Travel Faster than a Photon: My 1st Forum Q

[fakts]

My first question on this forum..
I always wondered, what if you could travel faster than a photon? How would it look like traveling? Would it look like a stand still image of where ever is was made? And how would you see the photon if you are faster than it? Doesn't make sense because its not reaching you, or I'm I missing something here?

 

[HallsofIvy]

Based on what fundamental theories?

According to classical physics, It wouldn't look terribly different that traveling slower than photons. Photons from in front of you could still reach you- but but things would appear distorted- shifted to the side. Photons from behind you would not reach you but you wouldn't notice that; photon's from things off to the side slightly would appear to come from behind you and would "fill in" for the missing photons.

If you are asking about relativity, however, you cannot go faster than the speed of light, so you cannot ask the question. You cannot deny part of relativity and then as "what would relativity say"!

 

[fakts]

Thanks HallsofIvy,
Its kind complicated to understand everything you said, I never studied physics but I love it.
Ok, another thing..
What happens to photons that are traveling in an empty direction? will they vanish at certain distance?

 

[jtbell]

If there is nothing for a photon to interact with, it keeps going and going.

 

[milford30]

My first question on this forum..
I always wondered, what if you could travel faster than a photon? How would it look like traveling? Would it look like a stand still image of where ever is was made? And how would you see the photon if you are faster than it? Doesn't make sense because its not reaching you, or I'm I missing something here?

from what i read "a brief history of time" it says in theory time would go backwards if you make a round trip back 2 Earth (a U turn)... that implies after you've U turned you would see a reversed video tape of the history of the Earth? in very fast motion? :P
the above assumes somehow the time stops for you in the view of people on Earth problem is ignored..
of course there are huge problems in this problem :P

 

[milford30]

If there is nothing for a photon to interact with, it keeps going and going.

what about background microwave radiation from big bang? isn't it red shifted some how? or am i missing something and it's interacting with something?

 

[HallsofIvy]

from what i read "a brief history of time" it says in theory time would go backwards if you make a round trip back 2 Earth (a U turn)... that implies after you've U turned you would see a reversed video tape of the history of the Earth? in very fast motion? :P
the above assumes somehow the time stops for you in the view of people on Earth problem is ignored..
of course there are huge problems in this problem :P

I have also read "A Brief History of Time" and it says nothing of the sort.

 

[milford30]

I have also read "A Brief History of Time" and it says nothing of the sort.

maybe i wasn't clear, the spaceship going back in time idea is from "A Brief History of Time", the rest would be what i would predict

 

[ZapperZ]

maybe i wasn't clear, the spaceship going back in time idea is from "A Brief History of Time", the rest would be what i would predict

Maybe you should make an explicit quote out of that book to show us where you got this. Many of us have read the same book (and having physics degrees) and no such claim was made. Time may slowed down, yes, but not "go back".

And in case you might have missed it as a new member, please re-read the https://www.physicsforums.com/showthread.php?t=5374" that you had agreed to.

Zz.

 

[fakts]

from what i read "a brief history of time" it says in theory time would go backwards if you make a round trip back 2 Earth (a U turn)... that implies after you've U turned you would see a reversed video tape of the history of the Earth? in very fast motion? :P
the above assumes somehow the time stops for you in the view of people on Earth problem is ignored..
of course there are huge problems in this problem :P

Well, I thought about it and I think:
If you travel along the photons, observe them and go faster than them then you would probably see a reverse video.
But if you start with the oldest photon and go back toward the newer ones then you would see normal or fast forward video.

Just another question,
Is a photon made out of atoms just like another element?

 

[Rajini]

photon is not made from atoms. But you can say it as a fundamental particle for light (any electromagnetic waves).
It consists of magnetic and electric fields (perpendicular to each other). Mass is zero for photon. These both fields behaves sinusoidally!
For a picture of photons..you can find in any basic physics book..

 

[milford30]

Maybe you should make an explicit quote out of that book to show us where you got this. Many of us have read the same book (and having physics degrees) and no such claim was made. Time may slowed down, yes, but not "go back".

And in case you might have missed it as a new member, please re-read the https://www.physicsforums.com/showthread.php?t=5374" that you had agreed to.

Zz.

sorry about the missing qoute
firstly i assumed everyone understood that in my response i assume faster then light is possible. since it was assumed in starting the topic...

chapter 10 paragraph 12 of my version "A Brief History Of Time" By Stephen Hawking
"If onewent slightly faster, one could even get back before the race and place a bet on it in the sure knowledge that
one would win."

in the illustrated version there's a diagram of the spaceship "U turning" (this is from memory i don't have the illustrated version with me)

i know it's easy to miss a sentence, i only remember it because i remember the diagram from the illustrated version

 

[ZapperZ]

sorry about the missing qoute
firstly i assumed everyone understood that in my response i assume faster then light is possible. since it was assumed in starting the topic...

