Are There Dead Bodies on Mars?

Are There Dead Bodies on Mars?

The Martian surface exhibits many impact craters, each named after a person, usually a scientist. Crater Vishniac lies appropriately in the Antarctic region of Mars. A famous scientist Wolf Vishniac did not claim that there had to be life on Mars, merely that it was possible, and that it was extraordinary important to know if it was there. If life on Mars exists, we will have a unique opportunity to test the generality of our kind of life. And if there is no life on Mars, a planet rather like the Earth, we must understand why – because in that case, as Vishniac stressed, we have the classic scientific confrontation of the experiment and the control.

The finding that the Viking microbiology results can be explained by clays, that they need not limpy life, helps to resolve another mystery: the Viking organic chemistry experiment showed not a hint of organic matter in the Martian soil. If there is life on Mars, where are the dead bodies? No organic molecules could be found – no building blocks of proteins and nucleic acids, no simple hydrocarbons, nothing of the stuff of life on Earth.

If there is life on Mars, where are the dead bodies? Image: Pretty Elf Close-Up Sketch Drawing © Megan Jorgensen (Elena)

This in not necessarily a contradiction, because the Viking microbiology experiments are a thousand times more sensitive (per equivalent carbon atom) than the Viking chemistry experiments, and seem to detect organic matter synthesized in the Martian soil. But this does not leave much margin. Terrestrial soil is loaded with the organic remains of once –living organisms; Martian soil has less organic matter than the surface of the Moon. If we held to the life hypothesis, we might suppose that the dead bodies have been destroyed by the chemically reactive, oxidizing surface of Mars – like a germ in a bottle of hydrogen peroxide; or that there is life, but of a kind in which organic chemistry plays a less central role than it does in life on Earth.

But this last alternative seems to me to be special pleading: I am, reluctantly, a self-confessed carbon chauvinist. Carbon is abundant in the Cosmos. It makes marvellously complex molecules, good for life. I am also a water chauvinist. Water makes an ideal solvent system for organic chemistry to work in and stays liquid over a wide range of temperatures. But sometimes I wonder. Could my fondness for materials have something to do with the fact that I am made chiefly of them? Are we carbon- and water-based because those materials were abundant on the Earth at the time of the origin of life? Could life elsewhere – on Mars, say, – be built of different stuff?