The Demon-Haunted World_ Science as a Candle in the Dark - Carl Sagan [161]
• The ancient Aztec and the ancient Greek words for ‘God’ are nearly the same. Is this evidence of some contact or commonality between the two civilizations, or should we expect occasional such coincidences between two wholly unrelated languages merely by chance? Or could, as Plato thought in the Cratylus, certain words be built into us from birth?
• The Second Law of Thermodynamics states that in the Universe as a whole, disorder increases as time goes on. (Of course, locally worlds and life and intelligence can emerge, at the cost of a decrease in order elsewhere in the Universe.) But if we live in a Universe in which the present Big Bang expansion will slow, stop, and be replaced by a contraction, might the Second Law then be reversed? Can effects precede causes?
• The human body uses concentrated hydrochloric acid in the stomach to dissolve food and aid digestion. Why doesn’t the hydrochloric acid dissolve the stomach?
• The oldest stars seem to be, at the time I’m writing, older than the Universe. Like the claim that an acquaintance has children older than she is, you don’t have to know very much to recognize that someone has made a mistake. Who?
• The technology now exists to move individual atoms around, so long and complex messages can be written on an ultra-microscopic scale. It is also possible to make machines the size of molecules. Rudimentary examples of both these ‘nano-technologies’ are now well demonstrated. Where does this take us in another few decades?
• In several different laboratories, complex molecules have been found that under suitable conditions make copies of themselves in the test tube. Some of these molecules are, like DNA and RNA, built out of nucleotides; others are not. Some use enzymes to hasten the pace of the chemistry; others do not. Sometimes there is a mistake in copying; from that point forward the mistake is copied in successive generations of molecules. Thus there get to be slightly different species of self-replicating molecules, some of which reproduce faster or more efficiently than others. These preferentially thrive. As time goes on, the molecules in the test tube become more and more efficient. We are beginning to witness the evolution of molecules. How much insight does this provide about the origin of life?
• Why is ordinary ice white, but pure glacial ice blue?
• Life has been found miles below the surface of the Earth. How deep does it go?
• The Dogon people in the Republic of Mali are said by a French anthropologist to have a legend that the star Sirius has an extremely dense companion star. Sirius in fact does have such a companion, although it requires fairly sophisticated astronomy to detect it. So (1) did the Dogon people descend from a forgotten civilization that had large optical telescopes and theoretical astrophysics? Or, (2) were they instructed by extraterrestrials? Or, (3) did the Dogon hear about the white dwarf companion of Sirius from a visiting European? Or, (4) was the French anthropologist mistaken and the Dogon in fact never had such a legend?
Why should it be hard for scientists to get science across? Some scientists, including some very good ones, tell me they’d love to popularize, but feel they lack talent in this area. Knowing and explaining, they say, are not the same thing. What’s the secret?
There’s only one, I think: don’t talk to the general audience as you would to your scientific colleagues. There are terms that convey your meaning instantly and accurately to fellow experts. You may parse these phrases every day in your professional work. But they do no more than mystify an audience of non-specialists. Use the simplest possible language. Above all, remember how it \vas before you yourself grasped whatever it is you’re explaining. Remember the misunderstandings that you almost fell into, and note them explicitly. Keep firmly in mind that there was a time when you didn’t understand any of this either. Recapitulate the first steps that led