opposite of light

[pinestone]

Emission of a specific band of wavelengths results in what we call 'light'.

If there is such a thing as the 'balance of nature' (ie. 2nd law), then what is the opposite of light?

It's not darkness (that's the absence of light).

Use a black hole for example. Light can not escape, therefore we can not 'see' it.
If these 'negative' photons are traveling 'away from us', shouldn't we call them 'dark' and address them as such?

[Larbear]

2nd Law of what (thermodynamics, newtons laws, us constitution) there are a whole lot of laws out there?

As for the motion of photons, they are moving everywhere around us, sometimes towards us sometimes away, we just dont see it until it reflects back to us. Say your standing with the sun behind you looking at a tree. The photons must travel past you and hit the tree and come back to you before you can see the tree.

For the blackhole question, picture the photon as a tennis ball, On the moon, i can throw that tennis ball and itll go off into oblivion, however on earth, the tennis ball is going to come back down. We dont call it a negetive tennisball just because it can escape though.

Are these serious postulations, or just philisophical conundrums that you are asking?

[pinestone]

2nd Law of what (thermodynamics, newtons laws, us constitution) there are a whole lot of laws out there?

As for the motion of photons, they are moving everywhere around us, sometimes towards us sometimes away, we just dont see it until it reflects back to us. Say your standing with the sun behind you looking at a tree. The photons must travel past you and hit the tree and come back to you before you can see the tree.

For the blackhole question, picture the photon as a tennis ball, On the moon, i can throw that tennis ball and itll go off into oblivion, however on earth, the tennis ball is going to come back down. We dont call it a negetive tennisball just because it can escape though.

Are these serious postulations, or just philisophical conundrums that you are asking?

Sorry, I assumed 'the balance' was known as the 2nd law of thermodynamics.

You are giving examples of reflection or refraction. This is a serious question.
Why has it not been discussed before?

[DaveC426913]

If there is such a thing as the 'balance of nature' (ie. 2nd law)
There isn't. At least, not in physics.

The 2nd Law talks about entropy. What does it that have to do with 'balance of nature' woo-woo-ism?




Use a black hole for example. Light can not escape, therefore we can not 'see' it.
If these 'negative' photons are traveling 'away from us'
non sequitur. How did you get from 'things we can't see' to 'negative photons'?
To use a trivial analogy: My dog can't escape from my house, that doesn't make him a negative dog.

This is a serious question.
Then you'll need to use correctly-defined physics terms and concepts.

[pinestone]

There isn't.


non sequitur. How did you get from 'things we can't see' to 'negative photons'?
To use a trivial analogy: My dog can't escape from my house, that doesn't make him a negative dog.


To get a serious answer, you'll need to use correctly-defined physics terms and concepts.

2nd law of thermodynamics:
"Processes that decrease total entropy of an isolated system do not occur. If a system is at equilibrium, by definition no spontaneous processes occur, and therefore the system is at maximum entropy" - http://en.wikipedia.org/wiki/Second_law_of_thermodynamics

Well, considering there's no 'correctly-defined physics terms' to properly describe this thought experiment, my words in quotes are a 'rough draft' of something abstract and not easily communicated. And, I agree- the black hole scenario is not a good analogy now that I think about it in greater depth.

So, let me re-phrase the whole thing...what does one call the 'opposite of light'?

Seriously

[DaveC426913]

So, let me re-phrase the whole thing...what does one call the 'opposite of light'?

Seriously
Dark.

No really. I know that's not the answer you want, but you are the one claiming that there has to be some more substantial opposite. Why do you insist so?

What's the opposite of hot? Cold. (Wrong: there is no such thing as cold; there is only absence of heat. Cold is an organism-derived relative comparison between two temperatures (both of which are heat)).

A more generalized and more fundamental version of the same thing: Q: what's the opposite of the universe/existence? A: Nothing/Oblivion. i.e. in any meaningful way, the opposite of something that exists is its absence.

[pinestone]

Dark.

No really. I know that's not the answer you want, but you are the one claiming that there has to be some more substantial opposite. Why do you insist so?

What's the opposite of hot? Cold.

A more generalized and more fundamental version of the same thing: Q: what's the opposite of the universe/existence? A: Nothing/Oblivion. i.e. in any meaningful way, the opposite of something that exists is its absence.

I'm not looking for an answer, Dave
It's just a thought experiment down a road untraveled. What doesn't have an opposite?

So you think the compliment of light is 'nothing'. If light is traveling in a direction 'X' it can be refracted, reflected or absorbed. But the compliment of light should travel in a direction of 'minus X' ......Right ????

[shamrock5585]

but that is the direction it is travelling not what it is

[Larbear]

Agreeing with Dave

And thats what the 2nd law is saying, that all systems are trying to move towards no spontaneous reactions, that is the function of light. When particals reach to high of an energy level they drop thier electrons to a lower shell by releasing a photon. That photon travels until it hits a partical that can absorb this extra energy.

