and Bob are near and still with respect to one another. Both of their watches read 00 h:00 m:00 s

Alice catches a passing photon, accelerating instantly to c

At 00:00:01 on his watch, Bob observes Alice coming to rest 1 light-second (299792458 m) away.

Question:

What does Alice’s watch read?

The first questions have answers prone to stir controversy among math purists. The last has a simple, but paradoxical, answer.

 

:lol: Watcher, how would you answer these three questions?

 

(Some lengthier discussion of this was had in the thread 6191)

those who have a love affair with their maths, developed a deep attachments to their maths. they are the vanguards of the old paradigm, in a way they have their usefulness in weeding out the pseudos and crackpots (and the trail blazers?). but when a new paradigm arrives, they are usually the ones left sleeping in the coffeshops.

Sleeping in coffeshops – mmm, I miss that! :evil:

 

I think you mischaracterize the imaginations of those with love affairs with math. I’d describe myself thus, but have rarely been faulted for a lack of wildness – see “A Math Student’s Campfire Tale About Time” for an example.

[Natural]

I think a lot of the problem with the "spot" of the big bang theory is that modern physics assumes that space and time were created during the BB and therefore the math breaks down. But what if space and time already existed (unattached from the universe) and the BB occurred "in" space and time. (maybe more than once):lol:

Also I have a theory (more like an intuition) that there is a stopping point on the quantum scale at which matter can no longer collapse. (somewhere smaller than quagma) We just don't know what to call the "particles" that would make up such a point. Or the ability to measure their dimensions.

:lol:

(you can't pick up an atom with tweezers...)

:P:ideamaybenot: