October 27, 2000

Strange But True!

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?

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.”

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. 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. If we overheard extraterrestrials cracking a joke, would we laugh? Can humor cross species and worlds?

A. To “get” the joke we would obviously need to share a language with the ETs, which is tricky enough, says artificial intelligence researcher Kim Binsted, Ph.D., with I-Chara Inc., creator of humorous AI characters. “We’d also need to share some background knowledge — if the joke is about Betelguesian Cloud Dancers, and I’ve never been to Betelguese, I probably won’t get the reference.”

Even if our language and background knowledge match, we still might not laugh. Humor is based on incongruity and surprise, so we’d need to share with this alien some expectations about the way the universe works. A man slipping on a banana peel probably wouldn’t be funny to someone who had never experienced gravity.

Timing is vital to the success of a performed joke. But what if the alien is more plant than animal, cogitating slowly over thousands of years? By the time it gets to the punchline, we will have forgotten the set-up.

Finally, says Binsted, the joke won’t work if the social context is wrong. For example, we don’t laugh if we feel threatened. So, if the jokester is a 5-meter-long slug-like thing with pointy fangs and acidic saliva, the joke will probably fall flat.

“All this said, cognition and humor are closely linked. If we do meet any intelligent aliens, odds are they’ll have a sense of humor — even if we don’t get the joke.”

Previous columns:

• Strange But True!, 10-20-2000
• Strange But True!, 10-13-2000
• Strange But True!, 10-06-2000
• Strange But True!, 09-29-2000