Hmmm. have you ever tried putting a torch on at night?(Dumb question) You'll see that you can't see miles ahead. You'll only see a few feet in front at most. Same thing. Light loses density after a distance. Which is why if you drive away from a light. Let's say in the middle of a desert. It will appear to get brighter and then get dimmer because light has a greater density than air. .

Club? WTH?

my reasoning tels me that that is wrong.
air is denser then light.
because light doesn't exert presure(?) and air does.
so technicly light doesn't have ANY density.
but then you also have E=mc squared...

my reason is:
light is energy but also a form of 'matter'.
so when light travels it loses energy.
the more energy,the brighter the light+the more energy the light has.

this is what i think so...

oh btw:
club;
The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air.

However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue.

copy and paste of a teaching website.

Oh god... Light doesn't have density, density is a characteristic of objects with mass and volume, neither of which light has... Light has intensity! The intensity of light changes folowing an aritmentic function that decreases with the square of the distance light travels. If you have a light source at x meters from you and another at 2x meters from you the second one will appear to have 1/4 of the intensity of the first. That's why, considering full reflective mirrors, you can't reflect light ad infinitum. Also the ammount of photons is what gives the intensity of light.
Light does NOT have mass but it has momentum, that's why it can eject electrons from atoms or make them change their energy level.

Sorry, I'm a little frustrated! 

Also, let me correct myself, you can reflect light infinitely, but in the end you'll only have one photon, which you cannot see, because photons loose their momentum, therefore reducing the light's intensity.

The matematical function that describes the light's intesity decay tends to zero when the distance tends to infinity. So, you'd actually end up with zero photons if you reflected light endlessly. The photons are the unit of measure for light intensity. They carry light, just as gravitons carry gravity and give it its intensity. Actually, in order to exist light you must have carrying entities on an electromagnetic field, just like the gravitational field. Those particles can be theoretical, like the gravitons and Higgs or real like protons, since it's proven that light has a particle behaviour as well as the wave behaviour:
Quote:


In fact the night vision goggles work by increasing the ammount of photons using a multiplier of sorts...

But take into account that Novas and galactic sized entities have a greater light intensity than the sun alone, therefore they decay less for the same distance. For example the max distance you can see a candle in a black night is about 2 km. If you putted the same ammount of light a galaxy has at that distance you would be blinded even with your eyes closed.

Of course, I'm trying to avoind going into quantum physics here, or else this would be MUCH more complicated... 

Well, the LHC already made some important discoveries. If the Higgs is wrong then that doesn't mean the research was done in vain, it just means we have to search elsewhere for the missing piece.
I kinda like to think that the Universe is like a broken pocket clock with all the infinite pieces laying around and we humans as the person who's trying to put the pieces back together so we can make use of that clock to live a brighter future. Most people think we are in the edge of knowledge but I strongly believe science was advancing more rapidly in the 18 hundreds than in the XXI century. I sure hope things make a twist turn and science and knowledge for the sake of mankind instead of war can have a new bright age.

jetprop wrote on Nov 5^th, 2011 at 12:26pm:


No to all that's in Bold.
Particles are not matter. Matter is particles with mass (atoms).
Photons don't have mass, they are just particles.
Light is NOT matter, you can't grab light with your hand or any other tactile instrument.
Dark matter is not light. Dark matter is a diferent type of matter which is transparent to all types of radiation.
Flat mirrors reflect 90-99% of the light that hits them.

And actually the answer is YES you can reflect light endlessly, but you will stop seeing it after a certain number of reflections, but that doesn't mean there's no light, just like a 10Hz sound is inaudible, but still exists.

Photons have no rest mass. It's mathematically proven.

http://www.desy.de/user/projects/Physics/ParticleAndNuclear/photon_mass.html

And that quote confirms what I've said up there.
Light is not matter. Matter has to occupy a volume and light does not do such thing.

I actually said that as a joke. Guess nobody got it