Carl Sagan

This rainy winter morning is Carl Sagan's birthday, and you can't help wondering if the superstar of ''Cosmos'' will rumble about billions and billions of years, the Saganism that Johnny Carson mimics for a big laugh.

But no. Dr. Sagan just glances across the hotel room to a cosmically chocolate birthday cake, a gift from the Union of Concerned Scientists. Sagan seems nuarly as pleased with the cake as he would be with a gift-wrapped supernova. The reason he's pleased, he explains, is the same reason he did the hit ''Cosmos'' series on public television: ''The idea was to get across to people that science is a basically human enterprise, that it's not an activity of socially inept people in long white coats who live in ivory towers.''

Carl Sagan, astronomer, Pulitzer prize-winning writer as well as poet laureate of the planets, has probably done more than anyone in the United States today to popularize the humanity of science. A showman of ability, it's no accident that he's the most well-known scientist in the country today. Even the most abstract concepts he translates into vivid and understandable examples. He is creator and star of his 13-part public television series and author of the companion best-seller book ''Cosmos.'' And to produce these Carl Sagan rummages through his gorgeous attic of history, ransacking it for images, music, philosophy, writing, paintings, places, and events that will excite the eye and mind of the viewer into learning the concepts he's teaching. Shakespeare, Giotto's ''Adoration of the Magi,'' Thomas Huxley, the Book of Job, ''Alice in Wonderland,'' Vincent van Gogh, Sir Isaac Newton, Bach, Edgar Rice Burroughs, and the voices of humpback whales are among the hundreds of stimuli with which he bombards the viewer.

Sagan begins one episode with a giant closeup of an apple being split, cut up , baked in a pie in a huge oven, and emerging from a kitchen at Cambridge University, where the nature of the atom was first understood. He shows the viewer that ''if you want to make an apple pie from scratch you must first invent the universe.'' Or we may see him wind-swept at the prow of a ship, piloting us through the Aegean Sea and the 6th century Ionian concept of an ordered universe they call cosmos, the opposite of chaos.

In person he wears the familiar ''Cosmos'' working duds: the trademark turtleneck, this time navy blue with a blue and white microchecked shirt, open at the neck, worn over it. With it, a na y blazer, gray flannel pants. Dr. Sagan is one of the few media celebrities who appear very much in person as they doon the tube. The familiar, deep velour voice with its compelling rhythms and cadences is slightly less resonant, but his intensity is even more pronounced. Carl Sagan, live, blazes like the Pleiades with wonder at his subject. It is the sort of wonder that you connect with children who are learning about the world for the first time. The secret of Sagan's success may be that he shares that wonder, makes his viewers and readers feel it too.

''I think everybody isPqOn with that wonder,'' he says, ''and the society beats it out of you. That's why people say nostalgically, 'When I was little, I was interested in astronomy also.' And I think it happens like this: Youngsters who are slowly examining the world around them and wondering about it ask perfectly good questions, like 'Why is the grass green?' Because they can imagine it purple, or orange. Why should it be green?

''The adult who's answering the question is annoyed by the question. . . . There's something about the question which puts the adult on the defensive. The adult says 'Don't ask dumb questions. What color do you expect it to be?' Now when the child tries that a few more times - 'Why is the sky blue?' or 'Why is the moon round?' - and gets that response from the teacher, the child is being told 'Look, ask questions like this and adults will be mad at you. It's a better policy never to ask questions,' and suddenly the buLding young scientist has been turned off.

''Much later, when there's still some longing for those days when it was permissible to ask those questions, it turns out that these are excellent questions. The reasons the moon is round, the sky is blue go deeply into the nature of matter and the nature of gravity. . . . When the grownup child discovers that the questions are perfectly good questions, there is an enormous sense of loss that this wonder, this enthusiasm for understanding the world was turned off for no good reason. And I think it's a social tragedy that we prevent people from asking deep questions at an early age and remove them from making major contributions to science.''

There is still something boyish about Dr. Sagan, with his head of thick, shaggy black hair tumbling over very wide, quizzical brown eyes. When he was growing up in the Bensonhurst section of Brooklyn he wondered about life beyond the elevated railway on 86th Street and about the stars, ''twinkling and remote. I would ask older children and adults who would only reply, 'They're lights in the sky, kid.' ''

Sagan has written and said, ''I could see they were lights in the sky. But what were they? Just small hovering lamps? Whatever for?'' When he got up his courage and went to the local library to ask for a book on stars, the librarian handed him one full of pictures of stars like Lana Turner and Tyrone Power. No, that's not what I want, he complained, until she smiled and found a book on the right kind of stars. He's been answering his own star questions ever since, as author, co-author, or editor of more than 12 books, including ''The Cosmic Connection,'' ''The Dragons of Eden,'' ''Broca's Brain'' and ''Intelligent Life in the Universe.'

