Frozen in Time
August 29, 1998 | Volume 154 | Number 9
Cover: Hidden in horizontal stripes on this Namibian cliff are clues to one of the biggest climatic crises in Earth's history. More than 700 million years ago, the planet may have become completely entombed in ice, according to a new hypothesis.The cliff displays a thick stack of carbonate rocks that record conditions just after that ice age. (A.J. Kaufman)
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News of the Week:
Male Good Looks Take Feminine Turn
Men whose faces have a slightly rounded, feminine shape may look more appealing to women, for reasons grounded in humanitys evolutionary past.
Robotic weather-vane-to-be crosses sea
A 13-kilogram miniature plane became the first robotic aircraft to fly across the Atlantic Ocean, raising hopes for better collection of vital oceanic weather data.
Pregnant women who smoke transmit a potent cancer-causing substance to their babies before birth.
A sound way to take the sea's temperature?
Loud sounds emitted underwater can measure the temperature of the Pacific Ocean.
Magnesium: Another metal to bone up on
Like calcium, magnesium may be a pivotal mineral for preserving bones and heading off osteoporosis.
Female cardinal songs, which sound very similar to the male songs, have more overtones and are readily distinguished by the birds.
Hormone links malnutrition and immunity
The hormone leptin, known for its role in appetite, influences how immune cells act.
Any Mars life would be hard to find
Geophysical energy on Mars may have powered the evolution of a modest amount of microorganisms, perhaps too few for researchers to expect to find.
Drugfree dose of help for hyperactivity
A new parent training program may offer an effective treatment for children with attention-deficit hyperactivity disorder, without the need for medication.
Up close and cultural
Turkish women report fears of interpersonal closeness and abandonment not characteristic of Westerners but that may be useful in forming intimate relationships in that culture.
BiomedicineAlzheimer's link to eye disease seen
A mutant variety of the gene that codes for apolipoprotein puts people at lower risk of developing Alzheimers disease but at higher peril of getting macular degeneration.
Reducing the risk of ovarian cancer
Women with a mutation in a BRCA gene, who face an increased risk of ovarian cancer, may be able to reduce that risk by taking birth-control pills.
Earth may have repeatedly lurched back and forth from being totally ice-covered to basking in a greenhouse climate.
The king of all ice ages may have spurred animal evolution
Why Guys Get Fancy
Female preferences may explain why male genitalia seem to evolve more rapidly than other body parts.
The diversity of private parts mystifies biologists
Twists Through Space
Interactive software helps sculptors visualize and refine their creations
A collaboration between a sculptor and a computer scientist produces novel works of art.
Letters: A Selection from Letters to the Editor