Pale Blue Dot - Carl Sagan

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Jim Colyer
I reread Sagan's book and wrote this piece:
http://jimcolyer.com/papers/entry?id=459;fa=4

PALE BLUE DOT: A VISION OF THE HUMAN FUTURE IN SPACE - CARL SAGAN

Carl Sagan uses two pictures in lecturing from his pulpit. The first is the iconic photo of Earth taken in 1972, by the astronauts of Apollo 17. The earth appears as a "blue marble." Africa is seen at the top (I wish it were North America) while Antarctica appears at the bottom. We see blue oceans and white cloud tops. In the second picture, the earth appears as a "pale blue dot." This picture was taken by Voyager 1 in 1990, 3.7 billion miles away. Our planet is no larger than a speck, and Sagan goes to great lengths to convince us how arrogant and inconsequential we are. In the picture known as "The Pale Blue Dot," Earth is seen against a beam of light caused by sunlight reflecting off the spacecraft. Sagan remarks that this view of Earth would be seen from any alien spacecraft entering our solar system and that its occupants would have no reason to think this tiny point of light was of any significance.

Geocentrists are Sagan's bad guys as he presents us with a series of demotions. Not only is the earth not at the center of the solar system, but the sun is not at the center of the Milky Way and the Milky Way is merely one galaxy among billions and billions. Finally, we are not even at the center of the expanding universe because there is no center. An observer in any galaxy would perceive all the other galaxies receding from him. Sagan's book was published in 1994, years before the Kepler spacecraft found exoplanets. Nonetheless, he foresaw it happening. He recognizes the Bible and Koran as moral guides but understands that they reflect the rudimentary science of the times in which they were written. The earth is 4.7 billion years old, not 6 thousand years old as the Bible suggests. The universe itself has been around for 13.8 billion years. Sagan portrays the human species as a newcomer. It is in no way privileged. Although he stops short of saying religion is crap and there is no such thing as "God," he writes that "we seem compelled to project our own nature onto Nature." Sagan hints at a multiverse, infinitely old and unobservable, ultimately stripping us of all notions of being special. He comes off as a John Lennon shoving humility down our throats. Still, Sagan is a brilliant man who knows his stuff. He sees order and design as stemming from the laws of nature rather than from any kind of deity or designer. We are responsible for ourselves.

Carl Sagan has high praise for the Voyager 1 and Voyager 2 missions. Launched in August and September, 1977, they opened the solar system up over a 12 year period. Much was learned about the four gas giants. All four were found to have rings, and volcanoes were discovered on Jupiter's moon, Io. Thousands of new rings were discovered around Saturn while Saturn's moon, Titan, became an object of great interest. With its methane-rich atmosphere, Sagan seems to suggest that life could eventually rise. Sadly, he did not live to see the Cassini spacecraft reach Titan.

Voyager 2 reached Uranus in 1986, and Neptune in 1989. Uranus' moon, Miranda, mystified astronomers with its bizarre terrain. Neptune's moon, Triton, exhibited an atmosphere similar to Titan's. Because it is thinner, we are able to see Triton's surface. Sagan concludes that the only life in our solar system is on Earth. He envisions the Voyagers flying 5 billion years into the future, long after humans have become extinct or evolved into something else.

Sagan was always a planet guy, and he devotes space to Venus. The ancients thought the "evening star" and the "morning star" were different. They did not realize they were one and the same, the planet Venus revolving around the sun. Venus is an inferno, permanently overcast. Its clouds reflect sunlight back into space.

Sagan assumes that Mars once had water and possibly life. He writes that things went wrong about 3.8 billion years ago, that the atmosphere thinned and the oceans and rivers dried up. His view is the predominate one today. Sagan wanted to explore Mars with robots, and such has been the case. Spirit and Opportunity roamed the red planet. And now Curiosity.

Although Sagan saw the end of the Cold War and increased cooperation between the United States and Russia, he died before 9/11. Muslim terrorists created a paranoia that was nonexistent in the 1990s. The general public is not clamoring for a man on Mars. Sagan proposed in his book that any manned mission to Mars should involve cooperation between the spacefaring nations: United States, Russia, European Space Agency, Japan and China. Better watch out for those cosmic rays!

Sagan devoted a chapter to Apollo 11. He was impressed with the surrealism of the moonwalks and notes that the Apollo program was about politics, not science. To control space was to control Earth!

Sagan wrote about the Search for Extraterrestrial Intelligence (SETI and how radio waves from space might be evidence of an alien civilization. Frank Drake started SETI in 1960. The SETI Institute in Palo Alto, California, continues his search. Results have been negative.

Light travels at a finite speed of about 186,000 miles per second. It takes light less than 2 seconds to travel from the moon to Earth. It takes 8 minutes for it to travel from the sun to Earth. If a technological alien civilization exists 300 light-years away, it will take 300 years for it to receive our radio signals. It will take another 300 years before we get a reply.

Oneness
No song lyrics?

I am big fan of Carl Sagan; and his ideas on using science to find better perspectives than those offered by religions.

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