Air like things are colourless means, they can't emit visible light when light falls on it ? Is not it?

Question

Actually I am unable to expess my doubt clearly. Means if air particles are present we have to see dark space , because all the light is obsorbed by the air particles. But we are not seeing dark, we are seeing light where air is present.

Answer 1

Hello,
Air is , as we all know, matter in molecular (gaseous) state. Even in a very large volume of air, the number of molecules will be very very small compared to solid or liquid i.e; the density is less.
These molecules scatters as well as absorbs light. Considering a single molecule, the absorbtion is negligible compared to the light reflected by it. Molecules cannot be seen by our eyes. Reflected light being maximum, we see light and not darkness.This scattering is the reason we see light in the shades under trees etc, where no direct sunlight falls. Now, the light absorbed is used by its electrons to increase its energy levels.
Absorbtion is more when the air is filled with smoke and dust. They, being dense, absorbs more light and you see darkness.

Answer 2

air does reflect or refract light, that's why the sky is blue, however it takes LOT of air to scatter all of this light. So the air near you appears to be invisible as only a very very small of light is scattered off of it. Air molecules are so small and moving so fast, the light basically goes right through it.

Answer 3

The most direct evidence is probably the orbital velocity around the black hole. If you know the period and size of an object's orbit, you can calculate the mass that the object is orbiting. This can apply to either discrete objects like stars, or clouds of gas and dust. In some cases, the mass at the center is so large that the mass concentration is clearly that of a black hole. The fact that the light of an equivalent mass of stars is not coming from the central mass is further evidence of a probable black hole. Although we can't see any energy from black holes themselves, the disk of gas and dust around them emits energy as matter spirals inward. And black holes are thought to emit energy, called Hawking radiation, but for large black holes it is infinitesimal.

Answer 4

Transparent things allow light to pass through, not absorb it.