Word: planetful
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
...planet has become an intricate convergence -- of acid rains and rain forests burning, of ideas and Reeboks and stock markets that ripple through time zones, of satellite signals and worldwide television, of advance-purchase airfares, fax machines, the miniaturization of the universe by computer, of T shirts and mutual destinies...
...times before, in fact, that the earth's surface would be as pockmarked as the moon's were it not for the cosmetic effects of erosion caused by the oceans and atmosphere. Half-mile asteroids are a dime a dozen in the solar system, and they run into the planet once every 100,000 years, on average. That means the next one could strike in a thousand lifetimes -- or before the end of next week...
Then there are the really big asteroids -- masses of rock and iron five or ten miles across that hit every 10 million to 100 million years. The half- milers are bad enough, but these giant ones pose a threat to the entire planet. It was such an asteroid (or an equivalent-size comet) that many scientists believe caused the extinction of dinosaurs some 65 million years ago. The primary evidence, discovered by the late physicist Luis Alvarez and his son Walter, a geologist, is a layer of the element iridium laid down in sedimentary rock at about the time...
...enormous chunk of space rock hit the planet, the Alvarezes theorized, it would have largely disintegrated, casting a pall of iridium-rich dust and other debris over the world that could have lasted for months. Deprived of sunlight by this all-natural version of "nuclear winter," plants -- and the animals that fed on them -- would have died in droves. And when the dust finally settled, the iridium it contained would have formed just such a layer as the Alvarezes found...
...rock into pieces that would hit the earth anyway. A better plan, proposed by concerned scientists in the early 1980s, would be to use explosives to deflect an asteroid rather than destroy it. Properly positioned, a bomb could nudge a threatening object enough to make it miss the planet. The catch, says Harris, is that there would not be much time to react to an approaching celestial body. "With an asteroid like this one," he says, "you'd probably get a day's warning at best." In short, the most sensible thing to do about earth-grazing asteroids...