Suppose the earth were a perfect sphere and you fitted a belt around its equator.
The belt would be 40 million meters long. If you now increased its length by a mere 5 meters, how high would it ride above the earth’s surface?
The answer, surprisingly, is 0.8 meters — well above the current limbo record.
1634 = 14 + 64 + 34 + 44
A pangram is a sentence that uses each letter of the alphabet exactly once:
CWM FJORD BANK GLYPHS VEXT QUIZ.
“Carved symbols in a mountain hollow and on the bank of a fjord irritated an eccentric person.” They’re a bit awkward in English, so here’s the same idea using numbers. Each of these (valid) equations uses the digits 1-9 exactly once:
42 × 138 = 5796
27 × 198 = 5346
39 × 186 = 7254
48 × 159 = 7632
28 × 157 = 4396
4 × 1738 = 6952
4 × 1963 = 7852
Even better: The numbers 3 and 51249876, between them, use all 9 digits — and so does their product, 153749628.
Imagine a large sheet of rice paper one-thousandth of an inch thick. Tear it in half and stack the pieces, then tear the stack in half and stack those, and so on. If you could do this 50 times in succession, how tall would the final stack be?
A. 0.6 inches
B. 22.84 feet
C. 17 million miles
Surprisingly, the answer is 17 million miles:
250 ply × 0.001 inches/ply
= 1.12589991 × 1012 inches
= 17,769,884.9 miles
In Gulliver’s Travels, Jonathan Swift describes two fictional moons of Mars:
They [the Laputan astronomers] have likewise discovered two lesser stars, or ‘satellites,’ which revolve about Mars, whereof the innermost is distant from the centre of the primary planet exactly three of his diameters, and the outermost five; the former revolves in the space of ten hours, and the latter in twenty-one and a half; so that the squares of their periodical times are very near in the same proportion with the cubes of their distance from the centre of Mars, which evidently shows them to be governed by the same law of gravitation, that influences the other heavenly bodies …
That was in 1726. A century and a half later, two Martian moons were discovered. Phobos and Deimos were in fact about 1.4 and 3.5 diameters from Mars’ center, and they revolved in 7.7 and 30.3 hours, respectively. Voltaire had made a similarly prescient guess in his romance Micromegas of 1752.
Fittingly, two craters on Deimos have been named Swift and Voltaire.
122 = 144
212 = 441
132 = 169
312 = 961
MIT mails its acceptance letters on 3/14 — “Pi Day.”
