Astrobiology: The Jovian Planets

If you are a professional scientist interested in astrobiology (exobiology), searching for life in the Universe, your mantra is “follow the water”. If you want to find life, find liquid water first. But liquid water isn’t the total be-all-and-end-all when it comes to finding LGM – Little Green Microbes. Water, based on Planet Earth’s own terrestrial life as the only statistical sample we have, is certainly critical, but so to are lots of other things as we shall soon see.

The Jovian planets, Jupiter and Saturn, including those gas giants further out (Uranus and Neptune) continue to be overlooked as habitable abodes for ET or LGM. The logic of this escapes me as we shall soon see, for the idea that the Jovian planets could in theory harbour life forms as complex as jellyfish or other quasi-aquatic life forms even up to and including the equivalents of Jovian dolphins and whales can’t be ruled out. While Jovian extraterrestrial intelligence (ETI) might be possible, Jovian ETI with technology can pretty much be ruled out, and for much the same reason as to why dolphins and whales here on Earth aren’t a technological species - they can’t build things in the environment to which they have adapted to.

So what’s needed to build us an ET? Well, minimum requirements are 1) appropriate life-as-we-know-it chemicals (CHON – Carbon, Hydrogen, Oxygen and Nitrogen – and of course water or water vapour); 2) a proper comfortable environment for life-as-we-know-it (an appropriate temperature range for liquid water or water vapour); 3) mixing that brings the various inorganic and organic chemicals required into proximity; and 4) an energy source(s) to drive things along, like solar energy does for many terrestrial organisms on Earth.

It’s time to introduce the main players, Jupiter, Saturn, Uranus and Neptune, and those four essentials: CHON, environment, mixing and energy. If there is life-as-we-know-it on these four planets, then we need CHON, we need a proper environment, we need mixing to bring essentials together at one time and place, and we need a source(s) of energy.

One clarification is in order first. Although the Jovian planets are usually called “gas giants”, that is a slight misnaming. While it’s true that relative to Mercury, Venus, Earth and Mars, the Jovian planets are indeed great big balls of gas, they still must have at their centre a solid rocky core, due to, if for no other reason, that over 4.5 billion years of their existence, asteroids, maybe even small planets, meteors, dust, and comets have all slammed into them. The rocky stuff, ultimately, must sink to the bottom forming a solid heavy element core. With that clarification made, let’s see what there is to be speculated upon.  

CHON: Any biological organisms that have been and are are being provided with appropriate CHON. Jupiter, Saturn, Uranus and Neptune have atmospheres rich in carbon, hydrogen, oxygen and nitrogen compounds.  The CHON box is ticked on all four Jovian planets. With respect to CHON, there are probably all sorts of way more complex organic molecules present in the four Jovian atmospheres but in such relatively small quantities that are dispersed widely and deeply so as to have escaped detection to date from our relatively faraway fly-by and orbiting probes. 

Suitable Environment: All the gas giants have a Goldilocks environment (at least in places). There’s no disputing that the cloud tops are bitterly cold; the deep interiors are way too hot. But, that alone suggests that there will be a Goldilocks area in-between, probably extending vertically for hundreds of kilometres, and extending as well horizontally around the globe. That volume, given their large size (relative to Earth), comprises a lot of Goldilocks territory. The habitable environment box on all four Jovian planets is therefore also ticked.

Mixing: Since Jupiter and company have very hot interior cores and the top of the atmospheres are extremely cold, and since heat rises and cold descends, that alone suggests that mixing in their primarily gaseous/quasi-fluid body must take place. Quite apart from that, all one needs to do is view time-lapse photography of their upper atmospheres to see all the turbulent motion that takes place. A tranquil pond the gas giants aren’t. The mixing box also gets a tick.

Energy: The Jovian planets all have an abundant energy supply, albeit not photosynthesis. Solar energy is highly unlikely to drive any Jovian biology because their atmospheres are very thick, and just like with our terrestrial oceans, things get very dark very quickly as one descends. However, chemical energy (chemosynthesis) is a strong possibility, like that which drives terrestrial hydrothermal vent communities. Then there’s infrared (instead of visible) radiation. Jupiter and company radiates much more heat that it receives from the Sun, the heat being slowly radiated outward from their original quota of primordial heat energy largely stored in the core of the planets.  The Jovian planets are fantastic places to visit if you’re fond of thunderstorms. Lightning really lights up their skies. Lightning is a prime source of energy for driving chemical reactions. Translated, all up, the gas giants are awash with potentially useful energy sources to drive any local biology. The available energy supply box is ticked too.

