Ringers: Tree's age easy to gauge


Q. Along the seashore you and your gang discover an old Viking longship buried in mud. How might you ever date the age of the vessel? Clue: The ship is wood and wood means trees, so think dendrochronology. –L. Erickson

 A. Trees have annual rings visible across the diameter of the trunk, with the tree putting on more growth in some seasons than others, says Richard Dawkins in The Ancestor's Tale. So by counting all the growth rings, you can gauge the age of the tree quite precisely.

For instance, the enormous General Sherman sequoia tree in California– over 30 meters around, 80 meters tall and weighing 1260 tonnes– is probably over 3000 years old. A dendrochronological count of its rings would tell its age to within a few years, though the tree would need to be cut down! (For very ancient datings, radioactive decay may be used.)

Dating the ship's wood poses a different problem. Some sequence of wide and narrow rings will likely be visible, creating a "fingerprint pattern" common to different trees over a wide area during that time period, says Dawkins. And since dendrochronologists compile library catalogues of these labeled signature patterns, once the ship's wood is matched to a pattern in a library, its age will fall right out of the tree.

Q. Had my parents waited five minutes or maybe half an hour or longer before having sex that led to my conception, how might I differ from the person I am today? –M. Hyde

 A. There may have been no fertilization at all. Or if so, likely it would have been the same egg by a different sperm, meaning "you" could have wound up of a different sex, of different physical appearance, personality traits, susceptibility to diseases, and on and on, says Southern Illinois University School of Medicine physiologist Andrzej Bartke.

Still, the two you's would probably resemble each other more closely than just siblings, because half of the genes would have been contributed by the same egg. A longer delay in fertilization and implantation, by 1-2 days relative to ovulation, would increase the chance of miscarriage, adds Yale University perinatal researcher Errol R. Norwitz. So, dear reader, count your blessings.

Overall, which sperm wins the race is largely a matter of chance. Aldous Huxley described this best...

"A million million spermatozoa,

All of them alive,

Out of this cataclysm but one poor Noah

Dare hope to survive,

And among that billion minus one

Might have chanced to be

Shakespeare, another Newton, a new Donne–

But that One was Me." (c. 1920)

Q. Can dreams foretell the future? –K. Lyle

A. In one sense, they obviously can: If you dream of arguing with your boss, this could reflect tensions in your relationship, foreshadowing even worse problems ahead. Mathematician John Allen Paulos told of dreaming as a kid that he hit a grand-slam home run, then two days later he hit an actual bases-loaded triple. Coincidence? Paulos figured it was. For of the thousands of wish-fulfillment dreams over a lifetime, even if they're 1-in-10,000 long-shots, chance alone will assure a few come true.

More remarkable was a sleep laboratory dream recounted by Dr. Peretz Lavie in The Enchanted World of Sleep. On most nights, sleeper R. reported long, detailed, logical-sounding dreams, but one night he awoke to report nothing except the word "carbide," which he said "stuck in his mind." Three days later the worst industrial accident in history occurred in Bhopal, India, killing 4,000 and injuring 20,000 more– at Union Carbide Company! Hearing the news, Lavie was stunned. Had it happened to anyone else, he says, he wouldn't have believed it.

"I have no convincing explanation, and so it joins the other reports of unusual dreams in the scientific literature, dreams which provide evidence of the multifaceted character of the abundant world created in our brains each night."

Send Strange questions to brothers Bill and Rich at strangetrue@compuserve.com.