Word: polarizer
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Fired to an altitude of 492 nautical miles, the satellite is expected to operate for a year in a near-polar orbit that runs almost parallel to the earth's axis of rotation. Sweeping down from high above the Arctic Circle to Antarctica, it will then head back north every 103 minutes. This orbit has an important advantage: it will bring the spacecraft back over the same spot on earth every 18 days at almost exactly the same time of day. Thus, ERTS's photographs, each covering a 100-by-100-mile square, will be taken at each...
...planet last November. By patiently matching and assembling these photographs, scientists at Caltech's Jet Propulsion Laboratory have put together a jigsaw-puzzle-like map of a strip of Mars extending 30° above and below the equator as well as an overall view of its south polar cap. Indeed, detailed photographs, showing features as small as 100 yards across, were among the highlights of the 15th annual session of the international Committee on Space Research, attended by more than 1,000 scientists from 35 countries...
...into the rhythm of the sermon, everyone had to reach out and possess each maxim as if it were a truth of infinite wisdom that had never been expressed before. An organic interchange of energy and enlightenment flamed up with every sentence, accelerating until all strength was spent. The polar opposite of a Harvard lecture...
...like a spinning gyroscope, Mars slowly wobbles as it travels around the sun. Though this motion, or precession, is barely perceptible, the Martian axis leans in the opposite direction every 25,000 years, or halfway through a complete precessional cycle. When that happens, the northern polar area is angled toward the sun at the planet's closest approach, while the southern polar area, tilted away, freezes and traps the moisture. What interests Smith, however, is the orientation of the poles in between those extremes. Then, both polar regions receive equal heating from the sun. The warmer outer portions...
...glacier-like quantities of frozen water have accumulated in either polar cap, says Smith, enough water might be released to keep the monsoons going for centuries, and possibly millenniums, until the slow precession of the planet's axis causes one pole to begin cooling enough to draw water back out of the atmosphere and into the Martian deep freeze for another 25,000 years. Even if the monsoon theory is correct, however, many centuries will pass before visitors to Mars will have to shoot Martian rapids or brave unearthly downpours. Mars has just passed the point in its precession...