The water controversy of the Red Planet

When focusing on the planets of the Solar System, Mars has fascinated many, especially children, not just for its beauty, but also for the many myths related to this tiny Martian planet.

The stories about the possibility of alien life or Martians being on Mars is not just made up to entertain children. It has stirred up some serious talks over the past few years, leading to exploration to ascertain if any form of life is evident on this planet or not. So, where did all these questions lead to?

It led many a scientist to check out whether Mars has at least the basic elements needed to support life on it. And, one key issue was to find the presence of water on Mars.

Aravinda Dassanayake

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What people initially thought

The controversy about water being present on Mars has an interesting beginning. Even before space explorations started, there was a belief that intelligent beings may be present on Mars.

After images of Mars were obtained through space probes, the lines which were visible crisscrossing the planet were believed to be irrigation constructions by these so-called intelligent beings. Apart from this, there was evidence of Mars changing its colour seasonally.

This made scientists think that it was the result of seasonal changes in the vegetation on Mars. For instance, there would be one colour during the period where vegetation was in bloom and a different colour when it was not, and so on. All of this may sound silly to you right now, but, the fact is that these views also existed for some time.

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The journey towards reality

Everything started to become clear only when the space probe, Voyager-4 transmitted 22 close-up photos of Mars in 1965.

These revealed that all the stories floating around, until then, were hoaxes and that there is no running water on Mars. Thereafter, when the Viking 1 and 2 landed on Mars, it was further clarified that Mars has a different story to tell us.

Martian air contains only about 1/1,000 as much water as our air, but even this small amount can condense (become solid), forming clouds that ride high in the atmosphere or swirl around the slopes of towering volcanoes. Patches of early morning fog can also form in valleys.

At the Viking Lander 2 site on Mars, scientists had noticed a thin layer of water frost covering the ground each winter.

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Latest investigations

The Mars Express project is now under way, and it has started to change the way we think about Mars since its launch on June 2, 2003.

"We are re-writing the history of Mars," says Gerhard Neukum, of the Freie Universitaet Berlin, Germany, and the Principal Investigator on Mars Express' High Resolution Stereo Camera (HRSC).

"The big picture of a warm wet Mars is not completely correct. Any warm wet period lasted only a few hundred million years. By four thousand million years ago, it was over," he explains in his reports on Mars.

Advance instruments on Mars Express generate all these new results. The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) has shown that many of the upper layers of Mars contain water ice. This has revealed reservoirs of ice and scientists are investigating when it existed as liquid.

The OMEGA detected clay-like minerals that form during long-term exposure to water, but only in the oldest regions of Mars. This suggested that water flowed during the first few hundred million years of the planet's history only.

The images from the High Resolution Stereo Camera (HRSC) point towards the conclusion that extremely old Martian regions have been eroded by flowing water. The pictures also show a huge valley, Kasei Valles, carved by a gigantic glacier that existed for a thousand million years during the time when the temperature of Mars had dropped too low for liquid water to flow across the surface.

Mars Express data is still streaming down from HRSC, MARSIS, Omega and they are probing all aspects of the Martian environment studying atmospheric gases, searching for eventual biological processes, and trying to explain the unsolved.