Hewhizzed through college himself. At 16 he attended the University of Chicago on a scholarship, at 25 he left with a PhD in astronomy and astrophysics. He now is director of the Laboratory for Planetary Studies and the David Duncan professor of astronomy and space sciences at Cornell University. He attributes his Renaissance-man attitude toward science, art, and the humanities to the demand for a broad general education under the late Rober Maynard Hutchins, then president of the University of Chicago. Sagan, who had always known he wanted to be only a scientist, was forced to learn about subjects he'd never even heard about before, things like cultural anthropology, Ruswian novels, music before Mozart. He loved it all, and it became part of the fabric of his life.

Dr. Sagan criticizes today's culture as a whole for ''tending to isolate and separate. I think nature is a continuum and for convenience people do things, put things into separate pigeonholes, and they forget that those pigeonholes are entirely made byPt xo. And because there are a whole lot of things to know, people tend to specialize, concentrate on one thing and figure the other things are for someone else. I think that's very dangerous. I think it's dangerous, for example, for politicians not to know science, and for scientists not to know politics.''

That's why he had flown into Washington on his birthday for a breakfast meeting with reporters and talks on Capitol Hill. As a spokesman for the Union of Concerned Scientists, he was here to talk about the anxiety of the nations' scientists over the growing threat of a nuclear war. A dark silence settled over the breakfast meeting after Sagan vividly described the ''litany of horrors'' that would follow any nuclear strike, outlining with all the force of his ''Cosmos'' appeal the specific horrors in its wake, from radiation to plague, the partial destruction of the ozone layer, the resultant cooling of the earth with consequences so great they could not be estimated. ''Nothing is as important as preventing the destruction of the human species,'' he warned.

Although Dr. Sagan talks with authority about some of the gravest and most complex scientific subjects, he also knows how to communicate in the simplest terms. This astronomer, who has received from 6,000 to 7,000 letters from fans about his ''Cosmos'' series, says even moppets watch him.

Perhaps a hundred people have written him to say that their children, 18 months to two years old, insisted on watching ''Cosmos.'' ''Now they (adults) can't understand it,'' says Sagan. ''There's no possibility they can understand what I'm saying. But there's something about the visuals and the music. Isn't it amazing that two-year-olds recognize there's something significant about discussing the universe? I mean, look how deeply it's built into human beings, to be interested. . . .

''The experience has made it very clear that there's a vast, untapped, unsatisfied interest in things of the mind in this country. It's not being satisfied. Is it the fault of commercial television? Sure. They're interested in short-term profit, of course. The idea is to get the lowest common denominator with the least effort to get the largest audience. Then you get the ancient parts of the brain, that are concerned with sex and violence. The modern parts . . . that are involved with thinking, you bypass because it takes more effort to interest them.''

The celebrity that has come to Sagan through ''Cosmos,'' the thousands of letters, the autograph-seekers in airports and restaurants, the fans who call him from Australia on his birthday, all that stardust, interests him as a phenomenon, just as he's interested in the great red spot of Jupiter as a phenomenon. And it pleases him, but he says it doesn't turn his head, as it would a young rock star suddenly famous overnight. He doesn't take it personally. ''I'm extremely flattered that people recognize me, and still more delighted that they recognize or remember points I've been trying to make. I'll tell you what I think is behind it:

''I think people are much smarter than they're generally given credit for, for they're interested in deep questions, such as questions of origins. And the school system and media and societal conventions don't encourage them. The general level of intellectual challenge is very low. But humans are smart and curious and creative and they hunger for such challenges. So when by luck somebody can present things of this sort, people are grateful.

''In many cases people didn't even know that they hungered for it till they came upon it. And suddenly there's a response. . . . So people personalize it because there's a face and a voice that presents it, but anybody can present hat kind of intellectual satisfaction to people every day. So I don't think it's anything deeply personal about me.'' In addition to a sense of his own limitations, Sagan points out, there is something else. He says this in scientific nargon, but there is great affection in his voice: ''because of Annie I have a lot of reality testing.''

Annie is his wife, Ann Druyan, one of his co-writers on the TV series and the woman to whom he has dedicated the book ''Cosmos,'' with these words: ''In the vastness of space and the immensity of time, it is my joy to share a planet and an epoch with Annie.''

It is a twinkling paradox that Dr. Sagan, the embodiment of the rational scientific man, is also one of the true romantics. He and Annie met at a party given by a mutual friend; ''I think I fell in love instantly,'' he reminisces, ''although it took me two years to recognize what it was.'' Sagan, who has been married twice before, talks briefly about what is important in marriage. ''I'm not sure this is amenable to scientific analysis,'' he smiles. ''I think you have to have mutual respect. That counts a lot. But falling hopelessly in love helps. . . .'' Can this be the astrophysicist who rhapsodizes over cryogenic superconducting electrovores with neutron crystal dense packing and module starminers? ''Well, yeah, I'm in favor of love. It's just not so easy to come by. If you're lucky enough to tumble into it, I certainly recommend it.''

They are rarely apart, he says. Ann Druyan, a writer who is not introduced as Mrs. Sagan, is with him on this trip to Washington. She is articulate and informed. She also follows his every word with huge, melting brown eyes in a heart-shaped face. A pretty young woman with long, curling dark hair, she speaks softly and dresses softly: a quiet beige knit outfit.

