Questions about light

Jun 10, 2022
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Hello. I'm not sure if this is the right place for this question, or even if Space.com is the right venue, but as they say, you miss every shot you don't take, so here goes. By the way, this is for a story that I'm writing.

1. Is it possible to have bright light without heat? I'm talking light bright enough to make you look away.

2. Could light (theoretically) carry a virus; even oversaturation of vitamin D? I need light to make someone sick, if possible.

3. Let's assume a being of pure light existed. Could this being (essentially light) be infected with something from us - say a cold?

4. This one is a SF stretch for sure (as they all are), could light be made to move faster than light?

Please keep in mind that I'm assuming some writers privilege on the science here.

Thanx for any input.
 
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May 14, 2021
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Agree with Cat, heat is light, or photons of infrared, if there are no photons in the infrared portion of the spectrum, no heat is transmitted. However, if there is enough light, of let’s say, blue light, and it is absorbed by a surface, it can be transformed into heat by virtue of the energy absorbed, if less is re-emitted or removed by conduction by the material.

No, light, is photons of energy, and cannot carry a virus.

A cold, or any other disease, consists of bodies of a virus, bacteria, or multicellular life. Basically, a photon of light cannot carry anything, like any kind of matter with it.

Light, by definition, moves at the speed of light, no more, no less, hence the term.

Tachyon is a hypothetical particle, coined by Gerald Feinberg in 1967 in a paper, which travels faster than light. Current physics says these don’t exist. But, some science fiction sometimes uses tachyons to perform a function which would be otherwise impossible, like Star Trek’s tachyon field. Artisitic license and sci-fi technobabble.
 

Catastrophe

"There never was a good war, or a bad peace."
Creatures made of light, if there were such things, could not carry disease. However, they could be killed by substances which absorbed their particular wave length. At least, that is the best I can think of a highly imaginary and hypothetical idea.

Cat :)
 
Tachyon is a hypothetical particle, coined by Gerald Feinberg in 1967 in a paper, which travels faster than light. Current physics says these don’t exist. But, some science fiction sometimes uses tachyons to perform a function which would be otherwise impossible, like Star Trek’s tachyon field. Artisitic license and sci-fi technobabble.
Adding a little more to the story, IIRC, tachyons have never been found but, in theory, they could exist.
 
Jun 10, 2022
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Great replies - I'm copying all this and printing it to help me - your efforst are not wasted!

So a ship made of light could, in an SF fantasy world, use something like tachyons to accelerate faster than light?? hmmm
 
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Jun 10, 2022
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Creatures made of light, if there were such things, could not carry disease. However, they could be killed by substances which absorbed their particular wave length. At least, that is the best I can think of a highly imaginary and hypothetical idea.
I like this - a lot.

Could you expound? In a hypothetical SF fantasy world, could humans unintentionally have something that could accomplish this, but delayed?

I know this is a lot to ask, but since you are helping, I thought I might press my luck
 
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Catastrophe

"There never was a good war, or a bad peace."
Great replies - I'm copying all this and printing it to help me - your efforst are not wasted!

So a ship made of light could, in an SF fantasy world, use something like tachyons to accelerate faster than light?? hmmm
!So a ship made of light could, in an SF fantasy world, use something like tachyons to accelerate faster than light?? hmmm !

No. Tachyons are pure imagination at present. Even so, they are imagined to exist FTL only, and they cannot come sub light speed. At least, that is my understanding. I am open to correction.

Cat :)
 
Nov 19, 2021
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I read this joke somewhere but didn't give it much thought.
"Time travel" is forbidden only going into the past. We all can travel into the future, as far as we want as fast as we want, just depending on how much fuel we have for acceleration.
The postulated tachyon, travelling faster than light in a vacuum, would necessarily have negative mass and would travel backwards in time.
In the joke I suppose the tachyon travelled back into the past, ordered the drink then went into the future and walked into the bar to drink it.
 
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Catastrophe

"There never was a good war, or a bad peace."
I do not see this prohibition on travelling into the past as a problem. The past is beyond the point where we can interact with it. OK, there are a few practical miniscular trivialities to sort out, but, obviously when you think about it, these time travellers (us) are what we call ghosts.

Boys, tut tut, come on now. These trivialities are not jokes. They went out with 5 year olds in the (19)30s. "Belie you intelligence comes to mind. Still, after a bottle of whiskey . . . . . . well, let's get back on topic ;)

Light governs our lives. Especially those of physicists. As I have already mentioned elsewhere, light can be introduced into a 4-dimensional as ct, with the dimensions (metres/second) x second, so that it offers 4 'space' dimensions. This has the consequence that we are all travelling forwards in the time dimension at the speed of light. Interesting stuff for fiction writers.


Cat :)


(
 
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Regarding the joke, I was trying to think about how us time-forward travelers would perceive a tachyon walking into a bar and getting a drink and walking out. Silly, but maybe instructive.

It seems to me that I need to start with the Tachyon and bartender being in the same place at the same time to interact, which is that "What'll you have" interaction, but could be a "ping" on a tachyon detector.

