Sky gem more a place than object

Press, 24 August 1988, Page 21

Sky gem more a place than object

MICHAEL SNOWDEN, the author of the article at right, is an astronomer who lives in Tahiti, and has been gazing at Mars for many years. He is a stellar astronomer specialising in photometry and spectroscopy, but our planetary neighbour has always held a special fascination for him. He has been a staff member at the Kitt Peak National Observatory, in the United States, and the Mount John Observatory above Lake Tekapo.

Different perceptions of Mars in the last 100 years: at left is a drawing made by a French astronomer in 1892, when the planet was nearer to Earth than usual. Features drawn some years before Lowell saw “canals” could be interpreted as some sort of waterway. At right is Mars photographed through a telescope from South Africa in 1939. Below is a Martian feature — photographed from the American spacecraft Mariner 9 from 2000 km above Mars — which has nothing to do with earlier “sightings” of canals. It is 480 km-long chasm with branching canyons that could be dry riverbeds.

In September and October, many New Zealanders will be surprised to see a dazzling object rising in the sky, shortly after sunset in the northeast. While the appearance of the planet Mars will be new to many, it is by no means new to astronomers. It appears in the opposite side of the sky from the sun, and makes a relatively close approach to us at the same time every two years. These Martian oppositions occur frequently enough, but few are quite so impressive as this approaching one. At its closest on September 22, Mars will be a mere 59 million kilometres from the Earth, and will offer Earth-bound telescopic viewers and researchers an exceptional opportunity to examine this near neighbour. The Soviet Union is certainly aware of this opposition, having just launched two major unmanned spacecraft to explore the planets and Phobos, one of Mars’ small moons. Fundamental questions of astronomy during this century have mostly been related to the origins and evolution of the stars and galaxies. While fiction writers have placed some of their most imaginative stories in a Martian setting, scientists have been seriously examining its environment for traces of life. For me there is a personal fascination for Mars which goes back to 1954. I was 14 years old then, growing up in the farm country of, Tennessee. There were not many young friends around then, and my interests were limited to things the local environment offered: bugs, snakes, and stars.

Stars won out, and I eventually became an astronomer, but it was really Mars that beckoned me in those early years. It burned as a steady beacon in the morning sky with its strange bronze-copper light. At that time, there were still sone intriguing unanswered questtions about the planet. Were the enigmatic “canals” depicted early in the century by Percival Lowell authentic?

By 1954, no-one still seriously believed that Lowell’s observations showed a civilisation, but the possibility of Martian vegetation seemed real. That was well before the Mariner 9 and Viking spacecraft of the 19705, and I became enthralled by the unanswered questions of canals, vegetation, and life. These space probes ended the controversy, once and for all.

No traces of canals were found in their high-resolution photographs. The pictures did reveal some fascinating dry riverbeds, not visible from the Earth, along with a dramatic canyon and towering volcanoes. In terms of sheer size, these natural features are far more impressive than any of Lowell’s imagined canals.

The scale of expanding scientific knowledge, and the subsequent impact of mankind during the last half of this century, is without precedent.

The pace of this progress is not likely to slow down after the year 2000. Fortunate indeed is the person who follows ,the thread of this great human adventure rather than becoming bored by the routines of daily life. People are also aften directed by astrology and other

banal pseudo-sciences. Unfortunately, Mars has been a focus for these activities as well. Even now, Mars does not hold centre stage as a great unsolved mystery of nature, but it still intrigues me. For one thing, I am impressed by how its significance to us has changed with our improved knowledge of it. In a sense it is no longer a purely astronomical object. It has been transformed from a tantalising astronomical point in the sky, which I watched as a youngster, to a place. If it is perceived as a place rather than an object, then people will want to go there, and Thomas Paine, the NASA administrator during Project Apollo, has predicted that there will be 100,000 people living on Mars by 2085. Although there remain some interesting research problems for the curious scientist, the pursuit of Mars is rapidly moving from science to engineering. How can we get there? How can we explore it as a part of the inquisitive and restless human spirit? It is a wonderful example of how our exploration of science and nature changes our perception and, still more deeply, our human identity. Perhaps there is no life on Mars, but soon there will be. Still, it will continue as a gem in the sky for me. The other night I was up at 1 a.m. and went out for a look to find my old friend rising rapidly over Christchurch. It was bright, bronze, and enchanting. Once again, I will turn a telescope towards it, but at this opposition, I will know what I am seeing.