I suggest therefore that the soupy atmospheres of the giant planets have all the fundamentals required not only for the origin of life, but long-term habitability. There also have been over four and a half billion years for interesting biological happenings to have occurred. In addition, there’s a lot of volume in each of the Jovian planets for interesting stuff to happen in. The odds of things all coming and getting their act together in a small pond is small relative to a large soupy atmospheric ocean.

That all four Jovian planets have evolved life is problematical; that at least one has become a biological abode is much more certain, IMHO. Throw in one or more of their satellites like Europa and Enceladus that offer a liquid water ocean environment – well that’s a bonus. On top of all that, the Jovian planets have the highest gravities apart from the Sun. Now that means they suck in more than their fair share of other solar system debris – like comets and asteroids. Now comets and asteroids, the leftovers of that initial stuff out of which our solar system was made, also tend to be rich in CHON. No doubt they, via impacts with the Jovian planets, have contributed their CHON bit to the already potential suitability of those abodes as habitable abodes.

So what sort of Jovian life might we expect? On Planet Earth there is a sharp boundary between the atmosphere and the hydrosphere. On the four Jovian planets one just slowly merges into the other as one goes deeper and deeper. Terrestrial but airborne microbes, bacteria, germs, and other single-celled beasties, and their marine equivalents, like plankton and other unicellular critters, occupy both environments and are happy little campers. There’s no reason for there not to be Jovian equivalents that ‘swim’ and multiply in whatever region of the various four varieties of Jovian atmospheric ‘soups’ that have a comfortable, Goldilocks temperature regime. Of course that Goldilocks region could extend over hundreds of vertical kilometres in range. Some organisms might be better adapted to the thinner cooler upper regions; others to the murkier but warmer depths. Regardless, it gets dark fast so eyesight in the visible range of the electromagnetic spectrum might be problematical. Of course phosphoresce, not all that uncommon in marine life here on Earth, can’t be ruled out of course.    

If simple life forms originated and evolved on Jupiter, Saturn, Uranus and/or Neptune, then more complex and far larger ‘marine’ and ‘aerial’ life forms might be present too. Their trick, in order to stay in the Goldilocks zone, will be to have evolved the capability to maintain neutral buoyancy, but also to be able to rise if turbulence pushed them downwards towards greater heat; be able to sink if currents push them too high where chill factors come into prominence. So ‘gas bag’ floaters or ‘fish’ with ‘airbags’ might be possible Jovian alien life-forms. There’s no reason such critters couldn’t have developed a relatively sophisticated degree of intelligence. It’s possible to have intelligence without the means of developing technology as our whales and dolphins and even the humble octopus demonstrate.

The fly in the ointment is that our on-site investigation is going to prove to be an extremely daunting technological task, one that most certainly won’t happen in the next several decades – probably much longer. In the short term, the best bet is to use remote spectroscopic analysis of the atmospheric ‘surfaces’ or actual surfaces (in the case of the satellites) to identify biological signatures – compounds that just cannot be accounted for by non-biological processes. An example would be the pinkish-red areas on Jupiter’s moon, Europa. 



Extraterrestrialism: Part One

If asked the question about your ultimate origins, you might reply that you were of this or that nationality, perhaps with ancestry from this or that other place. Perhaps if you’re a bit more clued you’d say “Africa” as the birthplace of the human race. If you’re really cluey, you might say the oceans, the undoubted place where life itself got its start. But no doubt, no matter what, you’d say you were “terrestrial” – of this Planet Earth. Alas, you’re still not cluey enough. You’re extraterrestrial. We are the aliens, directly and indirectly.

Origin of the Universe

* Once upon a time there was this Big Bang.

* Since we are a part of the Universe, and since the Universe had an origin (the accepted standard model being the Big Bang event some 13.7 billion years ago), that alone of necessity means we have an extraterrestrial legacy since everything that makes you, you was born in that event, thereby in a manner of speaking making you 13.7 billion years old!

Origin of Our Stellar Solar System & Earth

* As it was in the beginning, well so too did our Sun and Planet Earth have a beginning.

* We are Star Stuff. Our solar system, our Sun, the planets, including Earth, were all formed out of the remains of extraterrestrial gas, dust and debris from older stellar systems, scattered to the four interstellar winds by supernovae explosions, over four and a half billion years ago. Thus, that too alone, no matter which way you slice it, means we (as beings part and parcel of our stellar system) are extraterrestrial in origin.

