Word: planet
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Dates: during 1980-1989
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...depleted over Antarctica. The scale of the mission reflected an intensifying push to understand the detailed dynamics of potentially disastrous changes in the climate. The danger of ozone depletion is only part of the problem; scientists are also concerned about the "greenhouse effect," a long-term warming of the planet caused by chemical changes in the atmosphere...
...Rowland and Molina announced their conclusion: CFCs were weakening the ozone layer enough to cause a marked increase in skin cancers, perhaps enough to perturb the planet's climate by rejuggling the stratosphere's temperature profile. In 1978 the U.S. banned their use in spray cans. "People assumed the problem had been solved," recalls Rowland. But the Europeans continued to use CFCs in aerosol cans; other uses of CFCs began to increase worldwide. Says Rowland: "All along, critics complained that ozone depletion was not based on real atmospheric measurements -- until, that is, the ozone hole appeared...
...unusual global warming has indeed begun. Unlike ozone depletion, the greenhouse effect is a natural phenomenon with positive consequences. Without it, points out Climate Modeler Jeff Kiehl, of the National Center for Atmospheric Research, "the earth would be uninhabitable. It is what keeps us from being an ice-frozen planet like Mars." Indeed, if gases like CO2 did not trap the sun's energy, the earth's mean temperature would be 0 degrees F, rather than the current 59 degrees...
...made it clear that catching up was only the beginning. He has now directed his considerable intellect, political capital and diplomatic charm to another high-risk international mission. If all goes according to plan, the Phobos probes will take off next summer for Mars. When they reach the Red Planet some 200 days and 118 million miles later, they will orbit for a time, taking data on solar physics. The first Phobos will match orbits with the moon for which it is named, a chunk of rock about 14 miles across believed by many astronomers to be an asteroid captured...
Sagdeyev has even higher expectations for the Mars Sample Return mission, now being planned for the late 1990s. The idea is for the spacecraft to make a soft landing on the planet and send a rover to gather soil samples on a yearlong trek over the surface. Then about 2 lbs. of material would be returned to earth for detailed analysis. In Sagdeyev's plan, the U.S. would supply the rover, plus advanced electronics to guide it from an orbiting mother ship...