How you can tell the time of day from shadows cast by the sun. The sun is our main source of light. Nuclear reactions at the core of the sun create energy in the form of heat and light.

How you can tell the time of day from shadows cast by the sun. The sun is our main source of light. Nuclear reactions at the core of the sun create energy in the form of heat and light.

The effect is a thousand sunsets on the lunar ... a celestial fluke—are what cause a total eclipse of the sun. A new moon has two shadows—its fuzzy outer penumbral shadow and dark central ...