Light doesnt need an opposite to satisfy the rule of increasing entropy, it is the solution to particles not meeting that state of equilibrium.

2nd law doesnt state that there are opposites, it just says that eventually everything will reach a balance where it wont absorb or let of energy. I think your confusing equilbrium balance with traditional chinese spiritual balance, entropy has nothing to do with ying and yang!

[Larbear]

So you think the compliment of light is 'nothing'. If light is traveling in a direction 'X' it can be refracted, reflected or absorbed. But the compliment of light should travel in a direction of 'minus X'

a car traveling in reverse is still a car

[shamrock5585]

Agreeing with Dave

And thats what the 2nd law is saying, that all systems are trying to move towards no spontaneous reactions, that is the function of light. When particals reach to high of an energy level they drop thier electrons to a lower shell by releasing a photon. That photon travels until it hits a partical that can absorb this extra energy.

Light doesnt need an opposite to satisfy the rule of increasing entropy, it is the solution to particles not meeting that state of equilibrium.

2nd law doesnt state that there are opposites, it just says that eventually everything will reach a balance where it wont absorb or let of energy. I think your confusing equilbrium balance with traditional chinese spiritual balance, entropy has nothing to do with ying and yang!

this law applies to temperature as was discussed before... when you put an ice cube into a hot cup of coffee the ice cube is not actually "cooling" the cup of coffee in a literal sense... the hot coffee is distributing its heat to the ice cube melting it and distributing the energy uniformly which is "diluting" it... and then the coffee will distribute the energy uniformly to the room... and the room to the earth and the earth to the universe eventually.

[Larbear]

Which eventually means that the entire universe will reach the same temperature!
(hopefully in the upper 80's for comfort :P )

Hopefully this makes sense to you pinestone. Nothing has to have an opposite but rather a lack thereof, so that it eventually reaches the same temperature!

Unfortunately, what this also means is that there is no perfect alternative fuel, and no matter what we do, every action we take, we are killing the universe! (in a metaphorical sense, obv the universe is not living, but a state in which nothing can move or happen is as good as dead to me!)

[pinestone]

but that is the direction it is travelling not what it is

Yes, but we call it light because it's an emission away from the source.
if the travel was 'inward' could we still call it 'light'?


Agreeing with Dave

And thats what the 2nd law is saying, that all systems are trying to move towards no spontaneous reactions, that is the function of light. When particals reach to high of an energy level they drop thier electrons to a lower shell by releasing a photon. That photon travels until it hits a partical that can absorb this extra energy.

Great explaination- but what happens if the particles reach a lower energy level?
Could that result in an in-ward travel ?


Light doesnt need an opposite to satisfy the rule of increasing entropy, it is the solution to particles not meeting that state of equilibrium.

Taking the above statement into consideration, what about the opposite state of decreasing entropy- such as time-invarient conditions?


2nd law doesnt state that there are opposites, it just says that eventually everything will reach a balance where it wont absorb or let of energy. I think your confusing equilbrium balance with traditional chinese spiritual balance, entropy has nothing to do with ying and yang!
I'm not thinking spiritually, just logically. There are theories of parallel universes, multiple strings and the like- what's so difficult in the concept of 'negative' light?



a car traveling in reverse is still a car

Yes, you are right. Reference my reply to shamrock5558 (above)

[shamrock5585]

this brings up the interesting fact that energy and matter are forms of one and the same thing... but we have matter, anti-matter and energy... is there anti-energy or just lack thereof.

[nuby]

I've thought about this before as well.

Can anything in nature exist without an opposite? You've got matter and antimatter. So, how can the opposite of light be "no light" and cold "no heat" .. Wouldn't this be the same as saying the opposite of matter is "no matter" ... repulsion is to "no repulsion" ... The answer is probably just nobody knows for sure.

[turbo-1]

There is an opposite to the emission of light, and that is the absorption of light. Astronomical spectroscopy relies on the accurate measurement of both emission and absorption, and the displacement of these lines from those of terrestrial standards is considered to be due to cosmological expansion. Using the displacement of these lines, the apparent distance of the observed object is extrapolated from the Hubble redshift/distance relation.

[shamrock5585]

i guess to elaborate on my question before... anti-matter still has mass... can mass be negative? just a thought to ponder.

pinestone you need to realize that by the car analogy he is just showing that you are not describing negative light you are just talking about light being emitted in the opposite direction. It is still light though.

[pinestone]

There is an opposite to the emission of light, and that is the absorption of light.

Is is feasible to imagine a 'stand-alone' absorber that 'sucks' light into itself and re-emits it the opposite direction (ie. lower energy state)? There would be no apparent way to observe this phenomenon, but as a logical thought experiment I think it's an interesting concept.

[DaveC426913]

Yes, but we call it light because it's an emission away from the source.No, that is not why we call it light, and this may be the crux of your confusion.

Note that we do not see the light emitted from the Sun until it is absorbed by our eyes. i.e. it is light whether being emitted or absorbed.

Perhaps your question is more accurately 'what is the opposite of the emission of light'. To which the answer is: the absorption of light.