Origin of Life

* The terrestrial origin of life may have happened within that petrii dish/test tube called Planet Earth - Or maybe not. IMHO it happened way too quickly and way too soon post Earth’s formation to probably have been a solely terrestrial happening. There’s an alternative called panspermia which expands both the time and space available for life’s origin by many order of magnitudes.

* Panspermia is the idea that Earth was seeded by cosmic spores or microbes that were expelled from some other planetary abode in some other stellar system and drifted across the gulf of space. An incredibly tiny fraction of these cosmic spores lands on suitable planetary environments, where they survive and thrive and evolve. Our Earth was one such place for their lucky landing. It’s akin to a plant producing millions of spores – 99.999% of which fail to land on fertile ground; but that tiny fraction that does is all it takes to keep the species keeping on keeping on. 

* Ballistic panspermia is a slight variation on traditional panspermia in that the microbes or spores are inside the protective covering of a solid object – dust or tiny rocks, even massive rocks. These, alone with their microbial passengers get blasted off home turf by incoming ballistic objects (impacting meteors), escape their home planet and a few eventually, by chance land on another suitable abode. That Mars rock, ALH84001 that caused such a stir several years back is one such example of a potential case history of ballistic panspermia.

* Directed panspermia is yet another variation on the theme, only in this case there’s intelligence behind the scenes, either sending out canisters of microbes willy-nilly in a shotgun manner, and/or directing that canister specifically at a chosen target.

* The upshot is if terrestrial life’s origin was via a form of panspermia, then we humans, being a species of terrestrial life, ultimately had an extraterrestrial origin. If a Mars rock full of microbes impacted Earth billions of years ago, well, we might be the Martians transplanted from the fourth rock to the third rock from the Sun. Perhaps our origins were even farther a-field. Perhaps some cosmic gardener planted life here billions of years ago, maybe even stuck around to fertilize, cultivate, prune, and weed that garden. 

Extraterrestrial Life, Intelligence, Civilization and Technology: The Fermi Paradox

* The Fermi Paradox can be summed up simply enough by pointing out that as long as you assume the existence of at least one other technologically advanced extraterrestrial civilization with the same sorts of ‘boldly going’ drives as we humans have (i.e. – plain old curiosity, the what’s on the other side of the hill, if nothing else, then just as humans explored and colonized Planet Earth in a tiny fraction of the Earth’s existence, technologically capable extraterrestrials would have explored and colonized the Milky Way Galaxy in a tiny fraction of its existence. In the case of humans, we don’t need to ask “where is everybody?” We’re everywhere. In the case of ET, we do ask “where is everybody?” They should be here. Scientists say they’re not, never have been, and thus have to explain the paradox. On the other side of the fence, those who see evidence in those ‘ancient astronauts’ and in UFOs have no paradox with which to have to come to terms with.

* The ‘Gods’ arrive. Very few people today would try to defend the position what in the vastness of the cosmos we, human beings, are the proverbial intelligent ‘IT’ within that cosmos. Since we are the new boys on the block, having only existed as a unique species several hundreds of thousands of years at best in a Universe that’s 13.7 billion years old, the odds are pretty good that our intellectually cosmic superiors are out there. Now on the likelihood that at least one such superior extraterrestrial intelligence will boldly go and explore the cosmos, let’s define ‘cosmos’ and restrict that term to our ten billion years old Milky Way Galaxy, the time it would take that extraterrestrial intelligence to explore every nook and cranny of our Milky Way Galaxy is but a tiny fraction of the age of our galaxy. By analogy, Planet Earth has existed four and a half billion years; yet as noted above our 100,000 plus year old species crawled all over it in real quick-smart fashion, as did the bacteria, plants, insects, and other life forms as well. Translated, since there’s nowhere to hide Planet Earth from the ‘I spy with my little eye’ aliens, we’ve been found! The extraterrestrials have arrived, not yesterday but millions of yesterdays ago. And since Planet Earth is a hospitable bio-friendly place, one with a pretty unique property – a biosphere – they decided to stick around and set up camp. Because these beings are high-tech, and because any sufficiently advanced technology is something supernatural to any sufficiently lower technological civilization (like us), that supernatural quality gets interpreted as beings who ARE supernatural – deities or ‘gods’ – not interpreted by the great unwashed primitives as flesh-and-blood extraterrestrials. Our cultural mythologies, worldwide, are full of references to ‘star beings’; ‘guardians of the skies’; ‘sky gods’; ‘gods in the heavens’ and gods who come from the stars or who are associated with specific stars and constellations, most notably Cygnus, Sirius and Orion.

To be continued…