What Lives On Mars?

Press, Volume CV, Issue 30965, 22 January 1966, Page 5

What Lives On Mars?

(By

ROBERT COWEN

in (he

“Christian Science Monitor")

gVERY bit of data we have about Mars,, including the Mariner photographs, shows it offers a very harsh environment for organic life. Yet many scientists continue to think that some form of life may eventually be found there.

For example. Dr. Wolf Vishniac, who heads the department of biology at the University of Rochester, says: “There are some obvious, although restricted, possibilities into which life as we know it might fit on Mars.” Stanley Millar, a biochemist at the University of California at San Diego, says: “I don’t think the statement that conditions on Mars are too harsh for life is a valid conclusion.” Comments made to the press by these. men during the annual meeting of the American Association for the Advancement of Science typify the outlook of many other scientists studying Mars today. Dr. Vishniac pointed out that, on Mars, “there is everything we need for life.” There is sunlight, at least a thin atmosphere, and some although not much water. There seems to be little free oxygen. But then, Dr. Vishniac said, oxygen isn’t essential for organic life even on earth.

He explained that photosynthesis, in which oxygen is produced, and respirations of animals, in which it is consumed, are characteristic of the community of organisms that inhabit the earth. But it is possible to have photosynthesis without producing oxygen or to have respiration without consuming it. Other elements can take the place of oxygen. In some bacteria sulphur does the job. On Mars, iron might do it.

Dr. Vishniac noted that there is some reason to think there may be iron oxide in quantity on the Martian surface. In that case, the Martian “oceans” in which life could exist might be “oceans” of iron oxide. There would 'be some water associated with the mineral, too, at least enough for hardy organisms. If it turns out there really is not much iron oxide on Mars, Dr. Vishniac said, “I'd have to come up with some new ideas.” But, he added, that this kind of speculation illustrates what he means when he says there are “restricted possibilities" for life on Mars, to judge from what is known today. Also, he said, even if no life is ever found on Mars, this would greatly interest biologists. It would help them learn more about how organic life does evolve by showing what had happened to suppress evolution on a planet that seemed somewhat favourable for life.

Dr. Stanley Miller put the question in a different perspective. He pointed out that even earthy organisms can live and grow in some very rugged environments. He said that the lowest temperature at which the growth (not just survival) of micro-organisms has been confirmed on earth is 25 degrees below zero centigrade. This is near the point at which a concentrated solution of sodium chloride (table salt) freezes. It shows that microbes can use such “antifreeze” to maintain their activity. One of the biggest problems organisms would face on Mars is a shortage of water. The thin Martian air is very dry. Yet, Dr. Miller observed, at a temperature of around minus 80 degrees centigrade, that air becomes saturated.

The relative humidity is ■then 100 per cent. If organisms could remain active at as low a temperature as this, a temperature to be expected

on Mars, they could pick up moisture directly from the atmosphere. Dr. Miller noted that a calcium chloride solution will go to minus 55 degrees centigrade without freezing. Lithium chloHde will go to minus 75 degrees centigrade. This begs two questions. Can organisms thrive in such exotic salt solutions? If they can live in them, can they do it at very low temperatures? Micro-organisms have been grown in such salt solutions at 25 degrees above zero centigrade. Dr. Miller said. But it has not yet been shown that they will grow in them at minus 80 degrees. However, this is something that can be and will be studied in the laboratory. Meanwhile. Dr. Miller said, it has been shown that “there is no reason why organisms can’t grow in environments foreign to our everyday sitution.” Also, there is no fundamental reason known today why organisms couldn’t live and grow under Martian conditions.

The question of what early conditions may have been on Mars is something else again. Dr. Miller said that not enough is known about how life arose on earth to say whether or not similar conditions would have had to prevail on Mars for organic life to get started there. But, he added, if life once did arise on Mars, it could have evolved into forms that can cope with present Martian conditions.