Astrobiology: It’s Life Jim, But Not As We Know It: Part Two

Terrestrial life, extinct and past; or alive and present is amazingly diverse – in appearance anyway, but also in the environments they inhabit and the abilities they have to survive and thrive. But under the skin, our fundamental biochemistry, be you T-Rex, or be you a maple tree, or be you a bacteria, or be you, you, well you’re all as closely related as makes no odds. Extraterrestrial life will also be amazingly diverse – in appearance. However, the fundamental biochemistry that makes them, them, might be equally diverse relative to what makes you, you.

Traditional Hollywood fare, when it comes to envisioning aliens, tends to take the cost-friendly option and place actors in strange looking, but humanoid form costumes and associated makeup. Or, forget the costumes, maybe they just give the actors pointed ears or paint a few dots on them or wrinkle their noses! The question remains, will real, as opposed to Hollywood’s version of intelligent alien beings be humanoid, or something quite less than humanoid? At a more fundamental level, will the aliens, regardless of appearance, be composed of the exact same sorts of bio-friendly bio-elements and bio-molecules as we (we being terrestrial life forms collectively) are? Will our neighbors among the stars resemble life-as-we-know-it or life-not-as-we-know-it? And what really counts as life-not-as-we-know-it? Is it appearance, environmental habitat, abilities or is it chemistry?

Continued from yesterday’s blog…

So, here’s just one logically possible outward description of an advanced extraterrestrial intelligent life force with technology. In basic outline, I imagine a centaur-like structure, a being with four locomotion stubby tentacles ending in splayed out thick pads for ‘feet’. There are also four relatively long manipulative tentacles emanating from roughly chest height. Two of the tentacle’s tips manipulate objects in much the same way as one hand’s finder and opposable thumb manipulate objects. The four tentacles in total equal the manipulative abilities of our two hands. There are four eyes on elevated stalks at the top of the ‘head’ giving a 360 degree field of view. Any two adjacent eyes give a stereoscopic view – depth perception – covering 180 degrees, though it can see farther into the infra-red relative to ourselves because it’s parent star is cooler and radiates more energy in the infra-red than the visible part of the electromagnetic (EM) spectrum. The body has a protective carapace and our being can withdraw its ‘leg’ and ‘arm’ tentacles inside if necessary like a turtle; ditto the soft ‘head’ structure, which has – you guessed it, four ears. Over all, the ‘skin’ is akin to thick tough leather. The being’s CPU ‘brain’ is located deep within the central body, not in the ‘head’, and so is well protected. Breathing is pretty much the same as ours – it has lungs. Ditto the digestive system. Like ourselves, it’s a carbon based life form and requires the same sorts of water intake as we require. The alien is native to a slightly lower gravity world than ours; its land based, and has a size roughly that of a large terrestrial dog or small sheep. There’s no tail.  

Apart from my quickie off-the-top-of-my-head imaginary creation, well, you also gotta give some, and I stress some, Hollywood and sci-fi writers’ full credit for at least trying to think a bit outside of the box. The central question remains the biochemistry one, not the appearance one. Terrestrial life forms are so diversified in appearance that it’s difficult to imagine any pattern, any symmetry (or lack of same) that hasn’t already been experimented with. However, physical appearance diversification is yet united in that diverse terrestrial life forms have collectively just a single overall biochemistry. Microbe or man; virus or vampire; plant or platypus; we’re all at the biochemical level near clones. So, we’ve had the diversification in outward appearance; might there equally be a diversification in what makes life, well, life?

But first, life has to have some abilities, and life has to exist within an environment that’s fit for, well, life. Both abilities and environments go way beyond life-as-we-know-it, if by that we restrict life-as-we-know-it to the very everyday familiar life forms that we perceive around us – even then, surprises abound.

Abilities: When it comes to special abilities relative to ourselves, well fish gotta swim (but so do dolphins, a paramecium, squid, penguins, some turtles; even we humans make a rather feeble go at swimming but we’re not in the same league, far less the same ballpark as fish, etc.). And birds gotta fly (but so do bats and many insects; humans are natural flyers too – as long as it’s straight down). Clearly lots of organisms can move faster than we can. Many organisms have had abilities that have enabled them to survive for multi-millions of years; billions if you include microorganisms. We’ve got a long way to go before we start making it in that ‘Guinness Book of Records’. Your dog can hear higher frequencies than you; your cat has a better sense of smell; many birds have sharper vision and many organisms can ‘see’ parts of the electromagnetic spectrum that we can’t.

But, not to worry, at least we tend to come top of the pops in the I.Q. category! Now the natural question is, what sort of evolved abilities or capabilities might intelligent aliens have that haven’t been thought of in anyone’s philosophy, apart from perhaps being mental giants and putting us to shame in that I.Q. category? 

Environment: When we think of the typical environment that life finds itself in, we tend to think of our own traditional environment, one that has a fairly narrow temperature range; predictable alternating daylight and darkness intervals; one relatively free of harmful radiation; a fairly narrow pressure range; also a very narrow range of an environment that’s not too acidic, not to alkaline; a near constant atmospheric composition, etc. We don’t often tend to think that life in general, terrestrial life in particular can survive, even thrive outside what’s comfortable to us. How wrong we are if we think that! Relatively few complex organisms exist in extreme environments, though examples would fill many an essay all by itself. We all know about animals that can live in Earth’s Polar Regions and in her ultra dry and hot deserts. We know that fish survive at the high pressure, eternally dark abyssal depths, and that some fish can bury into mud and cocoon themselves from drought for extended periods. Still, that’s peanuts compared to what some microorganisms can achieve. Without doing an exhaustive survey, you’ll find microbes surviving and thriving: high up in the atmosphere; kilometers beneath the surface of the earth; inside your digestive system; inside rocks; in battery acid equivalent environments; in extremely high saline environments; in extreme alkaline environments; in total darkness; in pressures that would crush you like an eggshell; in boiling water; in the near absence of water; in temperatures way below freezing; in toxic sludge; inside nuclear reactors; in environments totally free of oxygen. Some microbes can survive (but not thrive in) exposure to near absolute zero temperatures and the vacuum of outer space. The upshot is that the range of non-terrestrial planetary environments where we might detect, at least relatively simple life, has expanded to just about anywhere and everywhere. 

To be continued...