[DaveC426913]

Is is feasible to imagine a 'stand-alone' absorber that 'sucks' light into itself and re-emits it the opposite direction (ie. lower energy state)? There would be no apparent way to observe this phenomenon, but as a logical thought experiment I think it's an interesting concept.
Sure. An ashphalt roadway absorbs sun light in the visible spectrum and emits it in the infrared spectrum.

[pinestone]

i guess to elaborate on my question before... anti-matter still has mass... can mass be negative? just a thought to ponder.

pinestone you need to realize that by the car analogy he is just showing that you are not describing negative light you are just talking about light being emitted in the opposite direction. It is still light though.

Oh, I understand and agree. Hot and cold = temperature. Up/down = direction.

However, light/dark are not opposites. This is the reason for my post.
Light is an emission and dark is the lack of reflection/refraction (or the act of being absorbed)

[pinestone]

Sure. An ashphalt roadway absorbs sun light in the visible spectrum and emits it in the infrared spectrum.

Yes, that's kind of what I'm referring to. But this scenario is more like reflection- the energy is still traveling in the same direction.

Isn't this fun?

[pinestone]

No, that is not why we call it light, and this may be the crux of your confusion.

Note that we do not see the light emitted from the Sun until it is absorbed by our eyes. i.e. it is light whether being emitted or absorbed.

Perhaps your question is more accurately 'what is the opposite of the emission of light'. To which the answer is: the absorption of light.

Oh, I'm quite aware we 'consume' photons during the visual process. I think its the best 'food for thought'-
We are a receiver. The sun is a transmitter. What's the opposite of explode?

[DaveC426913]

However, light/dark are not opposites.No, not really. And cold and heat are not opposites either; one is illusory.

Speed has no opposite either. There is speed and there is the absence of speed. (I was going to say velocity but that's a vector, so it does have an opposite, namely -v)

The point is that not everything has an opposite. I still want to know why you think everything has to have a substantive opposite.

[WarPhalange]

The opposite of light is anti-light. Since light is made up of photons, anti-light is made up of anti-photons.

But wait! It turns out that the anti-particle for the photon is the photon, ergo light is its own opposite. HOORAY!!

[nuby]

Speed isn't an physical object, so that doesn't count. It's a measurement.

[K.J.Healey]

The opposite of light is anti-light. Since light is made up of photons, anti-light is made up of anti-photons.

But wait! It turns out that the anti-particle for the photon is the photon, ergo light is its own opposite. HOORAY!!

I agree with this.

[pinestone]

I agree with this.

So the anti-photon is light. Sounds OK with me.

We have a winner- the opposite of light....wait for it....




IS LIGHT !

but we'll never see it.

OOPs- seems a little research turned up this tid-bit:

"Some particles have no antiparticles; these include the photon, the hypothetical graviton, and any other hypothetical massless gauge bosons"- http://en.wikipedia.org/wiki/Antiparticle

[K.J.Healey]

Or you could say that it doesn't have an opposite. Its a particle that doesn't transform in the way you are using to make "opposites". Invariant under whatever you're defining. So it has no opposite.

[DaveC426913]

So the anti-photon is light. Sounds OK with me.

We have a winner- the opposite of light....wait for it....




IS LIGHT !

but we'll never see it.

What?? Yes we will.

KJHealey is correct in that a photon's anti-particle is, in fact, a photon. A photon emitted from an antimatter atom (anti-electrons around anti-proton nucleus) is still a photon. Matter and anti-matter look identical from a distance because the photons tell us nothing about which it is.

But it's still just light and we'll see it just fine.

[shamrock5585]

the article states it clearly... there is no antiphoton hence the opposite of light is the absense of light... darkness! if a photon is a photon and an anti-photon how does that make sense... my name is Bryan... you can call me Jon cuz thats my name too!

[pinestone]

the article states it clearly... there is no antiphoton hence the opposite of light is the absense of light... darkness! if a photon is a photon and an anti-photon how does that make sense... my name is Bryan... you can call me Jon cuz thats my name too!


Geeeze- darkness and light. Now I'm gonna get banned. I think this may be headed into metaphysics (which is a no-no around this place).

So we're back to my first post on this thread- anti-light...aka 'dark'

Gotta love it.

[shamrock5585]

u got your answer you just refused to believe it!

[DaveC426913]

I think this may be headed into metaphysics (which is a no-no around this place).Actually, it started in metaphysics - with the very first line about 'balance of nature' - and never left it.

[pinestone]

Actually, it started in metaphysics - with the very first line about 'balance of nature' - and never left it.

Yea, sorry about that 'non-physics' statement-

Entropy, entropy, entropy. I'll get it eventually...after all, who cares about the physical multiverse when you are studying physics?

:smile:

u got your answer you just refused to believe it!

I never said I didn't believe it. It's just a good exercise to stretch ones mind now and then.


By the way, no one answered my question...what's the opposite of explode?

[russ_watters]

This is asinine. It's not even worthy of GD.