Mythologies of the Solar System: Part Three

The names of the moons, planets and of course the Sun itself are not just household names un-associated with anything but these celestial bodies, but bodies usually named after selected characters from ancient Greek and Roman mythology. There are tales to be told about them; some fleshing out to do. These are just a few of the highlights.

The planets of the solar system are named after gods and goddesses and are known by their Roman, not Greek names. Here I’ll put the Greek equivalents in brackets afterwards. The satellites of these planets for the most part tend to be the Greek names associated in one form or another with the parent body or the god/goddess in question. Moons (and major asteroids) are identified with an asterisk.

Continued from yesterday’s blog…

MYTHOLOGY AND THE OUTER SOLAR SYSTEM

SATURN (Cronus) was one of those first generation Titans, offspring of Gaia and her son Uranus. He mated with Rhea, and produced from that union the original half-dozen gods and goddesses that would eventually become the Olympians. But the transition from Saturn’s offspring to become the rulers of Mount Olympus was an epic that could just about out-epic anything Hollywood has ever done. Saturn is known for two things in particular – castrating his daddy and snacking on his kids - Yum, yum. 

*Dione is a very obscure goddess who may have been a Titan or a Nereid or an Oceanid. Her name seems to be a feminine form of Zeus, and that brings in the alternative version of the origin of Aphrodite – a traditional birth via the union of randy Zeus and Dione (whoever she was). At least she’s now immortalized as a satellite of Saturn.

*Enceladus was one of the Gigantes. The Gigantes were offspring of Gaia, fertilized by the blood/semen of her son and lover Uranus who was ultimately castrated by Cronus (a son of Gaia and Uranus back when he had his private parts intact). In the Gigantomachia (the battle between the Olympian gods and the giants), Athena deposited Enceladus under Mount Etna and the fire and brimstone breath of Enceladus accounts for that volcano’s well, fire and brimstone. This is another abode thought as a possible site where alien life forms might one day be discovered.

*Hyperion was a Titan god, born of Gaia (Gaea) and her son, Uranus. He would become an early god of the Sun.

*Iapetus was another Titan god, born of Gaia (Gaea) and her son, Uranus. He would become the father of Prometheus, who ultimately is remembered for stealing fire from the gods and giving it to mankind.

*Janus was the Roman god of beginnings, doorways, entrances, gateways, etc. and is depicted with two faces, one each facing forward (to the future) and the other backward (to the past). January, the beginning, is named after him.

*Mimas, like Enceladus, was one of the Gigantes of Greek mythologies. Like the other giant sons of Gaia and Uranus, Mimas had serpents for legs and was born fully armored. Mimas was slain by Hephaestus during the war against the Olympians by a volley of molten iron.

*Phoebe was a Titan goddess, born of Gaia (Gaea) and her son, Uranus. Phoebe is identified as an early moon goddess. In another context, the goddess Artemis sometimes was associated with an alias of Phoebe. Finally, Helen of Troy had a half-sister Phoebe.

*Rhea was another Titan goddess, born of Gaia (Gaea) and her son, Uranus. She married Cronus (Saturn) and from that union was born what ultimately became the original half-dozen Olympian gods and goddesses. Cronus, out to eliminate potential future rivals, swallowed the first five of these kids, but Rhea tricked him when it came to the sixth and last, Zeus. She spirited Zeus away to Crete to be raised, and tricked Cronus into swallowing a stone disguised as the baby Zeus.

*Tethys was yet another Titan goddess, born of Gaia (Gaea) and her son, Uranus who would become the most ancient goddess of the sea.

*Titan is the largest moon of Saturn, a moon of interest to astrobiologists, and the only natural satellite to have an extensive atmosphere. In fact, Titan is larger than the planet Mercury and way lager than our own satellite, Luna. The mythology connection is that the original dozen Titans (some of which are named satellites of Saturn) were one of a set of offspring between Gaia and Uranus. Among the second generation of Titans are several household names like Atlas and Prometheus. They were overthrown in the Titanomachy (The War of the Titans) by Zeus and his fellow Olympians. 

