Lethbridge Herald, The (Newspaper) - April 29, 1974, Lethbridge, Alberta
Monday, Apm n, THE LETHMiDOK HERALD t Exploration shrinks our solar system By DAVID F. SALISBURY Christian Science Monitor fiery ball that dominates Mercury's sky looks six times bigger than our own familiar sun. But seen from beyond the asteroid belt, from the massive planet Jupiter, it shrinks to a small, bright disk. This is one measure of the expansion of humanity's world; And that part of the solar uystem now surveyed by instruments may one day be claimed by manned exploration. Presently, Seven planetary probes are strung out through that territory between Mercury and Jupiter. Four are Soviet craft headed for Mars. America's Mariner 10 is going to Mercury by way of Venus; Pioneer 10, having already passed Jupiter, now is heading out of the solar system entirely; and its sister probe, Pioneer 11, now traveling toward Jupiter, may be routed to take in Saturn too. When and if Pioneer 11 reaches Saturn, modern man will have sent scientific instruments to every planet that the ancients saw, revered, and named after their gods. James C. Fletcher, head of the U.S. National Aeronautics and Space Administration (NASA) calls these twelvefold increase in the range of firsthand study of the solar "peak of Man's exploration of the planets." Before this time, we had reached out only to our nearest planetary and Venus. Although they differ markedly with Earth in some respects, they are still "terrestrial" planets, similar to Earth in size and composition. That's why scientists are especially excited about Mercury and Jupiter which, as solar- system planets go, represent the extremes: Mercury is the smallest planet, only a little bigger than Earth's .moon, and with little atmosphere. Nevertheless, it is by far the heaviest planet for its size. In contrast, Jupiter is one of the lightest, yet 600 Earths would fit beneath its pastel-banded clouds. The two planets also differ in suitability for organic life. "If a scientist were looking for organic life similar to that on Earth, one of the first places he would look is says Dr. Carl Sagan, director of Cornell's Laboratory of Planetary Studies. On the other hand, no one expects to find life of Mercury, just miles from the sun. Planetary scientists do, however, hope to find there a record of the days when the planets formed. Its seared and fissured surface should provide clues, just as do the craters on the Moon and Mars. After geologists began studying the Apollo photographs of the Moon, they found that the millions of craters covering its surface were an important key in determining the age of lunar features. Roughly, the more densely a lunar "sea" or rill is pocked with craters, the oltier it is taken to be. Also, lunar scientists have found that the biggest craters are the oldest. Apparently, 4-6 billion years ago, meteorites rained on the Moon's surface. By four billion years ago this infall had almost ceased. Recently, planetary geologists have realized that Mars has a similar history. They had expected that Mars would have received ten times as many meteorite hits as the Moon. But at the last meeting of Mars experts at California Institute of Technology Laurence Soderblom of the U.S. Geological, Survey announced the cratering history of Mars and the Moon were strikingly similar. As a result, many of these scientists now feel they may be seeing the tail-end of the planet-forming process. According to current thinking, the solar system evolved from a cloud of gas and dust. As the sun formed, its gravitational attraction forced the remaining material into a series'of rings similar to those now circling Saturn. These consolidated into planets which gradually swept up most of the remaining material. As principal investigator for Mariner 10's television cameras, Cal Tech's Bruce Murray will have the first detailed look at Mercury's surface. If the planet's history is similar to Mars and the Moon, it'will indicate that this one planet-forming process took place throughout the inner solar system. But Mercury may only reflect the sun's early history. Because the planet is so dense, early solar explosions may have vaporized its outer crust, leaving only the inner core. If either of these theories is proved true at this time it will be because of the clarity astronomers expect from Mariner 10 pictures. The spacecraft's cameral should resolve features as small as 300 feet on a side. At last, astronomers should see what kind of surface is returning radar echoes which, so far, just give a general indication that part of the planet is rough and the rest smooth. They may even find out if the whitish haze some observers have claimed to see really exists, and whether or not it is due to dust storms. On its way to Mercury, Mariner 10 will pass by Venus. Its pictures will be the first of the lemon- yellow clouds that perpetually shroud the planet. It will approach Venus from the shadow (night) side. Just before the point of closest approach, it will emerge into sunlight. Although Earth and Venus are similar in size, weight, and distance from the sun, Soviet probes have already confirmed that its surface temperature is 900 degrees (both day and They have reported, too, that its atmospheric pressure is 100 times that of Earth. Looking up from the surface you would think you were standing in a bowl, because of the way the thick atmosphere bends light rays. Venus' high temperature and pressure are due to huge quantities of carbon times that in Earth's atmosphere: Scientists have yet to explain where this carbon dioxide came from. Mariner's cameras won't resolve that problem. But they will be looking for evidence of Venus' weather. Because Venus only turns once every 243 days, its atmosphere behaves differently from our own. Meteorologists have forecast what Venus weather patterns should be, adapting their knowledge of Earth's atmosphere to Venusian conditions. But they can't account fully for what even now is There are very high-level clouds that race around Venus' equator. cloud tops pump up and down on a regular four-day cycle. By looking closely at the cloud structure, Mariner 10 