The Visby Lenses

In 1997, three scientists examined 10 rock crystal lenses discovered in a Viking grave on Sweden’s Gotland Island. Made in the 12th century, the lenses had been thought to be simple ornaments, but examination showed they had been crafted with the ideal focusing lens shape 500 years before Descartes could calculate it mathematically.

“It seems that the elliptical lens design was invented much earlier that we thought and then the knowledge was lost,” researcher Olaf Schmidt told the BBC. Scientists speculate that the lenses were used to start fires or perhaps even to form a crude telescope.

Who made them? Not Vikings — probably a group of craftsmen in Byzantium or Eastern Europe, possibly even a single talented artisan. Whoever it was, he knew even more about applied optics than scientists at the time.

| Oddities · Science & Math

Infinite Egress

http://commons.wikimedia.org/wiki/File:Mort.jpg

Leinbach had discovered a proof that there really is no death. It is beyond question, he had declared, that not only at the moment of drowning, but at all the moments of death of any nature, one lives over again his past life with a rapidity inconceivable to others. This remembered life must also have a last moment, and this last moment its own last moment, and so on, and hence, dying is itself eternity, and hence, in accordance with the theory of limits, one may approach death but can never reach it.

— Arthur Schnitzler, Flight Into Darkness, 1931

| Death · Science & Math

Con Proofing

John von Neumann suggested a way to flip a suspect coin and produce fair results: Flip it twice.

Tails-heads decides in favor of one party, heads-tails the other. The two results are equally likely, even with a biased coin. (If it comes up heads-heads or tails-tails, flip it twice again.)

| Science & Math

In a Word

lethologica
n. the inability to remember a word

In her 1989 textbook Cognition, psychologist Margaret Matlin notes that most people who read the definitions below find it hard to summon the words they refer to. How many can you name? I’ll give the answers tomorrow.

  1. An absolute ruler, a tyrant.
  2. A stone having a cavity lined with crystals.
  3. A great circle of the earth passing through the geographic poles and any given point on the earth’s surface.
  4. Worthy of respect or reverence by reason of age and dignity.
  5. Shedding leaves each year, as opposed to evergreen.
  6. A person appointed to act as a substitute for another.
  7. Five offspring born at a single birth.
  8. A special quality of leadership that captures the popular imagination and inspires unswerving allegiance.
  9. The red coloring matter of the red blood corpuscles.
  10. Flying reptile that was extinct at the end of the Mesozoic era.
  11. A spring from which hot water, steam, or mud gushes out at intervals, found in Yellowstone National Park.
  12. The second stomach of a bird, which has thick, muscular walls.
  13. The green coloring matter found in plants.
  14. The long-haired wild ox of central Asia, often domesticated as a beast of burden.
  15. The art of speaking in such a way that the voice seems to come from another place.
Click for Answer
| Language · Science & Math

The Royal Scam

Sir Walter Raleigh once made a wager with Elizabeth that he could weigh the smoke from his tobacco pipe.

When she accepted, he weighed his tobacco, smoked the pipe, and then weighed the ashes that remained.

The queen paid him. “I have seen many a man turn his gold into smoke,” she said, “but you are the first who has turned his smoke into gold.”

| History · Science & Math

Unquote

“Moreover, the satellites of Jupiter are invisible to the naked eye, and therefore can exercise no influence over the Earth, and therefore would be useless, and therefore do not exist.” — Astronomer Francesco Sizzi, on Galileo’s claim to have seen the moons of Jupiter

| Quotations · Religion · Science & Math

Timeless Reason

In an 1849 letter to his sister, Lewis Carroll asks which is more accurate, a clock that is right once a year or one that has stopped altogether. The stopped clock is more accurate, he says–because it’s correct twice a day.

You might go on to ask, ‘How am I to know when eight o’clock does come? My clock will not tell me.’ Be patient, reader: you know that when eight o’clock comes your clock is right; very good; then your rule is this: keep your eye fixed on your clock, and the very moment it is right it will be eight o’clock.

“‘But–‘ you say. There, that’ll do, reader; the more you argue the farther you get from the point, so it will be as well to stop.”

| Literature · Science & Math