Earth

EARTH

LIGHT

How long does it take our sun's light to reach us?
The speed of light c is = 299 792 458 [m/s] (meters/second)
Our sun is about 149 597 890 000 [m] from earth
It takes sunlight about 500 seconds (8 minutes and 20 seconds) to reach us

<-- high energy low energy -->

<-- high frequency/short wavelength low frequency/long wavelength -->

<-- ultraviolet infrared -->

wavelength=400nm wavelength=750nm

Underwater
30' below - red disappears
- orange disappears
- yellow disappers
- green disappears
- violet disappears

The euphotic depth is the depth at which light intensity falls to 1% of the value at the surface.
At the euphotic depth, plants have no net energy gain from photosynthesis and thus cannot grow.