Dr. Christopher D. Impey is the Distinguished Professor of Astronomy and the Steward Observatory at the University of Arizona.
On February 4, 2013 Dr. Impey gave the Dean Lecture at the Morrison Planetarium in the California Academy of Sciences in Golden Gate Park in San Francisco. You can find the recording of his lecture on the California Academy of Sciences website. I attended this lecture and found him to be very knowledgeable entertaining.
This video is a short history of the cosmos and tells about the origin of the universe and the big bang.
What choice would you make in the following picture?
What is your answer?
Dr. Impey said that the universe is made up of normal matter and radiation. The universe is more than 99.9% hydrogen and helium. What can you make with just hydrogen or helium? Nada! He said, “It would be a dull universe without stars!” The .1% consists of the elements that we need for life.
There are 1080 atoms in the universe and a billion photons for every atom. Most of the photons are microwave photons left over from the big bang.
Most of the atoms are in the 100,000 billion billion (1023) stars which are divided into 100 billion galaxies, each with 100 billion stars. Wow! This is just in the visible universe!
All of these atoms and radiation make up only about 4.6% of the known universe. The rest is made up of 24% dark matter and 71.4% dark energy.
The best guess is that there are a billion billion Earth-like planets out there somewhere in the whole cosmos!
So, here we are on an average planet orbiting a mid-sized star in an average galaxy near a medium-sized cluster in an unremarkable corner of a very large universe!
The upshot of all this is that we are made of stardust. Everything on Earth once existed in a star.
How does it make you feel when you know you were once upon a star? Please share.
Note: much of what you read here today will be incorporated into my next book, Cosmology and Buddhist Thought: Conversations with Dr. Neil deGrasse Tyson.. Watch for it on Kindle Books!
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