Wednesday, September 12, 2012

Two Crescents

Venus and the waning crescent moon this morning.

Four centuries ago when Galileo saw through his telescope that Venus was also a crescent, he knew that the Sun was the center of the solar system, not Earth. He knew because if the Sun and Venus were both going around the Earth, Venus would never be a crescent, it would always appear gibbous to us.

1 comment:

Lora said...

I just shared this with co-workers, and we all had an ah-ha moment.

Thank you.