Variable Light Speed

Post by **Freakzilla** » 14 May 2008 06:28

Last night I watched a show on The Science Channel about the theories of João Magueijo, a Portuguese Cosmologist.

He is a pioneer of the varying speed of light (VSL) theory of cosmology, which proposes that the speed of light was much higher in the early universe, of 60 orders of magnitude faster than its present value. It is presented as an alternative to the more mainstream theory of cosmic inflation. The model was first proposed by John Moffat, a Canadian scientist, in 1992.

Magueijo discusses his personal struggles pursuing VSL in his 2003 book, Faster Than The Speed of Light, The Story of a Scientific Speculation.

Magueijo is the host of the Science Channel series, João Magueijo's Big Bang, which premiered on May 13, 2008.

http://en.wikipedia.org/wiki/Jo%C3%A3o_Magueijo

The variable speed of light (VSL) concept states that the speed of light in vacuum, usually denoted by c, may not be constant, for some reason. In most situations in condensed matter physics when light is traveling through a medium, it effectively has a slower speed. Virtual photons in some calculations in quantum field theory may also travel at a different speed for short distances; however, this doesn't imply that anything can travel faster than light. While it is usually thought that no meaning can be ascribed to a dimensional quantity such as the speed of light varying in time (as opposed to a dimensionless number such as the fine structure constant), in some controversial theories in cosmology, the speed of light also varies by changing the postulates of special relativity. A fundamental change to relativity is needed if c is changing because relativity shows that space and time are equivalent.

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

Anybody buying this theory?

orald · Post by **orald** » 14 May 2008 06:43

FZ wrote:Anybody buying this theory?

I'll buy that for dollar!

Yea, umm, when I decide to get a theoretical physics degree or two I'll let you know.

Fantômas · Post by **Fantômas** » 14 May 2008 07:54

Well, I think light could travel faster or slower according to what medium the light is traversing. If light is bent because of Gravity, then light could be affected by other factors. I wonder if the speed is changed by the absorption of the photons, or whatever light is made of, when light encounters another medium. Inversely, does the speed of light increases when passing thru a part of space which has little matter?

Who knows?

Serkanner · Post by **Serkanner** » 14 May 2008 10:22

I have always wondered if the speed of light is instantaneously reached or does it need to accelerate just like other "objects"?

Post by **Freakzilla** » 14 May 2008 10:52

What is makes me wonder about, if the speed has varied over time, is the observation that galaxies further away from us are moving away from us faster than ones that are closer to us.

The light from those galaxies on the edge of the observable universe is billions of years old.

If this theory were true, it would imply that the distance calculations were off.

As well as ALL other cosmic distances.

orald · Post by **orald** » 14 May 2008 10:55

Serkanner wrote:I have always wondered if the speed of light is instantaneously reached or does it need to accelerate just like other "objects"?

From what little I understand, I thought light particles, i.e photons(right?) "escape" from those lumineous objects at said light speed, so no acceleration is going on.

I'm not sure why exactly they escape though...is it like knocked out particles in radioactive processes, like in atomic bombs?

Physics was never my thing, I prefer to play around with(for the moment) living stuff.

GamePlayer · Post by **GamePlayer** » 14 May 2008 12:30

Sounds like another of these "Would be great if it were true, but no one can prove let alone test the theory as yet, so we really don't have anything to say at all"

Perhaps there's more to it, but I'm not really seeing it so far.

A Thing of Eternity · Post by **A Thing of Eternity** » 14 May 2008 13:17

Maybe. Don't have my PHD, so whatever I say is just based on what other people have told me, who may be wrong. I can't say it's impossible, I can say that for now I have to go with the majority due to my inexperience.

Serkanner · Post by **Serkanner** » 14 May 2008 13:33

orald wrote:
Serkanner wrote:I have always wondered if the speed of light is instantaneously reached or does it need to accelerate just like other "objects"?

I'm not sure why exactly they escape though...i

They run away so they don't have to reflect back from the hideous one ... also know as ... KJA!

Mandy · Post by **Mandy** » 14 May 2008 13:35

I watched the show last night too.. it was very interesting but I hated the graphics, or editing, whatever you'd call it.

orald · Post by **orald** » 14 May 2008 16:39

Mandy wrote:I watched the show last night too.. it was very interesting but I hated the graphics, or editing, whatever you'd call it.

Jeez, you damn graphics whore!

Back in my day when we watched TV there was no picture at all, only sound!

