Why does chlorophyll always fluoresce in red?

[poobear]

Regardless of the color of the light, chlorophyll always fluoresce red light.
I think I understand the basic principles of fluorescence, but I dont understand why it always is red light from chlorophyll.
Is there any easy explanation to this that even I understand?

Thanks

[MrMistery]

think of it like this: a change machine converts a dollar bill to a quarter, and keeps 75% of the money. every time you put a dollar bill, you get a quarter. Now if you throw a whole bunch of different bills at the machine, only the 1 dollar bills will make a difference, and it will always give out quarters. Chlorophyll only absorbs a certain wavelength (in the UV spectrum if I am not mistaken) and gives out red.

[miloshic]

I think it's not right. As I remember, we had some other colours, maybe black... Chlorophyle absorbs red and blue light, but it reflects green light. Find it somewhere, I'm not sure

[mith]

look up the definition of fluoresce.

[BlackCat]

as miloshic said chlorophil a absorves in red and blue. Blue light is much more energetic than red, so when a blue photon strikes the chlorophil, it change from a basal state to a very excited state. To get to a lowest excited state it loses energy by heat. When striked by a red photon, chlorophil changes to that lower excited state and to get to the basal state it looses energy by re-emitting red photons.
Thats why chlorophil a always fluoresce on red...