Life Elsewhere in the Universe: How we define life and will we know it when we see it?

This is something that I have given a great deal of thought to and I have often responded to the frequently used phrase ” life as we know it” with “how about life as we don’t know it?”

A recent article in the Nautilus by Conor Feehly entitled ” Will we know alien life when we see it?” got me thinking about it again with a fresh new perspective, given the fact that with new developments and technology like the James Webb Space Telescope which have accelerated the search and the humanity’s passion for answering the time honoured question: “ are we alone “? It seems that we’re closer than ever to finding “life” on cosmic shores other than our own. I should point out here that intelligent life is rather obvious and wouldn’t require this kind of existential debate. So, if we do ever receive a signal from an ET civilization or, if someone drops by to say “hello” –there won’t be any debate as to whether they are alive or not 🙂

No –this is for that much grayer area in between where “life” could be anything from bacteria to –well—something that we don’t recognize. And that is the whole point –will we recognize (and more importantly—respect) that life when we see it? That definitely seems to depend on whether that life meets a variety of definitions and conditions–all, of course, defined by us. Which is where it starts to get problematic. Who are we to define another life form, which could be something that we cannot even begin to imagine.?

The Nautilus article give us some good information to start with and reminds us that there is a significant philosophical issue here as well as scientific. One thing that Feehly mentions that particularly resonated with me is Carl Sagan’s assertion is that our definitions of life are “too constrained by the characteristics of life as we know it. A single example of ET life could change everything.” My thoughts exactly and when one is going to agree with someone, it may as well be the iconic Carl Sagan who happens to be a personal hero of mine. 🙂

Feehly’s article gives a basic overview of the biology that would comprise life as we know it –things like “movement, respiration, growth, reproduction, DNA ” etc, most of which was over my head. But he does include a quote which I found especially interesting, and I believe, points us in the right direction of where we need to go as we grapple how to deal with this issue. In a recent white paper submitted to the Planetary Science and Astrobiology Decadel Survey 2023-2032 of the National Academies, a group of scientists from NASA, SETI, and various universities around the world, outlined a way forward. They wrote:

” The probability that life in the universe would share a biochemical ancestry with life on Earth quickly diminishes the further from Earth we explore.”

They go on to say that that it is imperative that that our future life detection strategies target universal biosignatures. Which appears to be the direction we are going, with the use of spectroscopy to analyze what chemical elements are present in the atmosphere of an exoplanet that can only be produced by organic life. The images, including images of exoplanets, that are being produced by the James Webb Space Telescope are remarkable not only for their staggering beauty but also for their jaw dropping depth in showing us just how unfathomably large and diverse this universe is. (more on the JWST in my next post). We cannot and must not be bound by the limiting definition of “life as we know it” and these directions and guidelines of being prepared for a a broader definition of “life” are timely indeed as that moment may be here sooner that we think.

I don’t have the answers—just more questions but I believe that thinking about whether we will recognize “life ” when we see it is a good place to start. It may not look anything like us or the “little green men” that we are relentlessly sold in science fiction. It may not look like anything we can imagine. It may not have the physical characteristics that we associate with being “alive “. But we must keep an open mind and more important, we must respect whatever life we encounter.

Would love to hear your thoughts on this.

M.A.N.

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