The Cosmos

When I was little, I lived in a section of Brooklyn in the City of New York. I knew my immediate neighborhood intimately, every apartment building, backyard, empty lot, and elm tree. I knew where my friends lived. But more than a few blocks away, north of the noisy automobile traffic on 86th Street, was a strange unknown territory, off-limits to my wanderings. It could have been Mars for all I knew.

Even with an early bedtime, in winter you could sometimes see the stars. I would look at them, twinkling and remote, and wonder what they were. I would ask older children and adults, who would only reply, "They're lights in the sky, kid." I could see they were lights in the sky. But what were they? Just small hovering lamps? Whatever for? There had to be some answer.

As soon as I was old enough, my parents gave me my first library card. Immediately, I asked the librarian for something on stars. She returned with a picture book displaying pictures of men and women with names like Clark Gable and Jean Harlow. I complained, and for some reason then strange to me, she smiled and found another book—the right kind of book. I opened it in excitement and read until I found it. The book said something astonishing, a very big thought. It said that the stars were suns, only very far away. The Sun was a star, but close up. Imagine that you took the Sun and moved it so far away that it was just a tiny point of light. How far away would you have to move it? I did not have any idea of angular size. I was ignorant of the inverse square law for light propagation. I did not have the slightest idea of calculating the distance to the stars. But I could tell that if the stars were suns, they had to be very far away—farther away than 85th Street, farther away than Manhattan, farther away, probably, than New Jersey. The Cosmos was much bigger than I had guessed.

Later I read another astonishing fact. The Earth, which includes Brooklyn, is a planet, and it goes around the Sun. There are other planets. They also go around the Sun; some are closer to it and some are farther away. But the planets do not shine by their own light, as the Sun does. They merely reflect light from the Sun. If you were a great distance away, you would not see the Earth and the other planets at all? they would be only faint luminous points, lost in the glare of the Sun. Well, then, I thought, it stood to reason that the other stars must have planets too, ones we have not yet detected, and some of those other planets should have life (why not?), a kind of life probably different from life as we know it, life in Brooklyn. So I decided I would be an astronomer, learn about the stars and planets and, if I could, go and visit them.

It has been my immense good fortune to have parents and some teachers who encouraged this odd ambition and to live in this time, the first moment in human history when we are, in fact, visiting other worlds and engaging in a deep exploration of the Cosmos. If I had been born in a much earlier age, no matter how great my dedication, I would not have known that there were other suns and other worlds. This is one of the great secrets wrested from Nature through a million years of patient observation and courageous thinking by our ancestors.

What are stars? Such questions are as natural as an infant's smile. We have always asked them. What is different about our time is that at last we know some of the answers. Books and libraries provide a ready means for finding out what those answers are.