A Thing of Eternity · Post by **A Thing of Eternity** » 14 May 2008 16:58

orald wrote:
Mandy wrote:I watched the show last night too.. it was very interesting but I hated the graphics, or editing, whatever you'd call it.
Jeez, you damn graphics whore!

Back in my day when we watched TV there was no picture at all, only sound!

And you walked to school, 20 miles... uphill both ways?

Post by **Freakzilla** » 14 May 2008 17:19

A Thing of Eternity wrote:
orald wrote:
Mandy wrote:I watched the show last night too.. it was very interesting but I hated the graphics, or editing, whatever you'd call it.
Jeez, you damn graphics whore!

Back in my day when we watched TV there was no picture at all, only sound!
And you walked to school, 20 miles... uphill both ways?

...in the snow.

SandChigger · Post by **SandChigger** » 14 May 2008 18:24

fantomas wrote:Well, I think light could travel faster or slower according to what medium the light is traversing. If light is bent because of Gravity, then light could be affected by other factors. I wonder if the speed is changed by the absorption of the photons, or whatever light is made of, when light encounters another medium. Inversely, does the speed of light increases when passing thru a part of space which has little matter?

Who knows?

Well, you certainly don't.

Light itself is not "bent by Gravity"; the spacetime it is travelling through is. Yes, light is made of photons, and yes, when light passes through anything other than a vacuum (=a part of space with little or no matter in it), the speed of the photons is affected by the atoms of the medium. (They absorb and reemit them, roughly speaking.) The denser the material, the longer the photon takes to penetrate it, if at all; I've read that it takes a million years for a photon to travel from the core of the sun to its surface. Whether that's true or not...

Who knows.

orald · Post by **orald** » 14 May 2008 18:51

You try and tell the kids these days...they wouldn't believe you!

Mandy · Post by **Mandy** » 14 May 2008 20:20

orald wrote:
Mandy wrote:I watched the show last night too.. it was very interesting but I hated the graphics, or editing, whatever you'd call it.
Jeez, you damn graphics whore!

Back in my day when we watched TV there was no picture at all, only sound!

Well if you saw the program you'd know what I'm talking about. It actually had too much fancy graphics when the subject was interesting enough on it's own. I've noticed that a few of these theoretical scientist types have shows with lots of flashy distracting crap.

He actually explained his ideas very well.. my memory is shit though so I don't remember enough about it to say what I think of his VLS theory.

HoosierDaddy · Post by **HoosierDaddy** » 14 May 2008 23:35

This subject is interesting, and I hope to see the TV show. Based on what the wiki implies, C is pretty much constant since the big bang, assuming physics as we know it.

Could somebody artificially create conditions that are similar to "big bang" space/time? If so, then we are looking at something really interesting. Maybe this is "fold space", of a "warp field".

:crackpipe

Post by **Omphalos** » 14 May 2008 23:59

HoosierDaddy wrote:This subject is interesting, and I hope to see the TV show. Based on what the wiki implies, C is pretty much constant since the big bang, assuming physics as we know it.

Could somebody artificially create conditions that are similar to "big bang" space/time? If so, then we are looking at something really interesting. Maybe this is "fold space", of a "warp field".

:crackpipe

How about with a quantum black hole? This is way out of my area of knowledge, but what about that?

Phaedrus: Have at me, sir!

loremaster · Post by **loremaster** » 15 May 2008 02:23

Serk - Orald is right, waves and so on can be emitted at light speed (in a vaccuum). However I dont think its actually possible to accelerate up to lightspeed, no object with substantial mass will be able to accelerate to lightspeed.
But there are methods of moving the "Space" which includes an object, at lightspeed. (draw an outline 1metre bigger than the spaceship, and take all the "space" between that outline, which happens to include the spaceship.)

They "Escape" as orald put it because electrons which orbit an atom get "Excited" by energy and jump up a bit, when they fall back down, they release the energy they gained (when they got excited) as a photon.

And about VSL - It's already been "Shown" (as much as anything which occured billions of years ago can be) that other universal constants have changed since then and now. Both the strong and weak nuclear forces, as well as gravity, were considered possibly weaker or stronger in the early universe.

Infact, universal "constants" not being constant is one idea in multiverse theory, and also goes a long way to explain WHY our constants are what they are (Universes where the constants may have been substantially different from ours would not last long).

I'm sure i`ve heard before also that because of these constants speed of light might be slightly slower now than it was. If i remember correctly (not having seen this guys program), the point is that he thinks it could have been drastically different from what it is now.

And I think one of the most likely ways we might be able to "fold space" would be to "Pair" black holes with white ones. Technically, constantly traversing this loop would take you back in time....... but only to the point at which the black hole and the white hole were paired.

