Science Digest

In One Ear

If you need to bum a cigarette in a noisy Italian nightclub, make sure to ask someone in his or her right ear, says a study published last week in the German journal Naturwissenschaften ("The Science of Nature").

Studies dating back about 50 years have shown that humans prefer to listen with their right ears. This is a result of hemispheric asymmetry in the brain -- the left hemisphere, which is better at processing verbal information, is cross-wired to the right ear.

But those studies were performed in laboratories. Daniele Marzoli and Luca Tommasi of University of Chieti in Italy headed out to the discotheque to find out whether right-ear preference held up in natural social situations.

In one experiment, researchers observed 286 clubbers while they were trying to talk over booming music. Seventy-two percent of the listeners leaned in with their right side (this may be due to a greater right-ear sensitivity of right-handers, as reported in other studies).

In another experiment, a female researcher asked 176 clubbers -- 88 female, 88 male -- for a cigarette, intentionally speaking into the person's left or right ear. Predictably, men offered her more cigarettes than women. But the researcher received about twice the number of cigarettes when she spoke into the clubbers' right ears rather than their left. This is consistent with the idea that the right hemisphere of the brain specializes in negative emotions while the left deals with positive emotions.

-- Rachel Saslow

A Clue in the Clouds

Something came hurtling from outer space and flattened thousands of square miles of Siberian forest one day in 1908. The Tunguska event, named after a river in the impact area, has been a mystery. Was it a rocky object? A comet? Did any of it reach the ground, or did it explode when it hit the lower atmosphere?

Cornell scientists are siding with the comet hypothesis in a paper that incorporates "noctilucent" clouds that shine at night and the plume trail of a space shuttle.

The shuttle's engines generate large amounts of water vapor as it rockets into orbit. The plume trail, scientists have discovered, can spread out dramatically and travel thousands of miles, forming dramatic displays of noctilucent clouds at high latitudes. The clouds are so high -- some 50 miles up -- that they are in bright sunshine even when the ground is in darkness.

Mike Kelley, a Cornell professor who studies the upper atmosphere, stumbled upon references to noctilucent clouds being seen in England in the days after the Tunguska event. Kelley and his colleagues have published a paper in Geophysical Research Letters contending that the impact in Siberia had to be from a comet because only a comet, an icy object, would shed water vapor to form a noctilucent cloud.

"When a comet comes in, it's mostly ice. It's going to get rid of the ice very high up." Kelley said.

-- Joel Achenbach