Put a rock in the desert and wait a jillion years, and the blowing sand will make one of these for you. They’re also known as rock pedestals.
Oddities
Loopy
You can measure a circle’s circumference by “unrolling” it along a line, like this:
But note that the smaller circle unrolls at the same time … and it gives the same length. Clearly we could do the same thing with circles of any size. Do all circles have the same circumference?
Fathomless Genius
On Aug. 11, 1966, a fishing boat came upon a badly bruised man floating in the water off Brest, France, clutching an inflatable life raft. He identified himself as Josef Papp, a Hungarian-Canadian engineer, and claimed he had just bailed out of a jet-powered submarine that had crossed the Atlantic in 13 hours.
The media laughed at this, but Papp insisted he had built a cone-shaped sub in his garage that could reach 300 mph using the same principle as a supercavitating torpedo. He even wrote a book, The Fastest Submarine, to answer his critics … but somehow this failed to explain how the sub worked, or why plane tickets to France had been found in his pocket, or why a man matching his description had been seen boarding a plane to France hours earlier.
For what it’s worth, Papp did patent a number of other inventions, including a fuel mixture composed from inert noble gases. So maybe he was telling the truth.
Exception Paradox
If every rule has an exception, then there must be an exception to the rule that every rule has an exception.
Purple Rain
The sky isn’t blue. It’s actually violet, but a quirk of human vision makes us less sensitive to those wavelengths.
The Hard Way
In 1896, New Jersey clam diggers Frank Samuelsen and George Harbo decided to make a name for themselves by rowing across the Atlantic Ocean. On June 6 they set out from the Battery in an 18-foot oak rowboat with a compass, a sextant, and a copy of the Nautical Almanac. They reached England’s Isles of Scilly in 55 days, a record that still stands.
Ironically, on the way home their passenger steamer ran out of coal. The pair launched their boat and rowed back to New York.
The Eyes Have It
Decide which direction each of these men is looking in. Then cover their lower faces.
Little Boy Lost
In November 1890, 4-year-old Ottie Cline Powell was gathering firewood when he wandered away from his schoolhouse in Amherst County, Virginia. An extensive search couldn’t find him.
His body was found the following spring on the peak of Bluff Mountain in the Blue Ridge — 7 miles away, at an elevation of 3,372 feet.
Floating Saucers
This may be the first UFO photo ever taken. It’s half of a stereo photograph dating from 1871, showing a cigar-shaped ship over Mount Washington, N.H.
“Mystery airships” were floating ominously over America between 1896 and World War I, but neither the ships nor the witnesses had quite got the hang of things yet. In 1897 the Washington Times suggested that the dirigibles were “a reconnoitering party from Mars”; the Saint Louis Post-Dispatch agreed that “these may be visitors from Mars, fearful, at the last, of invading the planet they have been seeking.”
But other accounts said they were terrestrial airships piloted by mysterious humans. One of these supposedly told an Arkansas state senator that he was flying to Cuba to use his “Hotchkiss gun” to “kill Spaniards.” In Texas, witnesses told of meeting “five peculiarly dressed men” who had descended from the Lost Tribes of Israel; they had learned English from British explorer Hugh Willoughby’s ill-fated 1553 expedition to the North Pole.
Much of this is documented, but newspaper writers themselves were prone to practical jokes in that era, which makes the whole thing impossible to untangle. Plus, people seem to want to believe this stuff: In April 1897, hoaxers sent up a balloon made of tissue paper over Burlington, Iowa. The Des Moines Leader received reports that the ship had “red and green lights” and that “one reputable citizen swore he heard voices.” Oh well.
Nevermore
Seeing a red apple should increase your confidence that all ravens are black.
Why? Because the statement “All ravens are black” is logically equivalent to “All non-black things are non-ravens.” And seeing a red apple (or green grass) confirms this belief.
This is logically inescapable, even if it’s counterintuitive. It’s known as Hempel’s paradox.