may provide data to prove or disprove some of the assumptions that atmospheric scientists make about weather on Earth. While Mariner 10 completes its journey, investigators will be studying the results of Pioneer 10's swing around Jupiter. The information from that should help them decide whether to route Pioneer 11 past Saturn. Jupiter is thought to be largely a ball of liquid and gas. It may not have a surface in the traditional sense. Instead, its clouds may thicken until they become liquid under increasing pressure. Also the planet is a little like a star in that it gives off more heat, in fact. As Pioneer 10 skimmed miles above Jupiter's clouds, it photographed pastel stripes and the mysterious red spot that dominates Jupiter's surface. The color of the darker, brownish bands is similar to that of an organic soup made in several laboratories by electric sparks flashing like lightning through the typical gases of Jupiter's atmosphere. This has led Dr. Sagan to describe _that atmosphere as a vast organic "laboratory, where organic materials may fall like manna from heaven into ammonia-water seas." Other laboratory experiments have shown that terrestrial microorganisms can survive environments as highly alkaline as that of Jupiter is thought to be. More skeptical scientists, such as Nobtl Prize winner Joshua Lederbere of Stanford University, point out that no terrestrial organism known could survive in the Jovian mix of ammonia and water. The primary purpose of Pioneers 10 and 11 is to investigate the magnetic field and radiation belts that surround Jupiter. In 1977, NASA plans to send two spacecraft with high-powered television cameras to Jupiter and Saturn. But first it was necessary to find out whether or not radiation would damage these probes if they came close enough to use Jupiter's gravity to send them on to Saturn. Pioner 10 has shown that these future craft should survive. Pioneer 11 now is committed to pass even closer to Jupiter than its predecessor. Neither the current Pioneers nor the future Mariners will look for life on Jupiter or other outer planets. If it exists on Jupiter, organic life must lie below the clouds where the planet's internal heat provides enough warmth for life processes to function. However, the primary purpose of America's Viking mission, scheduled for launch in 1975, is to search for Martian life. Each Viking lander will carry an entire chemical transistors, other electronic parts, and 37 miniaturized valves stuffed into one cubic foot of space. There will also be a stereo TV camera that will look for "slow-moving Martian as one investigator puts it. Landing sites for the Vikings already have been near the end of a spectacular Martian canyon, the other at the fringe of the north polar rap. The four Russian Mars probes are not equipped to search for life itself. But they could gather more information about the Martian surface. If their equipment works correctly, they could help answer a crucial question about the prospects for Martian life is water available in useable form? There is a growing consensus among Martian investigators that Mars has been an active planet. Channels, apparently cut by flowing water, have formed over long time spans. Vulcanism, the chief method by which a planet creates its atmosphere, also has been active. Thus Mars may once have had an earthlike atmosphere, perhaps even a series of such atmospheres bver at least the last billion years. However, Mars is not the most likely place in the solar system to look for life. One of the most exciting prospects for life now appears to be Titan, Saturn's largest moon. Recent infrared measurements indicate that it is much hotter than it "should" be. Dr. Sagan speculates that it may have atmospheric conditions similar to those on Earth. The earliest possibility for a close look at Titan probably will come if Pioneer 11 is routed to Saturn. In case, the spacecraft would arrive at the ringed planet in October, 1979, extending humanity's outreach ever farther across the solar system domain it will eventually consider part of the estate it calls home. What was before the universe? By DAVID F. SALISBURY Christian Science Monitor SAN FRANCISCO What happened before the universe began? Ever since the widespread acceptance of the "Big bang" theory of creation, scientists have been guessing about what came before the primeval explosion that set into motion the universe as we see it. Now they believe they have caught a glimpse of that immensely distant time. As scientists mentally and mathematically put the universe in reverse, they saw it shrinking, galaxies overlapping and merging into matter- energy soup. Temperatures rose to billions of degrees. More and more matter turned into energy. Approaching within fractions of a second to the very beginning of time, however, pressures, temperatures, and densities of the newborn universe increased faster and faster. They became inconceivable except as mathematically defined quantities. Cosmologists could not believe what their mathematics told them, and wondered what really happened. At the annual meeting of the American Association for the Advancement of Science, Dr. George Field, director of the Center for Astrophysics in Cambridge, reported modifications in these equations that suggest the universe may have "bounced" in the trillionth of a second before oar present universe was born. Although they involve admittedly "unrealistic assumptions" about the behavior of particles at very high pressure and densities, these changes represent the first (serious) mathematical attempt to see beyond the big bang. "This keeps open the possibility that the present expansion of the universe was preceded by says Dr. Field. In that case, the apparent beginning of the universe might not be the real beginning. The universe may be pulsing: repeatedly increasing in size until its gravity stops it: repeatedly collapsing into a hot, dense mass: repeatedly recreating itself. "Peter Jackson" Ask for them either way. TheyVe the same satisfying cigarette Warning- The Department of National Health and Welfare advises that danger to health increases with amount smoked.