I was entranced about 40 years ago when PBS first broadcast Carl Sagan's Cosmos: A Personal Voyage, so this year I decided to give it one final watch. I particularly wanted to revisit his comparison of the stars to grains of sands on earth's beaches. Here are some notes I jotted down while watching all 13 episodes:
Mankind has existed for 40,000 generations. Humans have always viewed the stars as a metaphor for life after death, rebirth, reincarnation because of the cyclicality of the cosmos - a new moon is followed by a crescent moon, the sun rises every day, the constellations rise and fall.It seems appropriate to close with Vangelis' "Heaven and Hell" - the theme song for Cosmos.
There are a hundred billion galaxies containing a billion trillion stars in the observable universe. Those galaxies are typically 300,000 light-years apart.
A handful of beach sand contains about 10,000 individual grains, which is more than the number of stars we can see on a clear night. But the number of stars in the universe is greater than the number of grains of sand on all the beaches of the entire world. [episode 8]
The distance from earth to the center of the Milky Way is about 30,000 light-years.
The distance to the nearest other spiral galaxy is 2 million light-years.
The distance to the ost distant quasar is 8 billion light-years.
The distant galaxies are receding at a speed of 200 million kilometers per hour.
If you postulate that God created the universe, you have to ask where God came from. If this is unanswerable, then just save a step and say the same of the universe. Ditto for the reply that God always existed. Then delete God and say the same for the universe.
"It is the birthright of every child to encounter the cosmos anew in every culture in every age. When this happens to us, we experience a deep sense of wonder. The most fortunate among us are guided by teachers who channel this exhilaration. We are born to delight in the world..."
We humans have set foot on another world in a place called the Sea of Tranquility, an astonishing achievement for creatures such as we, whose earliest footsteps three and one-half million years old are preserved in the volcanic ash of east Africa. We have walked far. These are some of the things that hydrogen atoms do given fifteen billion years of cosmic evolution."