Page 309 - NS-2 Textbook

304 NAUTICAL SCIENCES

A view of the planet Jupiter from Pioneer 10 shows the clOUd tops
and the famous Red Spot. The spot is 25,000 miles wide, about three
times the diameter of Earth, and may be a permanent storm in the
upper atmosphere.

Jupiter can easily retain all kinds of gases in its at-
Artist's rendering of the 2004-5 Mars rovers Spirit and Opportunity mosphere, especially hydrogen and helium. The whirling
showing their abrader tool extended. Both returned thousands of planet rotates so swiftly that a day is only ten hours long.
spectacular images of the Martian surface and much data about its The force of Jupiter's gravity is such that a ISO-pound
composition. )PLlNASA
man would weigh 350 pounds at the equator and 425
pounds at either pole.
Travel to Jupiter by astronauts is beyond the most
solve the many questions about water on Mars and the advanced space technology today. TIle twenty-one-month
possibility of former or current life on the planet. trip itself would be beyond the capability of present life-
support systems. Also, communications would have a
forty-five-minute lag because of the distance to it. Tem-
JUPITER
peratures above the planet's cloud layer are about -200
Jupiter is the fifth planet from the Still. Larger than all the degrees F, and much higher temperatures, possibly in the
other planets put together, its diameter is more than ten thousands of degrees, exist closer in. The chief peril,
times that of Earth. It orbits about 484 million miles from however, comes from Jupiter's radiation belts. Lethal
the Sun and never comes closer to Earth than 367 million doses of radiation, a thousand times more than a hrnnan
miles. Despite its great distance, it usually outshines being could stand, were sustained by Pioneer 10 for sev-
everything in the night sky except the Moon and Venus. eral haUl'S prior to its point of closest approach. It seems
Named after the king of the Roman gods, Jupiter re- possible that Jupiter is sUl'l'Olmded by radiation belts
mained an almost complete mystery until NASA's Pio- sinillar to Earth's Van Allen belts.
neer 10 passed within 82,000 miles of its cloud tops in De- The atmosphere of Jupiter is made up mostly of hy-
cember 1973. Pioneer 11 moved to within 27,000 miles a drogen and helium. There also are small but extremely
year later to find out more. important amOlmts of methane, ammonia, and water.
Two U.s. Voyager spacecraft with more advanced in- Wide, circling bands of white, yellow, brown, and gray
struments flew by Jupiter and several of its moons in make up much of Jupiter's face. Inside these belts of
March and July 1979. Many superb color pictUl'es of the clouds there is TIllieh turbulence, and jet streams race
planet and its foUl' major moons, la, EUl'opa, Callisto, and through the area. Farther in, after an area of relatively
Ganymede, were transmitted back to Earth. Several spec- clear ahnosphere, there is a darker cloud deck. It con-
tacular new discoveries were made, including sulfur and sists of dark yella,,,,, orange, and brm.vn clouds, com-
sulftu' dioxide vulcanism on 10 and V\'ater ice on Callisto posed mainly of icy particles of anunonium hydl'Osul-
and Ganymede. fide. The nmermost layer of clouds is a massive, thick