Saturday , May 8 2021

If there is groundwater across Mars, where is it safe to land to avoid contamination?

If Mars is a potential home for aliens, can we land safely anywhere without contaminating Earth-born bacteria? A new study has some good news and some bad news. The good news is that Mars is probably completely unpleasant to life. The bad news is that Mars is “probably completely hospitable to life.”

As we continue to roam and challenge the Red Planet, we humans have two basic goals: a) to see if this dusty icy dirt of a world once hosted life, and perhaps even is home to tiny little Martians today, and b ) set up we buy there, eventually building towards a permanent human habitation, and maybe even a once self-sustaining colony.

These two goals are a bit exclusive to each other. As we send more debris from Earth in that direction, we increase the chances of our own bacteria, viruses, and fungi traveling millions of miles and starting their own microscopic colonies on Mars. That life born on Earth will then contaminate all available niches on that planet.

That would be very bad for two reasons. First, life on Earth will begin to compete with any (potential) life on Mars, and we are not in the mood as a species to start the first interplanetary game of survival of the fittest. Second, the presence of microbes on Earth will contaminate all signs of real, real life on Mars. If we see something curling up in the red dirt under our microscopes, we want to know that we are seeing the right deal.

We do not know if there is life on Mars now or if it ever was. We think life may have had a chance there in the distant past, because during the day Mars was full of water: lakes, rivers, streams, oceans, the whole deal. And where there is water, there is a potential home for life.

But Mars today is a totally different story. Planetary scientists continue to debate whether there is any water at or near the surface, and if so, what condition it is in (e.g., if it is super-salty or relatively clean) and how long it lasts.

Knowing where water can be can tell us where life can be. Armed with this information, we can enclose those areas, providing them for exploration without contamination, while engaging in building our colonies somewhere in vain.

According to new research, it seems that we may have more freedom on the Red Planet than we originally thought. Pure liquid water is totally unstable on the surface of Mars: without a significant atmosphere, pure water just evaporates as fast as it forms. But plant solutions are possible, where water is mixed with magnesium perchlorate or calcium perchlorate, either on the surface itself or just below it.

But even those brines do not last long. According to research, brine can last only a few weeks of the year, and even then they are stable for only a few hours. And, I should mention how cold those brines are: -50 degrees Fahrenheit (and about the same in Celsius).

No matter how you cut it, those conditions are not hospitable to all life forms on Earth, even to the most severe extremists. So, Mars seems to be free of Earth-born contamination … but it also means that Mars is probably a dead, frozen world.

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