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Ballooning produced a new, and wholly unexpected, vision of the earth. It had been imagined that it would reveal the secrets of the heavens above, but in fact it showed the secrets of the world beneath. The early aeronauts suddenly saw the earth as a giant organism, mysteriously patterned and unfolding, like a living…
It is possible to measure how far away from us each galaxy is. How? How, for that matter, do we know how far away anything in the universe is? For nearby stars the best method uses something called 'parallax'. Hold your finger up in front of your face and look at it with your left eye closed. Now open your left eye…
The mathematician Freeman Dyson, of the Institute for Advanced Study, offers a scheme in which the planet Jupiter is broken down piece by piece, transported to the distance of the Earth from the Sun, and reconstructed into a spherical shell – a swarm of individual fragments revolving about the Sun. The advantage of…
There is a place with four suns in the sky – red, white, blue, and yellow; two of them are so close together that they touch, and star-stuff flows between them. I know of a world with a million moons. I know of a sun the size of the Earth – and made of diamond. There are atomic nuclei a mile across that rotate thirty…
It is possible to speculate on the very distant future of advanced civilizations. We can imagine such societies in excellent harmony with their environments, their biology, and the vagaries of their politics, so that they enjoy extraordinarily long lifetimes. Communications would long have been established with many…
On the title page of this chapter is shown the message. It is etched on a 6-inch by 9-inch gold-anodized aluminum plate, attached to the antenna support struts of Pioneer 10. The expected erosion rate in interstellar space is sufficiently small that this message should remain intact for hundreds of millions of years…
The earth's atmosphere is an imperfect window on the universe. Electromagnetic waves in the optical part of the spectrum (that is, waves longer than X rays and shorter than radio waves) penetrate to the surface of the earth only in a few narrow spectral bands. The widest of the transmitted bands corresponds roughly to…
Calculus is one of the most important parts of mathematics. It is fundamental to all of modern science. How could one part of mathematics be of such central importance? It is because calculus gives us the tools to study rates of change and motion. All analytical subjects, from biology to physics to chemistry to…
The way we discovered how species arise resembles the way astronomers discovered how stars “evolve” over time. Both processes occur too slowly for us to see them happening over our lifetime. But we can still understand how they work by finding snapshots of the process at different evolutionary stages and putting these…
Man, being the servant and interpreter of Nature, can do and understand so much and so much only as he has observed in fact or in thought of the course of nature. Beyond this he neither knows anything nor can do anything.
We lay and looked up at the sky and the millions of stars that blazed in darkness. The night was so still that we could hear the buoy on the ledges out beyond the mouth of the bay. Once or twice a word spoken by someone on the far shore was carried across the clear air. A few lights burned in the cottages. Otherwise…
After an evening of talk, perhaps about the fringes of knowledge, or some new possibility of climbing inside the minds and senses of animals, we would go out on the lawn, where we took turns at an amusing little astronomical rite. We searched until we found, with or without glasses, the faint, heavenly spot of…
Water is so uniquely favorable to life as we know it, it is hard to imagine life without it. Where did it come from, this planetary wrap of fluid, this liquidy bower? A standard story is that the heat of the young Earth drove hydrogen and oxygen out of chemical combination in minerals like mica, and these atoms then…
And so they say that Uncle Paul knows any number of stories. He investigates, he observes for himself. When he walks in his garden he is seen now and then to stop before the hive, around which the bees are humming, or under the elder bush, from which the little flowers fall softly, like flakes of snow; sometimes he…
A more sophisticated consequence of omphalogical reasoning would be that stars whose distance from us is more than a few thousand light years must have been created with ready-made light beams stretching almost all the way to us - otherwise we wouldn't be able to see them until the distant future!
Sun's nature as revealed by modern science far more wonderful: no mere angels or gold coin, but an enormous sphere into which a million Earths could be packed, in the core of which the hidden nuclei of atoms are being jammed together, hydrogen transfigured into helium, the energy latent in hydrogen for billions of…
Try to imagine what the electric and magnetic fields look like at present in the space of this lecture room. First of all, there is a steady magnetic field; it comes from the currents in the interior of the earth - that is, the earth's steady magnetic field. Then there are some irregular, nearly static electric fields…
Greek mathematics was a brilliant step forward. Greek science, on the other hand - its first steps rudimentary and often uninformed by experiment - was riddled with error. Despite the fact that we cannot see in pitch darkness, they believed that vision depends on a kind of radar that emanates from the eye, bounces off…
...the order of the Universe is not an assumption; it's an observed fact. We detect the light from distant quasars only because the laws of electromagnetism are the same ten billion light years away as here. The spectra of those quasars are recognizable only because the same chemical elements are present there as…
In 1967, British scientists found a much nearer intense radio source turning on and off with astonishing precision, its period constant to ten or more significant figures. What was it? Their first thought was that it was a message intended for us, or maybe an interstellar navigation and timing beacon for spacecraft…