URANUS (alternative spelling Ouranos) was the original sky god, the son, via parthenogenesis, of Gaea (Gaia) who shacked up with mum to produce all manner of deities, including monstrous ones. He’s known for having his privates sliced off by one of their Titan offspring, Saturn (Cronus). Saturn in turn got done like a dinner by one of his offspring, Jupiter (Zeus) but that’s another story.

*Ariel, Miranda, Oberon, Titania and Umbriel, the five major moons of Uranus, were named or chosen from the names of characters from the works of Shakespeare and Alexander Pope and thus, unfortunately, have near bugger-all to do with traditional Greek and Roman mythology. Bummer, as that spoils some potentially good stories relating back to and involving the parent god, Uranus.  

NEPTUNE (Poseidon) was the god of the sea, one of the original half-dozen Olympian gods and goddesses, brother to Zeus, Hades, Hera, Hestia and Demeter. All of Neptune’s known 13 satellites are named for Green and Roman water deities or groups of minor water gods. The major two are Nereid and Triton.

*Nereid – the Nereids (plural) were nymphs of the sea, the 50 daughters of the Mediterranean Sea god Nereus. Among the famous of the Nereids – goddess all – were Thetis (mother of Achilles), Galatea and Amphitrite (who married Poseidon). 

*Triton was another sea god, a son of Poseidon and the Nereid goddess Amphitrite, a nymph of the sea who became Queen of the Sea when she wed Poseidon. The typical depiction of Triton is that of a merman – human head and torso; one or two fishy (or maybe dolphin) tails. He too has a trident and a conch shell which when blown can calm the stormy waves. Like father, like son, Triton also had a bit of an eye for the ladies, especially beach-babes. Triton favors in a positive light for assisting Jason and the Argonauts in their saga. 

PLUTO (Hades) was god of the underworld. In the Greek version, Hades (the god) administered Hades (the underworld), so the name of the ruler and the place ruled were one and the same. Within recent times, Pluto was officially downgraded from planet to dwarf planet status, which made a lot of traditionalists very unhappy.

*Charon was the son of Erebus (the god of underground darkness) and Nyx (goddess of night), who played the role of the ferryman who rowed the newly deceased across the River Styx to Hades, the underworld. As a reward, or a fare, he got a coin in payment – no coin, no crossing. The parentage and place of employment are ideal for a satellite so far out from the Sun.

*Hydra (discovered in 2005) was named after that famed beastie slain by Hercules as one of his dozen labors in Greco-Roman mythology. Hydra was one of numerous monstrous offspring from Typhon and Echidna, themselves monsters. 

*Nix (a deliberate alternative spelling of Nyx) was a Greek goddess of night, one of the original deities conceived from the original state of the universe, Chaos. Nyx was the mother of Charon. Like Hydra, Nix the satellite was discovered in 2005.

ERIS is another dwarf planet, a trans-Neptunian object even larger that Pluto discovered in 2005. In fact it’s the most massive of all dwarf ‘planets’ in our solar system, even though it’s three times farther removed from the Sun than Pluto. Eris is a Greek goddess, the personification of strife and discord.

*Dysnomia in mythology is the daughter of the goddess Eris.   

NEMESIS (Fortuna was the Roman counterpart) was the asexual product of the goddess Nyx (night) and she was the goddess of retribution and agent of vengeance. Originally she was just one who dispensed fortune or luck without predetermined rewards or punishments, but morphed into a goddess of justice. The ‘Wheel of Fortune’ is thus associated with her. The celestial Nemesis is a hypothetical dwarf star binary companion to our Sun, a faint stellar object that has an extreme elliptical orbit that beings it close to the solar system once every 26 million years, which when extrapolated backwards, was useful in explaining periodic mass extinctions on Earth. Alas, all searches for this dwarf companion star have turned up negative, and the hypothesis is pretty much in scientific limbo today. 

