An ancient ocean in Mars?

An interesting article was recently published on the journal Nature Geoscience in which the authors report evidence that suggests that Mars had an ocean of water, which covered about one third of its surface.

What is all this evidence about, and why do scientists conclude that there must have been an ocean in mars?

Well, Gaetano Di Achille and Brian Hynek of the University of Colorado in Boulder had been studying high resolution images of the martian surface, and were building a database of all the different valleys and river deltas in mars to propose a way on how they could have been created by water. As geologists explain: When a river flows it erodes rocks and soil; this process over millions of years creates valleys, which have a very significant impact on the landscape. This can be analyzed with current methods and the history of the land can be inferred from the analysis of the available data.
Di Achille and Hynek applied these methods to the Martian surface and they found that these deltas and valleys had very similar elevations and seemed to feed the same body of water; their observations also suggested that a coastline had been formed at these elevations.

A lot of questions still remain, since this new evidence still has a lot to demonstrate before it can really confirm that an ocean existed in mars, 3.5 billion years ago. An indirect analysis does not give the definitive answer to a hypothesis. Experimental trials are the best way to find conclusive evidence. But this new data is encouraging for sending new probes to Mars, and even a manned expedition, that can perform experiments on site.

Finding evidence that demonstrates the existence of an ocean in Mars has very important implications for science, and arises new questions, such as:

What kind of process could cause a huge ocean to completely ‘vanish’ from the face of a planet?

If there was liquid water, did life arise as it did on earth?

And most important, Are there fossils of those possible lifeforms buried in the martian surface?

These aren’t easy questions. But they stimulate new ways of thinking, and the sense of wonder needed to start researching. Perhaps the answers to these questions can give explanation to the different hypotheses that we have about the evolution of our planet, and the evolution of life itself.

An abstract for the letter published in Nature Geoscience can be reached at http://www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo891.html

Thank you for reading.