chapter 10 paragraph 12 of my version "A Brief History Of Time" By Stephen Hawking
"This has been well tested by experiment and is likely to remain a feature even if we find a more advanced theory to replace relativity Thus the moving observer would say that if faster-than-light travel is possible, it should be possible to get from event B, the opening of the Congress, to event A, the 100-meter race.
If onewent slightly faster, one could even get back before the race and place a bet on it in the sure knowledge that
one would win."

in the illustrated version there's a diagram of the spaceship "U turning" (this is from memory i don't have the illustrated version with me)

i know it's easy to miss a sentence, i only remember it because i remember the diagram from the illustrated version

This is different than what you wrote earlier:

from what i read "a brief history of time" it says in theory time would go backwards if you make a round trip back 2 Earth (a U turn)... that implies after you've U turned you would see a reversed video tape of the history of the Earth? in very fast motion? :P

This is what we are disputing.

Secondly, the big "IF" should be emphasized regarding "faster than light", since so far, this is only purely mathematical and unphysical.

Zz.

 

[milford30]

it doesn't matter how big an IF it is, we assumed it in the question... "what if you could travel faster than a photon?" from the first post
how is it different?
if we assumed we can travel faster then light (as also assumed in the text) then the theory does work this way...( the theory in from the text whatever they're using)

 

[elven]

According to the Special Theory of Relativity, going faster than light is not possible, it would require an infinite amount of energy, although tachyons, etc are exceptions. Unfortunately, tachyons were never proven to actually exist, therefore, for now, we can say it is impossible to travel faster than the speed of light.

 

[ZapperZ]

it doesn't matter how big an IF it is, we assumed it in the question... "what if you could travel faster than a photon?" from the first post
how is it different?
if we assumed we can travel faster then light (as also assumed in the text) then the theory does work this way...( the theory in from the text whatever they're using)

If we assume that all the laws of physics doesn't work...

Just because one can ask a question, doesn't mean it makes any sense, or if it is physical. There are many solutions to many problems, even in undergraduate physics, in which you end up with "extra" mathematical solutions that are unphysical.

So far, I think you've been too caught up with this, i.e. the realm of the unphysical, without first understanding the realm of what we already understand (re: your claim that time goes backwards upon reversing travel). Understand the BASIC first before going out on the limb on something still speculative!

Zz.

 

[elven]

Speculation is good, it can broaden your knowledge (although, it can also send it flying out there somewhere). I agree, though, venturing in the realm of the unphysical is good, but understand the one you're in first.

 

[ZapperZ]

Speculation is good, it can broaden your knowledge (although, it can also send it flying out there somewhere). I agree, though, venturing in the realm of the unphysical is good, but understand the one you're in first.

Speculation is "good" only when it is based on knowledge and not ignorance. As scientists, we "speculate" all the time because the nature of our jobs is to explore things that we still do not fully understand. However, speculations based on lack of understanding of the present-day knowledge is crackpottery waiting to happen. The latter is also not allowed, per our PF Rules.

Zz.

 

[elven]

Exactly, you must have a base for speculation, although, not only scientists speculate upon that which we do not understand. As humans, our nature is to attempt to understand that which we do not yet understand.

 

[milford30]

hmm... actually your right it was my mistake it should be in forward motion...

i don't see a huge difference between this and Einstein's day dream of sitting on a beam of light...

 

[milford30]

Speculation is "good" only when it is based on knowledge and not ignorance. As scientists, we "speculate" all the time because the nature of our jobs is to explore things that we still do not fully understand. However, speculations based on lack of understanding of the present-day knowledge is crackpottery waiting to happen. The latter is also not allowed, per our PF Rules.

Zz.

current does not imply it's right... anyone that thought the Earth was round a few thousand years ago would be considered a crackpot...
if future humans look back, they'll most likely think we're blind to the 'actual' truth...
i have just extended the idea from "a brief history of time", sure i made a careless mistake, when your ship's coming back you'll see photons head on, and the most recent happenings would be the latest ones so it's forward...

 

[elven]

current does not imply it's right... anyone that thought the Earth was round a few thousand years ago would be considered a crackpot...
if future humans look back, they'll most likely think we're blind to the 'actual' truth...
i have just extended the idea from "a brief history of time", sure i made a careless mistake, when your ship's coming back you'll see photons head on, and the most recent happenings would be the latest ones so it's forward...

That's right, current does not imply that it is correct. However, the term 'correct' is relative. Think about it this way: when someone formulates a valid unification theory, our Forces will be considered crackpottery, as well as your analogy 'anyone that thought the Earth was round a few thousand years ago would be considered a crackpot...' therefore, assume that what is current, is correct. For now... Things are always changing, and knowledge changes with it.

 

[HallsofIvy]

current does not imply it's right... anyone that thought the Earth was round a few thousand years ago would be considered a crackpot...

Even that statement is not true. Any educated person, back as far as the ancient Greeks, knew that the Earth was round. In fact, Eratosthenes calculated the radius and circumference of the Earth about 2050 years ago.

if future humans look back, they'll most likely think we're blind to the 'actual' truth...
i have just extended the idea from "a brief history of time", sure i made a careless mistake, when your ship's coming back you'll see photons head on, and the most recent happenings would be the latest ones so it's forward...

