Hair raising: Stop smiling and run!

Q. Oh, neat! You're outdoors on a lookout platform at Sequoia National Park when your long hair starts frizzing out like a halo, standing straight up on top. Your brother aims his camera: "Smile..." Should you? ­A. Steiglitz

 A. Five minutes after the above woman had her photo snapped and left, a lightning strike to the platform killed one person and injured seven, say David Halliday et al. in Fundamentals of Physics. The overhead cloud system (with much visible blue sky) had created a strong electric field near the woman's head, and many of her hair strands had extended upward along the field. From her smiling, she was clearly unaware of the danger, but if this happens to you, "You had better run for shelter– not pose for a snapshot."

Q. Will AC (alternating current, e.g. wall outlets) or DC (direct current, e.g. batteries) kill you faster? ­ D. Halliday

 A. This debate raged as part of the 1880s "battle of the currents," with Thomas Edison on one side boosting his new first DC power plant, and engineer William Stanley boosting his even newer AC power plant, says James D. Livingston in Driving Force: The Natural Magic of Magnets.

AC's big advantage is its transformability into higher or lower voltages, but it also got the rap of being more dangerous. Safety critic Harold Brown did a demo where a dog survived 1,000 volts DC, but died when subjected to 300 volts AC. "But that's a small dog, not a human," AC boosters countered, so Brown answered by stepping up his demos to include more human-sized calves and even a horse.

Bring on George Westinghouse, still maintaining AC wasn't more dangerous, until Brown challenged him to a duel by electricity: "Brown would take DC through his body and Westinghouse would take AC, at gradually increasing voltages until one cried 'enough' and admitted he was wrong (or died and proved it!). Westinghouse declined the offer."

Watching all this were New York State officials, who soon introduced the first electric chair– an AC chair.

Actually, says Livingston, both types of current can be deadly depending on how the power source is constructed and how the power is delivered to the body.

Q. What's really weird about human sex? ­W. Masters and V. Johnson

A. Forget the fringe stuff– the "main course" itself is pretty weird. For starters, we humans don't do it like other primates, preferring to keep our lovemaking private, says University of California physiologist Jared Diamond in Why Is Sex Fun? The Evolution of Human Sexuality. That's pretty strange for a "social" species.

Moreover, the woman's infertility– whether due to being pregnant, post-menopausal or at the wrong time of the month– doesn't stop her or him. Fact is, she rarely even has a good idea if she's fertile at any particular time or not, and certainly doesn't advertise it through distinctive smells, colors, sounds as do other mammals. ("Those disgusting humans," one can imagine a dog saying, "have it any day of the month.")

Then there's her rather unique menopause: Virtually no other mammal has this, says Diamond.

And as for the male, what's the point of such an unnecessarily large organ, exceeding that of a gorilla?

Finally, why do men usually or at least often stay with the women they impregnate to help raise the children? In this, too, we among mammals are unique– and uniquely lucky, many proud Dads might add.

Q. We all know what can happen if an asteroid a mile or two wide hits the Earth (R.I.P. the dinosaurs). What if it hits the moon? ­N. Armstrong

A. You'd see a bright flash from a night Moon, maybe even from a daytime Moon, lasting a few minutes before cooling to invisibility, says Yale physicist Bradley E. Schaefer. The crater would be moderate-sized, maybe 100 miles across. Such hits are rarer than on Earth (bigger, stronger gravity), occurring every half billion years or so.

The crater would spew out "rays," or streaky splash- marks toward the bull's eye– seen in an amateur telescope.

But on Earth, the biggest event would come from the rocks splattered off the Moon by the impact, that then enter our atmosphere as meteors. Some small fraction would make it down to Earth as Moon rocks. About a dozen of these from past hits have been found, sent here exactly this way.

Following impact, it would take about a week for the debris to arrive, then megaspectacular is the word for the ensuing meteor show. "I went to Tunisia for the November '99 Leonids, so I know what a mere spectacular superstorm is like! This will last another week or so and the sky will be filled every second with perhaps thousands of meteors!

"Fortunately, I know of no other effects from an asteroid impact on the Moon."

Send STRANGE questions to brothers Bill and Rich at