Science Made Simple

If Chicken Little calls out, "The sky is falling!" maybe we had better listen carefully. While the sky itself is not falling, chunks of satellites, rockets and other junk are falling from space with increasing frequency.

In June, NASA will bring down the Compton Gamma-Ray Observatory in a "controlled" reentry. The satellite should fall harmlessly into the eastern Pacific Ocean. But there is a growing concern over space junk hitting land. In 1979, large pieces of Skylab landed in Western Australia. Most recently, on April 27, 2000, more than 300 kilograms (700 pounds) of space junk crashed to the ground in South Africa. The pieces were later identified as the remains of a Delta 2 rocket used to launch a global positioning satellite in 1996.

Much of the space junk that falls from orbit is vaporized by atmospheric friction. And because oceans cover so much of the planet, chances are that the remaining fragments will hit in water. But more and more often, some of those pieces will hit land. The U.S. Space Command in Colorado Springs is currently tracking about 9,000 objects in orbit. Most of those are space junk.

Scientists are studying what happens to large objects during reentry. By looking at the pieces that survive, they hope to create new rocket and satellite designs that will pose less of a hazard when they eventually return to Earth. (5/00)

Do you feel insecure or less sociable when your hair is a mess? Well, you are not alone. A bad hair day affects more than just your looks. Researchers at Yale University found that how you feel about your hair is very important to your self-esteem. People do not feel as smart or capable as usual and are more easily embarrassed when their hair is a mess.

It's understandable that appearance has an impact on how people, especially teens, feel about themselves. But in a surprising twist, messed-up hair or a bad hair cut often has a more negative affect on men than it does on women. (3/00)

Sweet, sour, bitter and salty. Those are the four major tastes commonly recognized in Western cultures. However, Asian cultures include a fifth distinct taste. It is glutamate, also known by its Japanese name "umami." Scientists have now identified the taste receptors on the tongue that are responsible for umami.

Umami is described as a brothy taste - the flavor that meat, seafood and aged cheese seem to have in common. Glutamate, often in the form of MSG, is commonly used in foods to enhance flavor.

In related news, scientists from Yale found that temperature affects taste. Warming the front of the tongue produces a sweet taste, while cooling produces sour or salty tastes. Cooling the back of the tongue produces bitter or sour tastes. Temperature somehow affects the taste receptors, which send signals that the brain interprets as tastes. Although the effect is subtle, you can test this yourself. Try holding an ice cube to the tip of your tongue and see if it produces a salty taste. (2/00)

The common cold may not be the worst disease around, but it certainly is annoying. Finally, there may be a cure. Or at least major relief. It's a drug is called Pleconaril (pronounced plah-CONN-ah-rill), made by ViroPharma, Inc. It seems to shorten a bad cold by 3 to 4 days, while lessening cold symptoms. In addition to curing colds, Pleconaril also works against some other, much nastier viral diseases, such as flu, polio, and viral meningitis. Two large-scale tests will be completed by spring. If Pleconaril is as safe and works as well as expected, the company hopes to begin selling it late this year or in early 2001.

In the past, most medicines have been discovered by testing large numbers of different chemicals to see which could be useful. Now, medical science has taken a giant leap forward. Pleconaril was not discovered; it was designed! Scientists mapped the three-dimensional surface structure of the virus. Then they designed a drug which fits into a groove on the surface. This prevents the virus from infecting the body's cells. These same design techniques can now be used to target many other viruses, and give doctors new weapons in the fight against viral diseases. (1/00)

Hate the idea of cutting up a frog in biology class? You are not alone. More and more schools are using technology to replace hands-on dissections. Computer software is available that allows students to perform virtual dissections of frogs, pigs, cats, worms and other animals.

These programs have received mixed reviews from science teachers. Some approve, while others believe there is no good virtual substitute for the actual hands-on experience. (1/00)