May 20 2019

New Probe To Look For Life On Mars

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One of the greatest scientific questions to remain unanswered so far concerns the existence of life outside of the Earth. So far the only place in the universe where life has been confirmed in on Earth itself. There is almost certainly life elsewhere, the universe being as big as it is, but we have not confirmed it.

Looking in other stellar systems will not be easy. We will not be traveling to any other stars anytime in the foreseeable future, so what are the options for probing for extrasolar life? We can look for the chemical signatures of life in the atmosphere. Or we can try to detect signals from a technological species. That’s pretty much it at this point, unless that life brings itself or its probes to us.

Our best bet to detect life off Earth, therefore, is to look within our own solar system. There are really only a few plausible locations for life – in the oceans beneath Europa or Enceladus, in the atmosphere of Jupiter or one of the other gas giants, or on Mars. No where else has plausible conditions for life.

Of these possibilities, Mars is the easiest to get to. We have already landed a number of probes on Mars. None of these robots, however, have been equipped with the necessary tools to directly look for life. They did examine the conditions on Mars which could potentially inform the probability of life on Mars, but that’s it. The bottom line of this examination is that conditions are not particularly suited for life as we know it, but does not exclude the possibility of life.

One interesting find is the presence of perchlorates at 0.5-1% in Martian soil, likely widely distributed around the planet. These are reactive molecules containing oxygen, and present both good and bad news for human intentions on Mars.  The bad news is that perchlorates are toxic, and any human presence on Mars will have to deal with the soil itself being a hazard. Extreme measures will be needed to protect astronauts. This is not a deal-killer, but it is a significant technical hurdle.

The good news is that perchlorates are a potential food source for microbes. There are Earth microbes that can eat it for energy. Also, these chemicals can be a potential source for oxygen and fuel.

So are there perchlorate-eating microbes on Mars? We don’t know. None of the NASA probes were equipped to directly answer this question. A new probe, however, is being built by the European and Russian space agencies that will directly investigate this question. The probe is a rover named the Rosalind Franklin – she helped discover the double helix structure of DNA, but died before the Nobel was awarded and is widely felt to be have been underappreciated for her contributions.

On this rover there will be the Analytical Laboratory Drawer, or ALD, which contain three separate experiments designed to look for the signatures of life. This will therefore be the first Mars probe to look not just at the conditions on Mars, but for life itself. Launch is planned for 2020 with an arrival on Mars in 2021.

The probe will also have a drill that can dig down 2 meters into the Martial soil. This is critical because this is where microbes are more likely to be.

The chosen location is the Oxia Planum, which was chosen by an expert panel for various reasons but particularly because it has geological features that suggest the past presence of water.

Detecting life on Mars would be the scientific discovery of the century. For the first time we would know that life exists beyond Earth. But simply discovering the presence of life is just the beginning. Then we need to figure out what relationship, if any, that life has to life on Earth. It’s possible that life on Mars originated and evolved completely independently from life on Earth. If this turns out to be true, that would be fascinating. It will tell us something about the probability of life. We would also get to explore a completely separate biology. What similarities and difference would it have to life on Earth. Would it have DNA or some other molecule of inheritance?

If it is related to life on Earth that is also fascinating. We know that chunks of Earth have been flung to Mars and vice versa, and it’s possible that life could have been seeded from one planet to the other. I don’t think that panspermia, the seeding of life across stellar distances, is very likely, but seeding within one stellar system is possible.

Looking for life on Mars is also critical to any future human exploration and colonization of the planet. If there is life living today on Mars, this presents a significant problem for human visitation. One might argue that we should not risk contamination of Mars with life from Earth. Further, if Mars does have life, then the planet belongs to the Martians, even if they are just microbes. At the very least extreme measures would be needed to avoid contamination.

Also – we may have to abandon any plans to terraform Mars for our own use if there is already life there. We may need to be content living in domes, but leaving the conditions on Mars unaltered.

In any case – this will be an ethical discussion we will need to have if life is confirmed. It will be a good problem to have, for the benefit of the scientific discovery of life. All the more reason to just colonize the Moon. It’s a lot closer anyway.

So keep an eye on this probe. It’s exciting to think that as early as 2021 we may be getting some preliminary data on the presence of life on Mars.

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