If you hold up a grain of sand, the patch of sky it covers contains 10,000 galaxies.

There are at least one hundred billion galaxies in the observable universe.

This is our galaxy, the Milky Way Galaxy. It is just one of those 100 billion galaxies.

The band of the Milky Way stretching across the Wyoming sky in Grand Teton National Park. Photograph by Babak Tafreshi, National Geographic

The Milky Way Galaxy contains about 100-400 billion stars. Our Sun is just one of those stars.

What are the chances that life as we know it came about only on our one planet attached to our one star? What about intelligent life? How would you define “intelligent life”?