Dr. Sagan, who has three children from his previous marriages, says the most important thing to teach children is ''that they're a part of the human community and that there is an obligation to others. . . . We have serious obligations (to give something to future generations), not just to make a living and not just to be happy. That's not enough.'' One of his grown children is a computer programmer, another a writer-artist; the third is too young for a career.

Sagan and his wife have written a movie treatment for a feature film called ''Contact,'' about the first contact with extraterrestrial intelligences. ''I'm sworn to secrecy about much of the plot,'' he says. Like a weathercaster he predicts there is a 90 percent probability of the film being made by Columbia Pictures. And he adds that the leading character is a scientist - a woman scientist. At this moment he's writing the novel on which the film will be based and is having a lot of fun with it. ''One of my objectives is to portray in a feature film context the possibility of doing 'Cosmos' type effects on a large screen. That's very appealing to me. It's never been done. And also to get across the idea of scientists as people, not as cardboard cutouts, or malevolent monsters.''

There is something of the stern moralist in Dr. Sagan as well as of the impassioned teacher. This scientific authority on the stars'sharply condemns astrologers and astrology, describing it as a pseudo-science practiced for profit by those who pander to the public's gullibility:

''It turns out that astrology is, at the very least, unproved, and that it's possible to go further and say it's a flimflam. It's a bamboozle. That it is propagated simply to make money for the astrologers and to deceive a credulous public.

''The actual situation is that we are hooked up to the universe, but we're hooked up in much more profound ways than the cozy little fantasies of the astrologers can imagine. For example, we are made of star stuff! The atoms in our bodies are cooked in the insides of stars. It's not that a star rising has a mystical influence on the moment of my birth. By the way, why my birth, rather than my conception? It's the atoms that are calcium in my teeth and the carbon in my genes that were made in stars billions of years ago in time, thousands of light years away in space. That's a just astonishing fact. It's true that it doesn't help me to decide whether to slay at home tonight or to go out. But maybe we shouldn't turn to astrology columns to make those decisions for our lives.''

The Carl Sagan who says ''Bah, humbug!'' to astrology and horoscopes is concerned with the root of its apparent appeal, a deep human need. ''I think people's interest in astrology comes from the same source as their interest in astronomy and science in general. (It's) the idea that you are connected with the cosmos, that you have some cosmic significance, that you count. That's a desire and wish of everyone. And the pursuit of that interest can lead straight to science. But if science isn't available, if you're growing up and there are copies of American Astrologist around and no copies of Scientific American, then what you know about is astrology. And you make do with it to satisfy your scientific interests and longings. It is only when the science is in default that the pseudo-science succeeds.''

When Carl Sagan was growing up, it was not just Scientific American but a variety of other unexpected things that shaped his interest: The kid who played stickball on the streets collected Classic Comics, Captain Marvel, Superman, fantasized about Edgar Rice Burroughs's Martian books, loved Disney's ''Fantasia'' (it opened up the world of mythology to him), and found the ''World of Tomorrow'' scientific exhibit at the 1939 World's Fair a turning point in his life. He also remembers that at home, ''We started out poor and got to be middle class.''

His mother was born in the US, his father was a Russian immigrant who went from garment-cutter to factory manager. Sagan says, ''I look back on my childhood with enormous nostalgia, which I think means that I had a happy childhood.''

Today he lists among his favorite things listening to music -- from Jefferson Starship to a Bach partita for unaccompanied violin, Schonberg, Indian music, Louis Armstrong's ''Long Horn Blues.'' He also enjoys reading, traveling, going for long walks with Annie. ''The thing I like most when I have spare time is to do anything with Annie.'' And of course he enjoys, as he puts it, ''doing science.''

''One of my great satisfactions recently, getting back to 'Cosmos,' is doing research on the outer solar system using data from the Voyager spacecraft.''

Perhaps because he is the most famous stargazer in the country, there are inevitably criticisms of him: His critics say he is arrogant and that he may be famous but does not have the hallmark of a true scientist because he doesn't concentrate on the slow, long-term research that results in scientific breakthroughs.

He nods. He's heard it all before and thinks it's up to his critics to justify such remarks. ''I don't think I have to deny them.'' Those who accuse him of arrogance would be surprised to find that he admits ''there has always been an element of shyness'' in his personality and that he doesn't consider himself an extrovert. He says it's the enthusiasm, the excitement of teaching, via ''Cosmos'' that give him the assurance viewers see on the screen.''

But on the question of dedication to one or another project,'' he says, there may be projects lhat are small but have ''occupied me for 10 or 20 years. The laboratory production of complex organic molecules, (Which I mentioned) in the context of the clouds of Titan. I've been working on that since 1965. Or the question of wind-blown sand on planetary surfaces. I've been working on that since 1967. Still working on it.''

That criticism, he suggests, may come from his high profile: ''Because there is this tendency to compartmentalize people, and because my public side is the most visible, there is a tendency to see the public side and forget that I'm a working scientist. And always have been. And I understand the dynamics of what that is. It's not malice. It's inattention.''