light speed

[Xittenn]

Wouldn't a Tachyon, technically speaking, have been created by the 'Big Crunch' and be traveling backwards through time!

[Airbrush]

Martin, those are excellent points you make and I did read that Big Bang misconceptions before, more than once, but the term "Big Bang" is a sad misnomer. They should call it the "Great Expansion" which would be more descriptive. My mind is stubbornly clinging to the image of a Bang in empty space.

 

Could tachyons, or something like them, have something to do with cosmic inflation?

[Martin]

... but the term "Big Bang" is a sad misnomer. They should call it the "Great Expansion"...

 

Could tachyons, or something like them, have something to do with cosmic inflation?

 

Absolutely right about the misnomer. The name was given antagonistically by Fred Hoyle who didn't like the theory and had no interest in representing it accurately. (He favored an alternative steadystate model.)

 

I gather that a tachyon is a field whose mass is an imaginary number (like the square root of -1 is an imaginary number.) Usual matter masses are positive real numbers, so this is already pretty exotic. There is no experimental evidence for the existence of tachyons.

 

Airbrush, I really should not be talking on this subject. Don't know enough. Here's what I gather from the Wikipedia article:

"Since a tachyon's squared mass is negative, it formally has an imaginary mass. This is a special case of the general rule, where unstable massive particles are formally described as having a complex mass, with the real part being their mass in usual sense, and the imaginary part being the decay rate in natural units[4].

 

However, in quantum field theory, a particle (a "one-particle state") is roughly defined as a state which is constant over time, i.e. an eigenvalue of the Hamiltonian. An unstable particle is a state which is only approximately constant over time; However, it exists long enough to be measured. This means that if it is formally described as having a complex mass, then the real part of the mass must be greater than its imaginary part. If both parts are of the same magnitude, this is considered a resonance appearing in a scattering process rather than particle, since it does not exist long enough to be measured independently of the scattering process. In the case of a tachyon, the imaginary part of the mass is infinitely larger than the real part, and hence no concept of a particle can be attributed to it.

It is important to stress that even for tachyonic quantum fields, the field operators at spacelike separated points still commute (or anticommute), thus preserving causality. Therefore information never moves faster than light."

http://en.wikipedia.org/wiki/Tachyon

 

Cosmic inflation may not have happened. People are still working on alternative ideas of how the remarkable degree of flatness and temperature uniformity that we observe might have come about. Inflation is just the earliest conjectured scenario that offered an explanation. Personally i have no opinion. I neither believe nor disbelieve that inflation happened. I kind of suspect that maybe it did, but don't assume it.

 

But just for argument's sake let's assume an inflation episode occurred--the mechanism usually imagined is a scalar field. Sometimes this imagined field is called an "inflaton". Nothing that has ever been observed would serve the purpose. In other words the proposed physical mechanisms of inflation are total fantasy so far---they are exotic physics, resembling tachyon fields in regard.

 

The upshot is that you are right in the sense that if a field could have existed very briefly in the early universe with mass that was an imaginary number (the tachyon property) it might have served as an inflaton field and driven inflation, then an eyeblink later decayed into more ordinary types of matter.

 

Aaargh. I knew I shouldn't have tried to respond to this. But I won't erase it.

Edited March 19, 2009 by Martin

[XxFar0wxX]

isn't the speed of light slowly slowing down ?

In 1738: 303,320 +/- 310 km/second

In 1861: 300,050 +/- 60 km/second

In 1877: 299,921 +/- 13 km/second

In 2004: 299,792 km/second

 

when is the next time they will measure the speed of light again?

 

I also watched the Universe on the science channel and they said that the big bang when it first stated to explode had to be faster then the speed of light as it is now cuz the Galaxies that are farther away are more developed (or less i forget ) then the one that are close

[insane_alien]

light isn't slowing down, our measurements are getting much more precise. the errors in the early experiments were much greater than what you have posted by several orders of magnitude.

[Airbrush]

The upshot is that you are right in the sense that if a field could have existed very briefly in the early universe with mass that was an imaginary number (the tachyon property) it might have served as an inflaton field and driven inflation, then an eyeblink later decayed into more ordinary types of matter.

 

Aaargh. I knew I shouldn't have tried to respond to this. But I won't erase it.

 

Please leave this here. What a mind-twister. I need to read that a few times.

Edited March 19, 2009 by Airbrush

[XxFar0wxX]

light isn't slowing down, our measurements are getting much more precise. the errors in the early experiments were much greater than what you have posted by several orders of magnitude.

 

True because space expanding wouldn't effect light in anyways

~thanks

[moth]

True because space expanding wouldn't effect light in anyways

~thanks

 

actually, as photons travel through expanding space, their wavelength increases (and frequency decreases) because they get stretched.

[cameron marical]

what about electrons, when moving, i understand that they seem "jump" in and out of space. could it be that they accelerate temporarily past the speed of light making it unseen for a second, then slow down again. i wonder what would make them do that. maybe they have something orbiting them themselves.

[Janus]

what about electrons, when moving, i understand that they seem "jump" in and out of space. could it be that they accelerate temporarily past the speed of light making it unseen for a second, then slow down again. i wonder what would make them do that. maybe they have something orbiting them themselves.

 

 

If you are thinking about electrons "jumping" to different orbitals of an atom, there is no actual physical movement involved. The orbitals are "probability clouds" They are the regions where you are most likely to, but not necessarily will, find an electron of a given energy level. So, when an electron "jumps" to a new orbital, what happens is that the probability that you would find the electron at a given position changes, not its actual position.

[lakmilis]

Martin.. I in some of my early metaphysical models (nevermind what they were), had postulates that 'tachyons' were not particles but a field. Anyway.. nevermind that.. I saw someone say run off and you went on about the misview of the big bang. sure.. but to their defence.. the universe is expanding faster than the visible universe, i.e. the very first photons. *If* tachyons would be particles, sure.. I agree with you they can be floating past us etc, no need to be ONLY ahead of the visible universe.. but it would also be tru to say.. that they indeed would be constituing or residing as well in the non visible part of the universe.. aslight has not reached there yet.

 

Someone also said.. ye but what if we just can't observe them by nature.. ah yes.. skepticlance or so... well if absolutely no interaction.. why not? sure.. and why not pink elephants flying in yellow jaguars under bork , twelve degrees skewed towards dangdang?

 

It is of no relevance, hence sure... why not....