Jovian Life: The Moons Versus the Planets: Part Two

In our solar system, the planets are divided between the inner terrestrial planets (Mercury, Venus, Mars and of course the Earth) and the outer gas giants, collectively called the Jovian planets (after Jupiter, but including Saturn, Uranus and Neptune), which along with their many moons form the Jovian system. Since it’s easier to look in our own planetary backyard neighbourhood first for alien life, there’s been much speculation about what pieces of solar system real estate, if any, might be suitable abodes for extraterrestrial life. While Mars has always been top-of-the-pops, a once heavily favoured Venus fell by the wayside a while back, only to be replaced with a few bits of real estate somewhat further out. It’s those “somewhat further out” bits of real estate that are now under-the-gun. While most speculation is on selected Jovian satellites, I put the accent on the parent bodies.

Continued from yesterday’s blog…

Now on to the major players! 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. 

Jupiter: CHON: Jupiter, a gas giant, is composed mainly of molecular hydrogen (the H in CHON) and helium (much like the Sun’s composition and in roughly the same ratios). There are certainly ammonia (probably as ice crystals) and ammonia compounds (like ammonium hydrosulphide) in the atmosphere, adding nitrogen (the N in CHON) to the mix. Methane (which contains the C in CHON), as does the carbon contained in carbon dioxide and carbon monoxide are also present in the upper atmosphere. Water vapour (the O in CHON) is certainly present, even though in small proportions relative to hydrogen and helium. The colourful bands of latitude could easily be suggestive of complex, even organic chemistry involving not only CHON but sulphur and phosphorus and other trace elements. The upper atmosphere of Jupiter contains small amounts of simple hydrocarbons such as ethane and acetylene, which forms from methane under the influence of the Sun’s ultraviolet radiation and the highly charged particles incoming from the Jupiter’s magnetosphere.   

Jupiter: Environment: There’s no disputing that the cloud tops are bitterly cold; the deep interior is 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 Jupiter’s size, comprises a lot of Goldilocks territory. 

Jupiter: Mixing: Since Jupiter has a very hot interior core and the top of the atmosphere is extremely cold, and since heat rises and cold descends, that alone suggests that mixing in Jupiter’s primarily gaseous/quasi-fluid body must take place. Quite apart from that, all one needs to do is view time-lapse photography of Jupiter’s upper atmosphere to see all the turbulent motion that takes place. A tranquil pond Jupiter isn’t.

Jupiter: Energy – Solar energy is highly unlikely to drive any Jovian biology because the atmosphere is very thick, and just like with our terrestrial oceans, things get very dark very quickly as one descends. However, chemical energy is a possibility, like that which drives terrestrial hydrothermal vent communities. Then there’s infrared (instead of visible) radiation. Jupiter radiates much more heat that it receives from the Sun, the heat being slowly radiated outward from Jupiter’s original quota of primordial heat energy largely stored in the core of the planet.  Jupiter is a fantastic place to visit if you’re fond of thunderstorms. Lightning really lights up the Jupiter’s skies. Lightning is a prime source of energy for driving chemical reactions. Translated, all up, Jupiter is awash with potentially useful energy sources to drive any local biology.

Saturn: CHON: The atmosphere of Saturn (which is what the mainly planet is – a ball of gas) consists of one hell of a lot of molecular hydrogen and some helium, a really skewed ratio relative to those elements found in the Sun, but that’s another story. However, it does explain why Saturn, if you could find a freshwater ‘pond’ large enough, would float in it! That aside, the atmosphere contains trace amounts of ammonia (there’s your nitrogen), acetylene, ethane and methane (and your carbon), plus phosphine - all have been detected. The upper atmosphere has clouds composed of ammonia crystals, while the lower atmospheric clouds appear to be composed of ammonium hydrosulfide and/or water (thus some oxygen).

Saturn: Environment: The same discussion that applies to Jupiter applies to Saturn, although because Saturn is a smaller planet (albeit massive relative to Earth) the habitable volume of Saturn’s quasi-liquid atmosphere will be somewhat less.

Saturn: Mixing: Saturn also has that hot interior, cold exterior dichotomy that exists in this gaseous/fluid planetary ball. It’s akin to the convection that occurs when you heat water on your stove. Hot water rises; cooler water descends. And while not as dramatic as time-lapse films of Jupiter’s atmosphere, it’s also obvious that Saturn’s visual ‘surface’ is anything but tranquil. In fact the winds on Saturn are among the highest of any planetary body in the solar system. However, being farther from the Sun, Saturn’s chemistry is not going to be quite as dramatic as closer-in Jupiter, and thus Saturn’s atmospheric ‘surface’ is a lot blander appearing.