 

[elven]

Remember, he said 'considered', also, the church dominated at that time, so they were considered crackpots, even if they weren't.

 

[milford30]

Even that statement is not true. Any educated person, back as far as the ancient Greeks, knew that the Earth was round. In fact, Eratosthenes calculated the radius and circumference of the Earth about 2050 years ago.

ok maybe a better example would be the Earth revolving around the Sun... this example should be clearer

 

[ZapperZ]

This should not be turned into a debate on what "valid speculation" really is. The rules of this forum are very clear, and you all agreed to it!

If you've published many papers in physics journals and can show that you've mastered the subject matter, then I would LOVE to hear your speculations. I do that almost every week when I attend my division's colloquium. Till then, if you still are not familiar with the prevailing knowledge that we have accepted to be valid, for whatever range of validity, then you shouldn't make such speculation. If you don't like this, then read all the threads in the feedback forum that made similar complaints already. All our responses are already written a gazillion times.

Zz.

 

[fakts]

This should not be turned into a debate on what "valid speculation" really is. The rules of this forum are very clear, and you all agreed to it!

If you've published many papers in physics journals and can show that you've mastered the subject matter, then I would LOVE to hear your speculations. I do that almost every week when I attend my division's colloquium. Till then, if you still are not familiar with the prevailing knowledge that we have accepted to be valid, for whatever range of validity, then you shouldn't make such speculation. If you don't like this, then read all the threads in the feedback forum that made similar complaints already. All our responses are already written a gazillion times.

Zz.

Well, I searched the forum before I posted, I didn't find anything close to my question, also some people don't mind answering some noob questions, also I don't think you have to have a degree in physics to have the right to ask. You sound so touchy and you made me feel like in a concentration camp, jeez

 

[ZapperZ]

Well, I searched the forum before I posted, I didn't find anything close to my question, also some people don't mind answering some noob questions, also I don't think you have to have a degree in physics to have the right to ask. You sound so touchy and you made me feel like in a concentration camp, jeez

You will note that I didn't say there was anything wrong with your question. If there was, I would have replied to your post. So I'm not sure where you are getting such an impression. When you are given a reply that such a question really isn't quite valid, it isn't a criticism on the question, but rather an answer, because some questions are ill-defined due to the nature of the physics. You can ask what color pain is, but it doesn't mean that it has any meaning.

So far, unless our physics develops further, motion faster than c is still unphysical. There have been a series of "gymnastics" that produced apparent motion that's larger than c (i.e. the NEC experiment), but none of these have broken the basic tenets of SR.

We continue to get questions like this in this forum, and we have continued to address them. However, unless one understand the issues and the physics of SR, trying to extrapolate beyond this requires unfounded speculations, which is something we do not recommend.

Zz.

 

[fakts]

ZapperZ
Well clarified, everything is ok
Its just you sound like a scientist and you know lots and lots about physics, I didn't get the chance to study it but I love it and the more I know about the more I want to know.

So what sounds for you an obvious, for me is still a mystery, its like explaining to someone who was born blind what color is!

You will have to be alittle patient :D

 

[cragar]

in a nuclear reactor neutrons travel faster than photons in the water , this is called cerenkov
radiation , although someone will probably say that photons only appear to slow down in different media and that they always travel at c .
and I might add that they can slow down light to like 38mph by passing it through an Einstein -Bose condensate , so in a sense you can travel faster than a photon , but not c .

 

[ZapperZ]

in a nuclear reactor neutrons travel faster than photons in the water , this is called cerenkov
radiation , although someone will probably say that photons only appear to slow down in different media and that they always travel at c .
and I might add that they can slow down light to like 38mph by passing it through an Einstein -Bose condensate , so in a sense you can travel faster than a photon , but not c .

This is not quite relevant to the thread, since we're talking about speed of photon, and not group velocity of light.

Zz.

 

[cragar]

boy you really are a physicist , my mistake

 

[DannoXYZ]

According to the Special Theory of Relativity, going faster than light is not possible, it would require an infinite amount of energy, although tachyons, etc are exceptions. Unfortunately, tachyons were never proven to actually exist, therefore, for now, we can say it is impossible to travel faster than the speed of light.

Only for things that have mass. There are mass-less objects that aren't constrained by this rule.

 

[Vanadium 50]

Not true. Massless objects cannot go faster than light either.

 

[Hernik]

I have better make a disclaimer: I am not a physicist. But I might be able to help you on comprehending why it is not possible to go any faster than c according to Einstein.

SR tells us that the faster you move, the more space contracts in the direction of your travel. Distances simply get shorter in front and behind you. When you reach the speed of light in vacuum the contraction of space in the direction you travel is absolute. There is no distance left. Everything in front of you and behind you in the entire universe is right where your are. So you arrive instantly. It is hard to see that it would be possible to reach somewhere any faster than instantly, isn't it?

- Henrik