Word: sunlight
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
Even more to their astonishment, researchers discovered that biology played an important role in the rock-dissolving process. By poring over slices of limestone under microscopes, scientists found the fossil remains of primitive bacteria that had thrived in the once hostile environment. Using sulfur instead of sunlight as their source of energy, these organisms actually bolstered the acid's power to etch rock. Descendants of these strange microbes have recently been found and are being studied at Lechuguilla Cave, not far from Carlsbad...
...looking at fossil specimens and studying current species, researchers have concluded that most cave dwellers started out at the entrance of the cave. As they and their descendants traveled deeper inside and away from sunlight, they began to lose their eyes and develop other sensory organs to compensate. But is this loss an active process or just a question of disuse? "That's been a raging debate ever since Darwin's time," Poulson says. "What we've found is that it's disuse. There is no natural selection to screen out any bad mutations that affect the eyes. So eventually...
...orbital path of Comet Swift-Tuttle. If the comet ever happened to be there, the 10-km-wide (6-mile) chunk of ice and rock could slam into the planet, carving an enormous crater, generating tidal waves and throwing up a worldwide pall of dust that could block sunlight for months. Plants would be largely wiped out, and so would many species that ultimately depend on plants for food -- including, perhaps, the human race. Just such a disaster, many scientists believe, killed off the dinosaurs 65 million years ago. A smaller strike in the Atlantic 35 million years ago, described...
...possible? An analysis by UCLA scientists points out that while the poles are bathed in scorching sunlight, the light hits at such a shallow angle that the floors of some craters are permanently in shadow. With no atmosphere to move heat around, the temperature in these spots is far below zero. Any ice that condensed as frost in the craters billions of years ago when water boiled on the planet's surface as it formed would still be around today -- and evidently...
Probes and people would sally forth into the deeper universe, propelled by thin sails filled by the feeble but inexorable pressure of sunlight or traveling on ion drives that get their boost by shooting high-energy electrified particles out of the rear of the vehicle. Other possible vehicles for space travel may be propelled by a series of tiny thermonuclear explosions using pellets of fuel mined on the moon, or by mass drivers employing electromagnetic fields to expel bucketloads of dirt from the back...