Saturn: Energy – As is the case for Jupiter, and for much the same reason, solar energy (photosynthesis) is out on Saturn; chemical energy and infrared radiation (heat energy) will be the way to go. Saturn also radiates more heat that it receives from the Sun – two and a half times more in fact; Saturn is also a fantastic place to visit if you’re fond of thunderstorms. Lightning also lights up the skies of Saturn.

To be continued...

Exobiology: Life in the Outer Solar System: The Smaller Bodies

Exobiology was the original term given to the sciences central to the question of life-in-the-Universe. It’s now been largely replaced by Astrobiology, but I’ll stick with the original. To investigate life-in-the-Universe perhaps we should start a bit closer to home and look to our own outer solar system and some of the smaller abodes. Apart from Planet Earth, we have no absolute proof positive to date that any other life, albeit relatively simple forms compared to terrestrial life forms such as ourselves and associated companion animals and plants, exists within the confines of our solar system. However, the odds are fairly high, almost certain in fact; those other, extraterrestrial life forms do exist in our immediate cosmic neighbourhood. 

Europa (A Satellite of Jupiter): Europa is, apart from Mars, the current darling of the exobiology (astrobiology) set. There is evidence that Europa has a liquid water ocean underneath a thick ice cap that is kept from freezing solid by the flexing action imposed on the moon by its parent planet, Jupiter. If you have liquid water, an energy source, you therefore have possible life, or so goes the thinking.  I’m not quite as optimistic. The ice cap is thick enough so that any energy source available for life won’t be solar. The ocean will be in eternal darkness. That is however not a death blow as not all critters on Earth rely on solar energy. There could be hydrothermal vents, with associated living communities on Europa as there is on Earth. But, with the ice cap, there would be little in the way of resources added to the ocean from outside; that’s not the case on Earth. All chemicals that would sustain such life would have to be efficiently recycled. Life on Europa – possible, but it’s going to prove to be very difficult to explore that ocean, so I’m not expecting a definitive answer any time real soon.

However, there remains the possibility that materials contained within that hypothetical ocean may, due to tidal stresses, may be squeezed through cracks in the ice and find their way to rest on the surface. It’s therefore possible that a robotic craft that lands on the icy surface might detect organics and/or fossil or frozen solid microbes or even dead multicellular life forms resting on the surface.

[Note: To avoid unnecessary repeats, as a general rule of thumb, any satellite around Jupiter, Saturn, Uranus or Neptune that has a substantial part of it’s crust made up of ice, and is subject to extreme tidal heating by it’s parent planetary body (i.e. – you get a liquid ocean underneath a thin covering of ice), you have the potential for, as in the case of Europa, a habitable water-rich environment.]

Titan (A Satellite of Saturn): The satellite of Saturn, Titan, is one of the largest moons in the solar system, and in fact, if it existed all by its lonesome, could be considered a planet in its own right. Titan has, fairly unique among satellites, a dense atmosphere. It’s denser in fact than our own atmosphere. It also has the right sorts of chemicals that we identify as having a strong connection with organic and biochemistry. Were Titan the same distance from the Sun that Earth is, well, you could have a real twin of Earth, unlike our false twin, Venus.

Unfortunately, Titan is way, way, way – far away – from the solar energy source that makes Earth such a relative paradise. Thus, Titan is Earth, but an Earth in slow motion because Titan is so cold compared to Earth. If you think of Earth as liquid water at the equator, Titan is molasses at the poles!

Comets, Asteroids/Planetoids, Meteors: These relative tiny bodies can’t really qualify as habitable abodes to life, except, there’s evidence that not only can some of the above be rich in the sorts of chemicals associated with life (water, carbon compounds and organic chemistry), they could indeed be environments that could house dormant life forms or fossil life forms of a unicellular kind. Meteorites which have been gathered up and analysed on Earth (like ALH 84001) have yielded if not fossilised bacteria, then at least enough chemical evidence to suggest that they could have had a close connection with contributions towards an origin of life event.

