Word: earths
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Dates: during 1990-1999
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Hubble and his assistant, Milton Humason, began measuring the distances to these receding nebulae and found what is now known as Hubble's Law: the farther away a galaxy is from Earth, the faster it's racing away. Could it be that the universe as a whole is rapidly expanding? That conclusion was extraordinary, almost mind-blowing, yet seemed inescapable...
Hubble's last great contribution to astronomy was a central role in the design and construction of the Hale Telescope on Palomar Mountain. Four times as powerful as the Hooker, the Hale would be the largest telescope on Earth for four decades. It would have been even longer, but its completion was interrupted by World War II. So was Hubble's career. The ex-major signed on as head of ballistics at Aberdeen Proving Ground in Maryland. (At one point the eminent astronomer spent an afternoon test-firing bazookas, at great personal risk, to pinpoint a design flaw...
...this concrete is to imagine that on some far planet (Mars, let's say) all the symbols used to write math books happen--by some amazing coincidence--to look like our numerals 0 through 9. Thus when Martians discuss in their textbooks a certain famous discovery that we on Earth attribute to Euclid and that we would express as follows: "There are infinitely many prime numbers," what they write down turns out to look like this: "84453298445087 87863070005766619463864545067111." To us it looks like one big 46-digit number. To Martians, however, it is not a number...
...from such familiar notions as "prime number," "odd number" and so forth. Thus earthbound number theorists could, with their standard tools, tackle such questions as, "Which numbers are M.P. numbers, and which are not?" for example, or "Are there infinitely many non-M.P. numbers?" Advanced math textbooks--on Earth, and in principle on Mars as well--might have whole chapters about M.P. numbers...
When he first proposed his heretical ideas early in the century, many geologists treated this German meteorologist as if he were a member of the Flat Earth Society. Convinced that the continents were anchored firmly in place, geologists dismissed as preposterous his theory that the earth's major land masses had once been huddled together in a single supercontinent, which he called Pangaea (Greek for "whole earth"), then began slowly drifting apart. Wegener had plenty of evidence, ranging from the jigsaw-like fit of the continents to the discovery of matching fossils on opposite sides of oceans, but he couldn...