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Consider the game of Chess. Typically it's played with a collection of Chess pieces on a chessboard consisting of black and white squares. We can all agree, I think, that these are indeed real-world objects. Moreover, the game involves a set of rules specifying how the pieces can move, what constitutes a legal…
After a while I noticed that the sun and all the stars in his neighborhood were ruddy. Those at the opposite pole of the heaven were of an icy blue. The explanation of this strange phenomenon flashed upon me. I was still traveling, and traveling so fast that light itself was not wholly indifferent to my passage. The…
The universe is a dark forest. Every civilization is an armed hunter stalking through the trees like a ghost, gently pushing aside branches that block the path and trying to tread without sound. Even breathing is done with care. The hunter has to be careful, because everywhere in the forest are stealthy hunters like…
The human capacity for compassion is not a reflex that is triggered automatically by the presence of another living thing. As we shall see in chapter 9, though people in all cultures can react sympathetically to kin, friends, and babies, they tend to hold back when it comes to larger circles of neighbors, strangers…
The breathtaking advance of scientific discovery has the unknown on the run. Not so long ago, the Creation was 8,000 years old and Heaven hovered a few thousand miles above our heads. Now Earth is 4.5 billion years old and the observable Universe spans 92 billion light years. Pick any scientific field and the story is…
The painter is standing a little back from his canvas [1]. He is glancing at his model; perhaps he is considering whether to add some finishing touch, though it is also possible that the first stroke has not yet been made. The arm holding the brush is bent to the left, towards the palette; it is motionless, for an…
This is an infinitely marvelous and beautiful universe which we are privileged to inhabit. Look inward to the molecules of life and the heart of the atom, or outward to moon, sun, planets, stars, the Orion Nebula where new suns and worlds are coming into being even as you watch, the Andromeda Nebula which is actually…
Name any event in history and you will find a star out there whose light gives you a glimpse of something happening during the year of that event. Provided you are not a very young child, somewhere up in the night sky you can find your personal birth star. Its light is a thermonuclear glow that heralds the year of…
the colours that we finally think we see are labels used for convenience by the brain. I used to be disappointed when I saw 'false colour' images, say, satellite photographs of earth, or computer-constructed images of deep space. The caption tells us that the colours are arbitrary codes, say, for different types of…
Piet Hut, another Dutch astronomer fifty years younger than Jan Oort, decided to take seriously the possibility that comet showers are periodic. If they are periodic, the theory that they are caused by the random passing-by of alien stars cannot be right. If showers are periodic, they must be explained by a different…
So numerous are the objects which meet our view in the heavens, that we cannot imagine a point of space where some light would not strike the eye;—innumerable stars, thousands of double and multiple systems, clusters in one blaze with their tens of thousands of stars, and the nebulae amazing us by the strangeness of…
Twinkle, twinkle little star. I don't wonder what you are, For by spectroscopic ken I know that you are hydrogen.
Science’s contributions to the spread of disbelief is the least controversial segment of the virtuous cycle for which I am arguing in seventeenth-century Europe. For science’s methods are clearly troublesome for religion. The devout, to begin with, are not wont to view their precepts merely as propositions to be…
In summary, the circumstellar shells of Dyson civilizations-at temperatures ~300 degrees K and radii ~1 a.u.--can be detected with existing telescopes and state-of-the-art infrared detectors in the 8-13-u window out to distances of several hundred parsecs. But discrimination of Dyson civilizations from naturally…
As to your reasoning of the inconvenience that a centre would become further removed from another centre than from the circumference of his own globe, though centres are of the same species while the centre and circumference are of contrary nature and should therefore be furthest removed from one another, I reply as…
figure out how to live with high technology, how to avoid nuclear war, then tehre are at this moment a million advanced civilizations in the Milky Way. This place was built to help get us through this dangerous time. it would be good to know if there are other civilizations out there, if their United Nations have…
Imagine the history of the galaxy with respect to extraterrestrial intelligence. Very early there were only first generation stars, no heavy metals and therefore no possibility of life, much less intelligence. That's Stage One. In Stage Two planets with heavy metals form from the starstuff processed in the previous…
The history of physics is littered with unrealized grand experiments: old blueprints buried in file drawers, half-built machinery packed in crates, excavated earth filled with pooling rainwater—the detritus of Big Science. As the frontier of human knowledge pushes forward, so, too, does the cost and the complexity of…
Behind every man now alive stand thirty ghosts, for that is the ratio by which the dead outnumber the living. Since the dawn of time, roughly a hundred billion human beings have walked the planet Earth. Now this is an interesting number, for by a curious coincidence there are approximately a hundred billion stars in…
However, the subject need not be an esoteric one for a gedankenexperiment to be fruitful. My own favorite is Galileo’s proof that, contrary to Aristotle’s view, objects of different mass fall in a vacuum with the same acceleration. One might think that a real experiment needs to be conducted to test that hypothesis…