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daguin said:
[quote author=Switch link=1213817549/36#41 date=1214224925]I don't think the world is gonna just "die" at a point in time. :p We can survive the harshest environments already, what makes you think every person is just gonna die just like that? Maybe the world as we know it will die, but then again the world is always changing.
The reference is actually to "people", NOT "the world."  You have to read the whole discussion to understand.  Jumping on one word to make a statement is ineffective argumentation.  At best, you should have asked what was meant by "the world."

Peace,
dave[/quote]

I meant the same thing by "the world" :p I think unless there is a really catastrophic natural disaster like a meteor so big Earth will fall on it, there are still going to be some of us left to repopulate later....

light = heat
False.Now go read the thread. :D

BChism, I don't live in the USA.

This just crossed my mind: Ok so light has no mass but it get's bent by gravity because gravity distorts space, and light travels through space.But how come no light would escape the gravitational pull of a black hole?Isn't that related to the light's mass? :-?
 

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GamerBR said:
[quote author=Spyderz20x6 link=1213817549/24#30 date=1213932513][quote author=Diachi link=1213817549/0#10 date=1213878574]Well It might me bear possible, but not completely possible, that would be like having solid light, which isnt possible because light isnt matter it doesnt have a mass .... Kinda confusing, i'll ask my physics teacher, got physics in 1 hour and 20 minutes .

Diachi
Light has very little mass, but it DOES have mass. Imagine a spot of light the size of a nuclear explosion, now imagine a grain of sand. That huge spot of light has the mass of a grain of sand.

This isn't entirely accurate, but it gives you the right idea ;)[/quote]
Actually that's incorrect,it's not like it has close to 0 mass,it has EXACTLY zero mass.
http://en.wikipedia.org/wiki/Photon
[/quote]
That depends on which of two definitions of ’mass’ a particular physicist likes to use, and what type of light you’re talking about.

One definition of mass says that anything which has some gravitational pull on other objects has mass. By that definition, light has mass. This definition of mass is the same as the definition you get if you ask what ’m’ you have to multiply the velocity ’v’ by to get the ’momentum’ of an object. Momentum is a measure of how much stuff is moving which way. When things bump into each other, the total momentum doesn’t change even though it might be traded between the objects. Think of when two balls bounce off each other. Light has momentum, which means we can actually measure the push it gives to objects it runs into. This is the definition used by Einstein, for example in the famous equation E=mc^2.

On the other hand, physicists often find it convenient to think of mass as something that doesn’t depend on how an object is moving, also sometimes called the ’rest mass’. They call the mass of some object the mass that it would have according to somebody who says the object isn’t moving. Light always is moving, so by this definition (or more careful versions of it) a light ray has no mass.

Switching between those definitions can lead to a lot of confusion.

If you have a box of light, with the rays going every direction, the light does contribute to the total mass of the box, by any definition.
 

Ace82

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Science of lasers? :-/ Just tying to expand on an idea. ;)

There are certain phenomenon that could just not be possible, like if the earth's gravitational pull pushed away, or if the absence of energy creating heat, or eating through your ass and shitting out your mouth. No matter how you look at it, the physics are impossible. It would no longer be light. Light is restricted to the boundaries of light, aka wavelengths. Even if you collimate every single possible wavelength laser into a single beam, it will still be very easy to separate again.

Spyderz20x6 said:
That depends on which of two definitions of ’mass’ a particular physicist likes to use, and what type of light you’re talking about.

One definition of mass says that anything which has some gravitational pull on other objects has mass. By that definition, light has mass. This definition of mass is the same as the definition you get if you ask what ’m’ you have to multiply the velocity ’v’ by to get the ’momentum’ of an object. Momentum is a measure of how much stuff is moving which way. When things bump into each other, the total momentum doesn’t change even though it might be traded between the objects. Think of when two balls bounce off each other. Light has momentum, which means we can actually measure the push it gives to objects it runs into. This is the definition used by Einstein, for example in the famous equation E=mc^2.

On the other hand, physicists often find it convenient to think of mass as something that doesn’t depend on how an object is moving, also sometimes called the ’rest mass’. They call the mass of some object the mass that it would have according to somebody who says the object isn’t moving. Light always is moving, so by this definition (or more careful versions of it) a light ray has no mass.

Switching between those definitions can lead to a lot of confusion.

If you have a box of light, with the rays going every direction, the light does contribute to the total mass of the box, by any definition.
Damn that verbiage looks very familiar… ::) back to relativity!
 

keeperx

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you are all arguing this:
http://library.thinkquest.org/13405/intro/lwave.html
vs this
http://library.thinkquest.org/13405/intro/lparticle.html
light is a mystery still even to quantum theroists.. this question asks the age old question, is light a particle or a wave (since thats our understanding of energy)

but as we see light is neither a particle nor a wave. it is not a particle that travels in a wave,
it is not a wave made up of particles,

it travels so fast that it transends time, that is, as the speed of light is aproached, times slows, therfore light is not effected by time since there is no passage of time in 'light land'

Lets think about the universe from the perspective of light. time does not exist. therfore tho we measure speed in people land, speed does not exist (as a distance traveled over a period of time)

if we remove time from ALL our equations and atempt to clasify light outside the boundries of time, we get a very different result.

Distance has no bearing because time is not measured. so for all we know there is just 1 "light" and it exists anywhere and everywhere and nowhere all at the same point (wich is still a measurement of time but i cant seem to get around that in my explination). and our perception of it is imperfect because we are stuck looking at it thru the glasses of time.

Light is not bound by our universal laws. its like a tesseract, percieved imperfectly in our limited universe.
 
L

likewhat

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It really isnt very hard. If you are not near an atomic or molecular etc transition then it is a wave. It is way easier to understand because you can see waves and it behaves in a way that everyone can understand. The fact that it is absorbed in quantized amounts is of no consequence in terms of how it propagates etc. Everything is explained by waves, stop being hard on yourselves.
 
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Hmmm, 0 nm => infinite frequency and each photon would have infinite energy content. That would be a real burner. Photons don't have much of a spatial extent, or its not that well defined as far as I know....but at any rate I'm not aware of any upper limit on the number of photons allowed to occupy a given volume so again you would have one heck of a death ray tending towards or at infinite energy density/power. You wouldn't be able to use such a device as when you turn it on the laser head would receive an impulse of infinite magnitude and accelerate to light speed in zero duration. Basically this device brings up 1/0 everywhere and would probably tear the universe apart. Sounds like a good mod.
 

cybob101

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LikeitBright said:
Hmmm, 0 nm => infinite frequency and each photon would have infinite energy content.  That would be a real burner.  Photons don't have much of a spatial extent, or its not that well defined as far as I know....but at any rate I'm not aware of any upper limit on the number of photons allowed to occupy a given volume so again you would have one heck of a death ray tending towards or at infinite energy density/power.  You wouldn't be able to use such a device as when you turn it on the laser head would receive an impulse of infinite magnitude and accelerate to light speed in zero duration.  Basically this device brings up 1/0 everywhere and would probably tear the universe apart.  Sounds like a good mod.


:'( :'( :'( :'( :'( :'( :'( :'( :'( i like my universe!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

anyone who mods their laser with the above mod will recieve an imminent beating. noone is allowed to rip appart my universe ;D ;D ;D
 




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