Cosmos #1 - Shores of the Cosmic Ocean

Steven Dutch, Natural and Applied Sciences, University of Wisconsin - Green Bay
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Significant Issues

Personal Voyage

Cosmos is Carl Sagan's personal guided tour of the Universe as he envisions it.

Sagan's Introduction to Cosmos

"The Cosmos is all that ever is, was or will be." Cosmos has hardly begun before Sagan reveals some of his personality. What does this statement mean? If "the cosmos" includes every imaginable entity, for example, God, then the statement is trivially true. That is, it's true, but so what? We don't learn anything we didn't already know. The statement is a tautology: "everything there is is everything there is." Sagan probably means "the material universe is all that ever was, is, or will be", a statement that many people, of course, reject.

Sagan personally was a thoroughgoing materialist, but in his writings he displayed a deeper respect for religion than most people give him credit for. He was especially sympathetic toward the numinous aspect of religions: awe at the power and scope of the Universe.

The other aspect of Sagan that comes across clearly is that he was not afraid to step on toes, an attribute that often earned him the label "arrogant."

"Stars of diamond - atoms as massive as stars." An allusion to some of the exotic forms of matter found in stars. Some dwarf stars have cores of carbon which, according to theoretical calculations, would have a regular arrangement of atoms: a crystalline structure. Neutron stars are essentially gigantic atomic nuclei.

"To find the truth we need both imagination and skepticism. We will be careful to distinguish fact from speculation"

"We are made of star stuff". For the most part, atoms heavier than hydrogen were created in the interiors of stars and then expelled into space to be incorporated into later stars. The Sun is probably a third generation star.

Cosmos got high marks for its use of music. The main theme was written by Vangelis, best known as composer of the score for Chariots of Fire. Also prominent in this program are Beethoven's 7th Symphony (during the montage of human images) and Rimsky Korsakov's Russian Easter Overture (during the re-enactment of 17th-century Holland. Unfortunately, in the VHS videos, some of the best music was replaced with mediocre "elevator music."

A Survey of the Universe

The "ship of the imagination" is a visual convention used throughout the series to move across space and time.

We emerge in a distant cluster of galaxies and head to Earth, on the way getting a feel for the scale of the universe and some basic facts about galaxies.

"The patterns of nature and the laws of nature are the same everywhere." This strikes many people as an outrageously arrogant remark, but in fact there are many observational tests we can make to verify this idea. There have been many theories in physics and astronomy that have postulated changes in the laws of nature over time, but nowhere in the Universe do we see any phenomena that have required physical laws different from those we observe on Earth. Many people have looked for evidence that the laws of physics change in space in time; so far, all such tests have failed. Either the laws of nature vary in such a way that everything just happens to look like things we know from Earth, or the laws of nature really are the same everywhere

Throughout Cosmos, there is extensive use of artists' conceptions. In particular, galaxies are not as bright as pictured in the video. After all, we are just as surrounded by galaxies as any other part of the Universe. If we don't see our night sky splattered with galaxies, intergalactic voyagers wouldn't, either.

Once within the Milky Way Galaxy, Sagan describes the structure of the Galaxy and the concept of star formation.

"Rare forms of matter" Most of the matter in the Universe is either very hot or very cold gas. Solid matter larger than dust grains is relatively rare, liquids rarer still because they can only exist in narrow ranges of temperature. Life, as far as we now know, is still unique to Earth.

The Library at Alexandria

Sagan uses the ancient Library of Alexandria as a recurring theme in the series. He sees it as the birthplace of Western science and as a cautionary symbol of the victory of irrationalism over reason. The library was destroyed and its contents mostly lost. (The actual history is a lot more complex than Sagan implies: the library was repeatedly plundered by Roman emperors to start libraries elsewhere, heavily damaged by Christian mobs and apparently finished off by the Moslems about 650 A.D.)

Eratosthenes was the first person to correctly deduce the size of the Earth, by noting that the elevation of the Sun differed from one place to another. The key observation was that on June 21, the Sun was directly overhead at Syene in southern Egypt, but not in Alexandria. By knowing the difference in elevation angle, and the distance from Alexandria to Syene, he was able to calculate the circumference of the Earth.

Two important morals of Eratosthenes' discovery

Sagan and many other modern writers give Eratosthenes credit for being within a few per cent of the right answer. Older astronomy books once made the error a good deal larger. To make such an assertion, we would have to know:

The plain fact is we simply do not know any of these facts well enough to say he was within only a few per cent, and it's doubtful that Eratosthenes knew any of the first three to be that close. He was in the ballpark, a remarkable enough accomplishment.

The Cosmic Calendar

The Cosmic Calendar compresses the history of the Universe into a year. On this scale:

On this scale, the Universe forms on January 1, but the Solar System does not form until September. Life appears on Earth not long after, but complex life does not appear until December. The dinosaurs appear the day after Christmas. Humans appear at 11 P.M. on December 31, and all recorded history occupies the last ten seconds of the year.

Essential Points

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Created 13 January 1998, Last Update 26 January 1998

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