Phaedrus · Post by **Phaedrus** » 15 May 2008 02:47

HoosierDaddy wrote:This subject is interesting, and I hope to see the TV show. Based on what the wiki implies, C is pretty much constant since the big bang, assuming physics as we know it.

Could somebody artificially create conditions that are similar to "big bang" space/time? If so, then we are looking at something really interesting. Maybe this is "fold space", of a "warp field".

I've heard if you collide really, really, small particles at really, really high velocities, you'll simulate some of the conditions of the big bang. We came up with these theories somehow, you know.

How about with a quantum black hole? This is way out of my area of knowledge, but what about that?

Phaedrus: Have at me, sir!

I would, but first I would have to try to figure out what "quantum black hole" implies. As far as I can tell...nothing.

As for the variable c thing...I'm tired of people coming up with random theories to explain phenomena that MIGHT exist. Wait until we detect the phenomena before you try to explain it, kthxbai. Ideas like this aren't even bad science, they're just not science.

Speculation isn't necessarily a bad thing, but you end up with a bunch of people who refuse to accept that there is no aether out there.

(BTW, they've delayed firing the LHC another two months, so we get to wait even longer to see if physics has any hope.)

Serkanner · Post by **Serkanner** » 15 May 2008 03:27

loremaster wrote:Serk - Orald is right, waves and so on can be emitted at light speed (in a vaccuum). However I dont think its actually possible to accelerate up to lightspeed, no object with substantial mass will be able to accelerate to lightspeed.
But there are methods of moving the "Space" which includes an object, at lightspeed. (draw an outline 1metre bigger than the spaceship, and take all the "space" between that outline, which happens to include the spaceship.)

They "Escape" as orald put it because electrons which orbit an atom get "Excited" by energy and jump up a bit, when they fall back down, they release the energy they gained (when they got excited) as a photon.

Thank you very much. I am now more knowledgeable then yesterday

orald · Post by **orald** » 15 May 2008 06:48

Phaedrus, what the LHC?

The new particle accellerator thingy that was mentioned in another thread?

And what's a white hole? I'm assuming it, being the "opposite", spews material out?

loremaster · Post by **loremaster** » 15 May 2008 08:07

Orald - A White hole is something which is theorised to exist (I dont know if anyone has actually seen them).

It is similar to a black hole, at least from the outside. Black holes have what are called "Event Horizons". An event horizon might be thought of as a ring, somewhere, around the centre of a black hole. Anything which is occuring within this ring does not affect anything outside. That is the definition of an event horizon.

Black holes, therefore, because of the way the light cone points (I dont understand this bit), has a middle (a centre) which is inescapable, a "White hole" would have no true centre and could not be reached.

- But this all lies over the event horizons and wont affect us anyway, its just what would happen if you ever went over (ie sufficiently close to) one. But you'd die long before that due to the awesome forces involved.

The theory goes that, if you could set up an almost Yin-Yang relationship, something which "Fell" into a black hole could be ejected at the white hole..... assuming you could get close to the black hole without being destroyed, and get it out again from the "white" one (which would still look black to us) without it being destroyed.

Also:

Phaedrus Wrote:

As for the variable c thing...I'm tired of people coming up with random theories to explain phenomena that MIGHT exist. Wait until we detect the phenomena before you try to explain it, kthxbai. Ideas like this aren't even bad science, they're just not science.

It's said by some that there's speculation, wild speculation.... and then cosmology.

Fantômas · Post by **Fantômas** » 15 May 2008 09:09

SandChigger wrote:
fantomas wrote:Well, I think light could travel faster or slower according to what medium the light is traversing. If light is bent because of Gravity, then light could be affected by other factors. I wonder if the speed is changed by the absorption of the photons, or whatever light is made of, when light encounters another medium. Inversely, does the speed of light increases when passing thru a part of space which has little matter?

Who knows?
Well, you certainly don't.

Light itself is not "bent by Gravity"; the spacetime it is travelling through is. Yes, light is made of photons, and yes, when light passes through anything other than a vacuum (=a part of space with little or no matter in it), the speed of the photons is affected by the atoms of the medium. (They absorb and reemit them, roughly speaking.) The denser the material, the longer the photon takes to penetrate it, if at all; I've read that it takes a million years for a photon to travel from the core of the sun to its surface. Whether that's true or not...

Who knows.

Post by **Omphalos** » 15 May 2008 12:28

A quantum black hole is a minature one. A dust mote that collapsed on itself so much that it ruptured a tiny amount of space. One step beyond neutronium, but just a little bit.