It turns out that some Earth extremophiles, life that has survived here on our planet in extreme conditions, showed tremendous resistance to the space environment. Test subjects included bacteria, algae, lichens, and fungi.

Astrobiologist Jean-Pierre Paul de Vera expressed delightful surprise in seeing the results.  “Some of the organisms and biomolecules showed tremendous resistance to radiation in outer space and actually returned to Earth as survivors from space …. Among other things, we studied archaea, which are unicellular microorganisms that have existed on Earth for over three-and-a-half billion years, living in salty seawater. Our test subjects are relatives of theirs that have been isolated in the Arctic permafrost. They have survived in space conditions and are also detectable with our instruments. Such single-celled organisms could be candidates for life forms that might be found on Mars.”

The results don’t prove that we will find life on Mars, but it does make the search for life on Mars that much more compelling as a driving force for future missions.

Why could there be life on Mars?

Mars contains some of the right conditions for life. The planet has an atmosphere albeit a thin one. But atmosphere and regolith contain carbon, hydrogen, oxygen, nitrogen, sulphur, phosphorus, and water ice. Cyclical methane exhalations have been detected by Martian orbiters.

When the Viking landers in 1976 provided preliminary indirect evidence of life in onboard experiments, it raised expectations that Mars would soon yield its life secrets. But to the frustration of those who study exobiology, subsequent landers and rovers have never detected life but rather conditions that existed in the Martian past that would suggest life once existed there. The Mars of 3.8 billion years ago had a much thicker atmosphere and saltwater oceans and freshwater lakes and rivers on its surface. But it is likely that the smaller size of Mars may have played a role in the planet’s transition from one where conditions for life were evident, to the ones that exist today, a cold, arid planet with a patchy magnetic field incapable of shielding the surface from intense cosmic and solar radiation. If life exists on Mars today it is archaean in form and has adapted to the extremes much the way it does to this date here on Earth.

BIOMEX has given us a baseline for the existence of biology in space and will help in identifying the characteristics of any potential life that could still exist on Mars. When ExoMars 2020, the European Space Agency’s rover that is currently being tested in the deserts of Morocco, it will be looking for life, rather than the conditions amenable to it which Curiosity, Opportunity, and Spirit have sought up until now. The ExoMars 2020 may be the model for other missions to the outer planets and moons including a future rover and lander for Europa in the mid-2020s, and possible future missions to Saturn’s Titan and Enceladus, Jupiter’s Ganymede, and Neptune’s Triton. All of these mentioned above are ice moons with suspected salty oceans lurking beneath their icy crusts.

Why? Because the microorganisms identified in Australian fossils, dating back almost 3.5 billion years, indicate the proliferation of living creatures in the first billion years of Earth history.

As reported in the journal Proceedings of the National Academy of Sciences (PNAS), scientists from UCLA and University of Wisconsin discovered 11 species of primitive microorganisms. Two species displayed photosynthesis-like processes, another generated methane gas, and two others consumed methane to create cellular wall structures. The fossils were found in Western Australia in banded Apex Chert rock formations. These are, to-date, the oldest known fossils of life on Earth.

States J. William Schopf, Professor of Paleobiology at UCLA, the evidence discovered provides “the first data that show the very diverse organisms at that time in Earth’s history …. This tells us life had to have begun substantially earlier and it confirms that it was not difficult for primitive life to form and to evolve into more advanced microorganisms.” Schopf concludes, “if the conditions are right, it looks like life in the Universe should be widespread.”

To find out what made these primitive microorganisms click, the researchers used a secondary ion mass spectrometer (SIMS), separating the carbon in the fossils and measuring the ratio of various isotopes. At the time these microorganisms lived the Earth had not yet developed a significant amount of oxygen. The photosynthesis capability of these microorganisms was probably the catalyst for the chemistry of Earth’s atmosphere to change over the next billion years or so. But the organisms would have had to evolve an ability to deal with the toxicity of oxygen as they expelled it.

Not all scientists agree that what is seen in these images is life. Some believe what we are looking at is very strange minerals that happen to look like fossils.

But if Schopf and his colleagues representing two university research teams are right, they have provided the most detailed study ever conducted on Archaea dating back to Earth’s early history.

Archaea is a classification of living creatures that today are referred to as extremophiles. They live in environments inhospitable to other life on the planet. You can find them on the surface of Earth living in hot springs, or at the bottom of the ocean congregating around black smokers. Or you find them in extreme alkaline and acid environments.

Archaea can also be found in the intestines of ruminant mammals like cows. It is they who contribute the vast amounts of methane to our atmosphere from cow farts.

And we can even find different species of Archaea in plankton.

But for the most part, Archaea thrives where no oxygen is present. That would explain why one would find them in Earth’s past when there was very little atmospheric oxygen.

So if indeed what Schopf and his colleagues have found are primitive life forms inhabiting Earth going back that length of time, it is highly likely that similar processes have led to life happening elsewhere in environments akin to what existed in our planet’s early history.

One cannot help but wonder about Saturn’s largest moon, Titan, with its methane seas. Could it be possible that Archaea are alive and well on Titan to this day, thriving in its extreme cold by digesting and using methane to replicate?

Or in the traces of methane periodically detected by our Mars orbiters, are we measuring the exhalations of Archaea still very much alive on the Red Planet?

Schopf and his colleagues don’t answer the question of more advanced life arising from Archaea. We certainly know it happened here on Earth. That should suggest it likely has happened elsewhere. And given the billions of years between life’s first appearance and today, could intelligent life capable of more sophisticated space travel than us be visiting here after all?

I remain a skeptic about aliens being the likely explanation for UFOs, but I am more than convinced that life populates our Universe, and that intelligent life on some planet or moon circling a distant star is staring up at the night sky and wondering if we exist somewhere in the cosmos.