Springtime for Planet Neptune
Neptune, the eighth planet from the sun, is known for its strange and violent weather, with winds gusting to 900 mph. But until now, no one knew that this giant ball of gas so far from the warmth of the sun might have a springtime.
Hubble Space Telescope observations of the planet made over a six-year period show the planet is brightening considerably in the southern hemisphere -- a harbinger of seasonal change, scientists say.
"Neptune's cloud bands have been getting wider and brighter," apparently in response to seasonal variations in sunlight, said Lawrence A. Sromovsky, of the University of Wisconsin-Madison, who has made extensive studies of Neptune's atmosphere.
It is now late spring in the Neptunian southern hemisphere, he said, where a visitor would feel "relatively modest temperatures" close to the boiling point of liquid nitrogen, or 321 degrees below zero Fahrenheit.
"No need for a sun block," he added. Neptune is the coldest of the major planets, and the sun's intensity there is 900 times weaker than at Earth.
The amount of solar energy absorbed by a planet's hemisphere at a given time is what determines the season. Neptune, like Earth, is tilted at an angle relative to the sun. As the planet spins, the slant exposes each hemisphere to varying amounts of solar radiation as it orbits the sun. Neptune takes 165 years to circle the sun, compared with Earth's 365 days. The 40-year winters there "could seem a bit tedious," said Sromovsky, who worked on the project with researchers from NASA's Jet Propulsion Laboratory.
The most remarkable aspect of the finding, described in the current issue of the journal Icarus, is that a planet so far from the sun shows any sign of seasonal change at all, he said.
-- Kathy Sawyer
Knowing Beans About Genes
A decade of news, education and entertainment on the hot topic of genetics has left the U.S. population no more savvy about the subject than it was in 1990, according to a nationwide survey.
The brief telephone survey, conducted by the University of Michigan's Institute for Social Research, questioned 1,006 respondents in 1990 and 1,824 respondents when the survey was repeated in virtually identical form in 2000. Part of the survey asked about attitudes toward genetic testing and related topics, with no right or wrong answers. But the survey also included five true-false questions.
Overall, a smaller proportion of those five questions were answered correctly in 2000 than in 1990. For example, 58 percent of respondents answered at least three questions correctly in 1990, while only 24 percent did so in 2000.
Here's a crib sheet, with the five questions, paraphrased, and the correct answers:
1. Genetic tests can find out if an adult has an above-average chance of developing certain cancers. (True, although the tests offer probabilities and cannot predict an individual's medical fate.)
2. Genetic tests can find out if an adult has an above-average chance of developing depression. (False; no gene has been identified as a major risk factor for depression)
3. Genetic tests can predict whether a person will have a heart attack. (False; heart disease, like depression, is the result of minor susceptibilities conferred by many genes, plus environmental factors such as diet or exercise.)
4. Genetic tests can be used during pregnancy to find out whether the baby will develop sickle cell disease or cystic fibrosis. (True; each of these diseases is caused by a defect in a single gene.)
5. Gene therapy is currently being used to correct many genetic defects (False; only one disease -- a childhood immune deficiency -- has been cured by gene therapy, and those treatments are on hold in this country because of recent evidence that they can cause cancer.)
-- Rick Weiss
Extinction of Languages
Languages may be disappearing faster than birds and mammals, according to a new analysis.
William J. Sutherland of the University of East Anglia in Britain evaluated the danger of extinction that all 6,809 "living" languages face using the same criteria used to determine the risk that species face of being wiped off the planet.
Sutherland determined whether the languages were "critically endangered," "endangered" or "vulnerable" based on the estimated number of speakers that still exist and the estimated rate of decline.
"Languages are more threatened than birds or mammals," he concluded in the May 15 issue of Nature.
There are 357 languages that have 50 or fewer speakers, he said.
Sutherland also found that places with a large diversity of languages also tended to have a wide diversity of birds and mammals. "And all three show similar relationships to area, latitude, area of forest and, for languages and birds, maximum altitude," he wrote.
He was surprised, however, to find that there was no relationship between the time a country was settled and the diversity of language.
-- Rob Stein
