This is a companion discussion topic for the original entry at https://biologos.org/blogs/kathryn-applegate-endless-forms-most-beautiful/streams-in-the-martian-desert
Dr. McFarland (@benmc) is available to respond to thoughtful, relevant comments and questions.
Evidence of water has been discovered on Mars multiple times over the last several decades – perhaps since the Viking landers of the 1970s. Every time, the discovery makes headlines. I’m not sure why the recent evidence should be considered a ‘triumph’ and ‘another reason for scientists to be excited’. Haven’t most planetary scientists already been fairly certain of water flowing on Mars?
Also, isn’t it a huge leap to go from evidence of water to a discussion of life? So much more than water is needed based on our understanding of life – ozone to block deadly UV, a magnetic field to block other deadly radiation, a stable angle of rotation for climate stability, plate tectonics to help drive evolution, proper temperatures over great periods of time and more. Mars has none of these. Realistically, based on our scientific understandings of life, aren’t the chances that Mars ever had life very low despite the evidence of water?
Two books come to mind – Rare Earth (Ward & Brownlee) and Lucky Planet (Waltham) – that make the case from a completely scientific perspective about the great improbability of life (as we understand it) on any planet and how earth seems to be an incredible convergence of all the right factors.
But this article is different. It is not just about evidence of water flowing in the past. Rather, the surface of Mars is “active with liquid trickles flowing downhill.” Water has amazing properties, and is required for any life. So it isn’t such a large leap to wonder if there might be life on Mars. Even on earth we have found life in amazing places; just look at the extremophiles!
Very interesting and informative. Thanks for posting this.
Tom, To me the big surprise is that this is in the present tense – that there’s exposed, flowing water now. If today’s Martian conditions are put on a phase diagram for H2O it’s far away from the liquid phase (although salts can change that diagram considerably). So I was surprised to see anything.
Since this came out another group has found Martian geological formations that were formed underwater over thousands of years, so there may have been lakes in the past that lasted that long. Still, I think you need millions of years of oceans, not thousands of lakes, for anything complex to come about, and that’s not evident on Mars. Also, it’s pretty much dessicated now.
I think there’s a connection to origin of life because liquid water causes evolution of rocks (this is another idea described well by Hazen) and I think the best chance for understanding a chemical OOL would be if rocks and water worked together (rocks provide a chiral, catalytic surface, water provides the motion and chemical activity). The new phase of matter allows for new chemical possibilities. But we shouldn’t kid ourselves that any Martian “life” could be anything but microbial (I don’t THINK!).
Another book that makes the same general case as Rare Earth (although its focus is different and it comes from a different perspective) is Life’s Solution by Simon Conway Morris, although SCM combines “lonely universe” with “inevitable humans”!
Bottom line = exposed water is special, and we found a tiny bit on Mars today, which means that now we can include early Martian conditions as well as early Earth conditions in possible scenarios for OOL. (This means that elements like boron which are more prevalent on Mars may have played a role.)
I think the Mars results adds to the overall view that water on a rocky planet is not rare but possibly abundant. To me, the big question about Mars is whether it ever had microbial life in the past 4 billion years. When you think of billions of planets in this galaxy alone, simple life seems to be a real possibility someone else besides Earth. If we can find a second place for life beside Earth, it would mean it can be abundant in the universe.
"The sequence of chemical and mineral gifts, reacting in liquid oceans, has culminated in the human brain, the most complex object in the known universe. "
@benmc Dr. McFarland, as a chemist, what can you tell us about the chemical sequence in your assertion above?
The sequence is described in my forthcoming book A World From Dust … but the ideas come from Bob Hazen on Mineral Evolution, RJP Williams on the chemical sequence itself, and Simon Conway Morris on convergence.
You’ll have to forgive me, but I’ll admit I’m extremely skeptical. Although not a chemist, I’ve not heard of any chemical reactions that could bridge the enormous gulf between raw materials (such as amino acids) to any self- replicating molecule that in any way resembles life.
As you know, there have been countless claims made in the past about fanciful ways lifeless chemicals might have somehow arranged themselves into simple life forms. The specific processes and chemicals involved, however, have always remained rather vague to say the least.
Take a look at this:
I’m not sure how long you’ve been reading this type of literature, but I’ve read many such articles and proposals about how life may have arisen from non-life. Do you think this article is special in some way? Usually, these researchers contradict each other in their conclusions from a myriad of other chemicals-to-life schemes.
I suggest you reread the article and count how many times the words “likely”, “seems likely”, “believe”, “our view”, “probably”, etc. appear.
In short, this article is just another dreaming. In reality, there is no known chemistry that can account for the miracle of life on Earth, let alone Mars.
I am certainly no expert in this field. But I do think that these results are a breakthrough in determining how molecules evolved into more complex self-replication molecules. Instead of two independent random processes there was actually only one. RNA and protein folding was essentially the same process with polarity on one side and size on the other side. I thought it was a key result. Only time will tell if it is correct and insightful.
No, it was good science. One piece of the puzzle. A key piece? I don’t know. But it is only a matter of time and research until we know the most likely biochemical physical process that went from simple molecules to complex living combination of molecules.
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