The Rare Earth Hypothesis: Part One

If the Search for ExtraTerrestrial Intelligence (SETI) is a viable experiment and not a waste of time; if UFOs and ancient astronauts are facets that help document the existence of extraterrestrial intelligence, then the very existence of an advanced extraterrestrial intelligence with technology has to be plausible in the first place. Unfortunately, it’s a long hard road to get from inorganic chemistry through to E.T. and there are many possible bottleneck hurdles that have to be overcome before the one evolves into the other. Goldilocks factors – not too this, not too that, but just right – have to be with you every step of the way. IMHO the major bottlenecks are the transition from unicellular to multicellular life and the evolutionary development and use of technology.

It’s been pointed out by others, and based on my readings I tend to have to agree, that astronomers (physical scientists) tend to be much more optimistic and supportive of the notion that advanced life forms in the Universe (extraterrestrial intelligence) are a dime-a-dozen relative to biologists (life scientists), who hedge their bets and who it must be said are presumably better qualified to pass judgments. So, taking things from a more biological perspective, what’s what?

For starters, our Universe is a Goldilocks Universe in that the fundamental laws, relations and principles of physics unite in such a way as to be ultimately bio-friendly. If the Universe wasn’t bio-friendly, we wouldn’t be here to comment on that. That’s not to say however, in relative contrast, that many (most) parts of the Universe aren’t overly bio-friendly. You’d be hard-pressed to survive and thrive in the depths of a stellar core, heading down a Black Hole, vacationing on the surface of a White Dwarf or in the hard vacuum of space itself.  So, overall the physics of the Universe displays the physics of a Goldilocks Universe, but actually very few addresses within an overall Goldilocks Universe are really, by our definition, Goldilocks. However, starting with bio-friendly physics, where do we go from that point? Well, physics begat inorganic chemistry. That’s step number one, and clearly that’s easy because there’s an awful lot of inorganic chemistry in our Universe.

Going from inorganic chemistry to organic chemistry isn’t difficult either. Interstellar space is full of dust and gases made up of organic chemicals; ditto many of the planets and moons within our solar system (i.e. – Titan, a moon of Saturn) have organics being part and parcel of their composition, and comets, asteroids and meteors too can contain organic compounds.

Judging by how quickly organic chemistry turned into biochemistry (the origin of life) on the early Planet Earth, it’s not difficult to generate simple proto-cellular to unicellular life forms if the conditions (adequate energy, temperatures, environments) are Goldilocks conditions.

Yet life, even microbial life, is still very, very complex (try making a microbe from scratch if you doubt it). The fact that life arose from scratch on Earth within a very, very short span of geological time after the planet formed is a bit suspect IMHO. But what if Earth were seeded by microbial life forms already in existence from space (or deliberately seeded by extraterrestrials as the Nobel Prize winner Francis Crick has proposed)? Now I realize that just puts off the origin of life question to another time(s) and place(s). However, given the vastness of the cosmos is far greater than that of our finite globe, and given that the cosmos existed for vastly longer periods of time before our sun, solar system and home planet came into existence, such additional time and space easily turns the improbable into a near certainty. And once established somewhere, then life could spread throughout that time and space, until it reached our young planet.

Earth arose billions of years after the universe and our galaxy had evolved, ample time for life to have arisen elsewhere, and seed the early Earth. This is the concept of panspermia. We know that comets, meteors, and the cosmic dust of outer space are chock-o-block full of complex organic molecules. We know that simple terrestrial life can survive the outer space environment if suitably shielded – and it doesn’t take much to do the shielding. We know that surface bits from planets/moons can be ejected into space, carry a cargo of microbes, and land on another planet, even eons later with the microbes still viable. Of course 99.999% of all such microbial life will be doomed to forever wander in space or crash onto a cold, surface of a planet with no atmosphere or water, or plunge into a star, etc. But, sheer numbers will insure that now and again some microbes will land on a hospitable abode and be fruitful and multiple and evolve. The interesting bit is that if then, then now. And thus panspermia will be happening today. Certainly some meteorites which have impacted Earth have inside them ‘organized elements’ suggestive of microbial structures – the Murchison Meteorite from Australia is one such stone. The problem is terrestrial contamination as there are often lengthy time periods between their fall and subsequent discovery. As an aside, if Fred Hoyle & Chandra Wickramasinghe are correct (and I believe they are), microbes (bacteria and viruses) impacting Earth today are largely responsible for some select or various disease epidemics and pandemics, past present, and no doubt future.

On Earth, microbes rule, OK? The biomass of all the bacteria, etc. put together easily equals the biomass of every other multicellular plant and animal added together. And microbes can live in environments where multicellular critters fear to tread and often can’t: from the coldest terrestrial environments, up to the near boiling temperatures, from deep underground to the heights of the atmosphere, from inside water-cooled nuclear reactors and the interior of rocks, to intensely saline, acidic and alkaline environments, to ecosystems where the sun never shines, like the abyssal depths.

They can even survive outer space. Bacteria survived on the surface of the Moon – on Surveyor Three. This was possibly the most significant discovery of the entire Apollo Moon program and it hardly even rated a mention. Astronauts from the Apollo 12 mission brought back to Earth parts of the unmanned Surveyor Three Lunar Lander. Terrestrial bacteria on those parts survived the lunar vacuum, solar radiations (UV, etc.), the massive temperature extremes, and lack of water and nutrients. Experiments since then in low earth orbit have confirmed that given just minimal shielding, bacteria can boldly go!

You’d be aware of how difficult it is to totally sterilize something, be it hospital equipment or a spacecraft bound for a Martian landing. They’re tough – have you ever read about a mass extinction event where a bacterial species, unlike say the multicellular dinosaurs, went poof? Microbes are easy to transport. They can be blasted off the surface of the Earth, shielded from radiation by the debris, and survive to land on another world and be fruitful and multiply. There’s little doubt that somewhere way out there, terrestrial bacteria have hitched a ride to the stars, bolding going where lots of microbes have gone before! Translated, I firmly expect that the universe is teaming with life in all sorts of places. The less than glamorous catch is that LGM is not going to stand for Little Green Men, but Little Green Microbes.

To be continued...