So, "before" that time in our time line, we should have seen the backward time-traveling tachyon "leaving the bar" in his time direction, which would look to us forward time-traveling folks like the tachyon was coming into the bar walking backwards. And, after we see the tachyon interact with the bar tender, we should see it going out of the bar, backwards, which is, to the tachyon, walking in frontwards.

So, from our standpoint, what is our take on cause and effect? Was that "backward tachyon" offended by the bartender? (Bias pun intended.)

It would start sounding too gross to go into the details about how a tachyon drinking a glass of beer would look in reverse. Suffice it to say that it must involve some things that would look like violations of the principle that entropy always increases. For instance, would the beer have come out of the glass and back into the bottle in the tachyon's frame of reference or ours? And that bottle cap would have to jump of the bar surface, land squarely on the bottle mouth and be somehow crimped tight by the bottle "opener" in one time-frame of reference or the other.

Too confusing! Maybe tachyons shouldn't drink. They seem to make me fee drunk.
 
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Catastrophe

"There never was a good war, or a bad peace."
OP opened as follows:

Hello. I'm not sure if this is the right place for this question, or even if Space.com is the right venue, but as they say, you miss every shot you don't take, so here goes. By the way, this is for a story that I'm writing.
I hope that Dave is not going to incorporate inebriated tachyons into his book, based on the apparent science of space.com forum. ;)

Cat :) :) :)
 

Catastrophe

"There never was a good war, or a bad peace."
Hmmmm. Doesn't this action at a distance thing only produce entanglement when the two parties exceed speed of light communication - an assumption which then gets extended far, far away, to 'infinity' by the theorists?

In good quantum theory style, is this then real to them, but not to anyone not participating in the split?

Cat :)
 
I don't know that "entanglement" has actually been shown to be or require separated actions to be occurring faster than light could have carried a message between those locations. But, I may be wrong about that. I do think you are correct that it is assumed that communication does not happen in any way we can detect, and is instantaneous (whatever that means to things in 2 different locations), rather than at light speed.
 
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Catastrophe

"There never was a good war, or a bad peace."
Unc,
I just read it in the last couple of days (Quantum Physics Sten Odenwald.). I may be wrong. I have to go check it but, for some annoying reason, it will not allow 'copy' function, so I will need to type it manually. Please give me a little time.

Cat :) :) :)
 

Catastrophe

"There never was a good war, or a bad peace."
OK. I have probably got my interpretation wrong, so please set me right, as you are way ahead of me here:

If one observer detects the polarization of his photon to be ‘up’, then he knows instantly that the observer of the second photon will measure her photon to be ‘dpwn’. But we can make the separation between these observers so large that a light signal does not have time to travel between the observers to guarantee that the other photon is opposite. Since information cannot travel faster than light, we are left with the two photons in what is called an entangled state at macroscopic distances, but nevertheless defined as a single quantum state.
Goes on to EPR.
This is what I was thinking of:
But we can make the separation between these observers so large that a light signal does not have time to travel between the observers to guarantee that the other photon is opposite.

Cat :)
 
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Cat, yes, I realize that is what is being theorized. What I don't know for sure is that it has been proven by experiment that the action at the "far end" happens faster than light could have reached the far end. Seems like that experiment would be tough to do in a universe where we need to communicate at the speed of light or less between the two locations.

I know some experiments, like the double slit experiment, seem to require previous action in one place when something is done in another place (i.e., interference or not). So, that would seem to mean even faster than "instantaneous".

But, if you introduce the concept of tachyons going backward in time, then what happens? Are they the "cause" of the entangled action? If so, and they are going faster than light, is that still "instantaneous"? Or, at extreme distances, is there a time difference between the "cause" and the "effect" (however one decides which is which) because the speed of tachyons is not infinite. (I'm teasing you a bit, since I know you don't like "infinities.)
 
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Catastrophe

"There never was a good war, or a bad peace."
No. Just gets Bell to do the work, I think.

Anyway, this was the bit:

The conclusion from these tests is that particles and observers can remain in complex, estranged states that prevent observers from experiencing a common reality, and that quantum systems do not have fixed properties until the moment of observation. This behaviour is not caused by quantum mechanics being an incomplete theory that needs to be patched up with a superior theory that can provide the missing information.
Cat :)
 
I'll admit that I am lost in the contra-directional time line intersections.

As far as I can take it:

An inebriated tachyon stumbles into a bar, backwards.
The bartender hands him an empty glass.
The tachyon puts his lips to the glass and fills it with whiskey.
The tachyon says "yeksihW"
The bartender (who is multi-temporal, as well as multi-dimensional and multi-lingual) says
"?evahnu uoy ll'tahW".
Then the sober tachyon strides out of the bar with confidence, backwards.

Question: Does the bartender then put the whiskey in the glass into a whisky bottle behind the bar?

Which gets us back to the OP's question about whether photons can carry a virus.

Still "no" and probably not tachyons, either. But, it seems that tachyons could get us tangled up in all sorts of other troubles. ;-)
 
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As far as I know, tachyons are still just hypothesized by some theorists - no proof exists that they exist or cannot exist.

So, "imaginary" or "fictional", they do seem like fodder for a fictional story with some not-disprovable, pseudo-scientific motivational elements.

I think the only real question is whether we have yet driven Billslugg to drink with our extensive whimsical elaborations on his original little joke.
 

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