# Doomsday Clock

Every issue of the Bulletin of the Atomic Scientists since 1947 has displayed a clock face on its cover, symbolizing the world’s proximity to nuclear war (in the judgment of the bulletin’s board of directors).

At its most dire, the clock stood at two minutes to midnight in 1953, when the United States and the Soviet Union tested thermonuclear devices within nine months of one another. Thirty-eight years later, when the superpowers signed the START treaty in 1991, the clock reached 17 minutes to midnight, its most hopeful position to date.

That doesn’t mean we’re making progress. Today it stands at 7 minutes to midnight — which is just where it started 59 years ago.

# Bullseye

0.999… is the same as 1. Not just very close, but precisely identical:

a = 0.999…
10a = 9.999…
10aa = 9.999… – 0.999…
9a = 9
a = 1

There’s no trick here. It’s just a mathematical fact that most people find deeply counterintuitive.

# One, Three, Five …

In English, every odd number contains the letter e.

# The Feynman Point

Between the 762nd and 767th decimal places of pi there are six 9s in a row.

It’s called the Feynman point, because physicist Richard Feynman said he’d like to recite 761 digits and end with “… nine, nine, nine, nine, nine, nine, and so on.”

# More Mathematical Coincidences

32 + 42 = 52

And:

33 + 43 + 53 = 63

# A Mathematical Coincidence

2646798 = 21 + 62 + 43 + 64 + 75 + 96 + 87

The world’s slowest science experiment is the “pitch drop experiment” at the University of Queensland. In 1927, physics professor Thomas Parnell poured some pitch into a funnel to see how long it would take to drip out. Pitch is pretty viscous: When Parnell died in 1948, only two drops had fallen.

The experiment is still going on. The eighth drop fell on Nov. 28, 2000, allowing experimenters to calculate that the pitch has a viscosity about 100 billion times that of water.

# Faces of a Pandemic

Famous people with HIV:

• Isaac Asimov
• Roy Cohn
• Eazy-E
• Michel Foucault
• Liberace
• Greg Louganis
• Robert Mapplethorpe
• Rudolph Nureyev
• Anthony Perkins

This is a jaglion, a cross between a jaguar and a lion. Big cats interbreed pretty easily, which makes for some confusing nomenclature.

Cross a lion with a tiger and you get a liger or a tigon, depending on the parents’ sexes. Cross a leopard with a jaguar and you’ll get a jagulep or a lepjag. And if you cross a puma with a leopard you get the magnificently named pumapard.

You can even make hybrids of your hybrids. Cross your new jagulep with a lion you’ll have a lijagulep. Keep going and eventually you can make liards, jaguatigers, doglas, leotigs, tigards, tiguars, and liguars.

And theoretically, if you crossed a jaguar with a tigress … you’d get a jagger. Hmmm.

# Diophantus’ Age

No one knows much about Diophantus, the Greek mathematician, but in the sixth century a math puzzle purported to give his epitaph:

“This tomb holds Diophantus. Ah, what a marvel! And the tomb tells scientifically the measure of his life. God vouchsafed that he should be a boy for the sixth part of his life; when a twelfth was added, his cheeks acquired a beard; He kindled for him the light of marriage after a seventh, and in the fifth year after his marriage He granted him a son. Alas! late-begotten and miserable child, when he had reached the measure of half his father’s [total] life, the chill grave took him. After consoling his grief by this science of numbers for four years, he reached the end of his life.”

At what age did he die?