Exobiology: Life in the Outer Solar System: The Gas Giants and Pluto

Exobiology was the original term given to the sciences central to the question of life-in-the-Universe. It’s now been largely replaced by Astrobiology, but I’ll stick with the original. To investigate life-in-the-Universe perhaps we should start a bit closer to home and look to our own outer solar system, starting with the gas giants (Jupiter, Saturn, Uranus and Neptune) and Pluto. Apart from Planet Earth, we have no absolute proof positive to date that any other life, albeit relatively simple forms compared to terrestrial life forms such as ourselves and associated companion animals and plants, exists within the confines of our solar system. However, the odds are fairly high, almost certain in fact; those other, extraterrestrial life forms do exist in our immediate cosmic neighbourhood. 

Taking each of the four gas giant abodes (the Jovian planets) in the outer solar system followed by Pluto in turn…

Jupiter (The Giant Planet): Jupiter is the largest planet in our solar system, but composed mainly of gas. In fact, Jupiter has been insulted by being compared to our Sun, but a failed Sun. If Jupiter had been a fair few masses larger, it would have ignited in a ball of thermonuclear fusion and become a second stellar object in our solar system, turning it into a binary star system. Jupiter however is still solar enough such that it emits more energy than it receives from the Sun. Jupiter, because of the intense gravity, compresses its own stuff, and compression produces heat. Important point number one: Jupiter has its own internal energy source.

Important points two, three and four: Secondly, Jupiter’s atmosphere is composed of the right sorts of chemicals that one identifies with origin of life events – hydrogen, methane, ammonia, water vapour, etc. Thirdly, Jupiter’s atmosphere is turbulent such that there is a lot of mixing of those elements and compounds. Fourthly, the atmospheric bands of Jupiter are highly coloured, an indication that there’s lots of complex chemistry including organic chemistry going on within.   

The upshot of all of this is that it is not implausible that within the upper reaches of Jupiter’s atmosphere, as per the case of Venus, simple life forms couldn’t exist, survive and thrive. You have the chemistry – you have the energy. And maybe Carl Sagan was right and that something more complex than just a unicellular ecosystem could exist in Jupiter’s atmosphere. But it would have to be an atmospheric ecology.

Saturn (The Ringed Planet): Saturn is a quasi twin of Jupiter. Although slightly smaller and farther away from the Sun than Jupiter, the same general arguments that apply to Jupiter apply to Saturn. That is to say, Saturn has the right sorts of chemistry – and an internal energy supply. It’s however slightly less dense than the other gas giants, such that if you could find an ocean big enough, Saturn would float! That however has no bearing on the issue of finding an atmosphere-based ecosystem there.

Uranus: Uranus is a poor cousin compared to the likes of Jupiter and Saturn. It’s mainly a gas planet, albeit way smaller, but so far out from where it’s all happening that it isn’t too likely that even simple life could flourish in the atmospheric depths, although the chemistry isn’t dissimilar to that of the closer-in Jovian planets of Jupiter and Saturn.

Neptune: The same sorts of arguments apply in general to Neptune as to Uranus, with one slight exception. Although farther out, Neptune, like Jupiter and Saturn, radiates out excess energy. It’s solar independent, at least as far as any life forms might describe their environment and energy supply.

Pluto: The planetoid Pluto was recently officially demoted from strict planetary status, and is no longer acceptable to refer to it as the ninth planet. However, when I was growing up, it was the ninth planet, and so I say buggers to astronomical officialdom. That rant aside, Pluto is hardly top rock for vacation seekers. It’s cold. I mean it’s really cold. It makes Antarctica seem absolutely tropical in comparison. I mean polar bears would freeze to death on Pluto, not that there’s anything reasonably resembling an atmosphere as we know it for them to breathe. Again, Pluto is too cold to allow for the high temperature chemistry we associate with life-as-we-know-it. If you’re looking for life in our solar system, Pluto wouldn’t be your first port of call.