Cosmic Driftwood

  Long long ago, earth, the moon, the planets and even the sun were all just dust, clumping together from a huge cloud of primeval gas and dust called a molecular cloud. This cloud contained all the materials needed to produce the sun and planets, but a little bit was left over: primeval fragments of the new solar system. Some of these fragments became asteroids, and dwarf planets.Others became comets: wandering pieces of ancient rock and ice, moving through the solar system. A well known example of a comet is 67p, visited recently and studied up close by the Rosetta Mission and Philae Lander.
  Now, comets are special. 67p was found to harbour some very special compounds; molecules called precursor compounds. In this case the molecules were organic -or carbon containing- some were precursors to important organic molecules such as amino acids and DNA.
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Comet 67P /Churyumov-Gerasimenko, or just plain 67P to it’s friends. A true rock star of the comet world.
  In earth’s earliest days the planet was thought to be something like Hell. It was no place for life, and yet here we are. All of us! Somehow, life on earth took off. Some researchers believe raw materials for life may have been delivered to earth by comets; sprinkled far and wide like a chef going nuts with the salt and pepper.
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Great views, lousy air. Sauron would have loved it.
  Now, as far as we know, earth is the only planet in the entire universe known to definitely harbour life. I’ve spoken briefly about some of the conditions for life in other episodes.  Check out these links.
  But there are a lot of other worlds out there, both in our solar system and beyond, and there’s a lot of stuff floating around in space. We owe our existence to such a collection of stuff, coagulating and sticking together to form the Sun and planets.
Europa is the fourth largest moon of Jupiter. It’s a little smaller than earth’s moon, and the fifteenth largest object in the solar system:
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A comparison of the Earth/Moon system and Europa. Beautiful, aren’t they?
  Why am I suddenly talking about Europa? Because astrobiologists (people who examine the possibility of life on other planets) believe that Europa may harbour it. It’s believed to possess an ocean 100 kilometres deep, beneath an icy shell several km thick. This ocean is believed to be salty- like our own. This is important, because the minerals and chemicals dissolved in seawater form an important backbone of deep sea ecosystems concentrated around hydrothermal vents. On earth these vents are practically bursting with life. These vents on earth are geothermally heated, relying on heat from deep within the earth. Ecosystems in this Europan ocean may be heated by Jupiter. This is because the gas giant’s gravity tidally massages the moon, creating heat from frictional forces within the moon.
Just imagine what probes to Europa will find when they eventually take a peek beneath that ice! What I wouldn’t give to see it…
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Some conventional views on the structure of Europa. 
  It’s at least possible that around 3.8 billion years ago earth was seasoned with some of the ingredients for life by cosmic passersby. But could it have happened in reverse?
Could this have happened elsewhere in the solar system?.
Life on earth, by and large, is simplistic in structure and function. It has spread to almost literally every corner of our blue-green marble, and it continues to pop up in strange places. Some of them are far too hostile for humans or more complex life forms to survive in. One of the main mechanisms this simple life has used to conquer the globe is simple dispersal. This could be a sneeze distributing countless thousands (millions?) of freshly minted cold viruses far and wide. It could be a gentle breeze, scattering thousands of fungal spores across a forest floor. Many simple organisms spread themselves far and wide by hitching a ride on other organisms. Countless examples exist in nature of organisms that use others to do the work for them. Plants create seeds that are ingested by animals and spread in droppings. Bees not only distribute pollen, they also often carry other organisms: fungi etc, to new locations. Cats and corn are examples of organisms which have conquered the planet alongside humanity, by making themselves favourable.
  Most of these mechanisms have developed over time, becoming “the done thing”. But other times throughout the history of life, species have been flung far and wide by accident.
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Plants have successfully colonised every continent on Earth via dispersal mechanisms such as this driftwood.
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Oh dear. The dog was rescued.
Could Earth seed other planets with life? Imagine if places like Europa have already been seeded with life; not by comets or rogue asteroids, but by Earth. I would like to devote a series of posts to this topic, on mechanisms whereby by organisms from earth could reach other worlds without human intervention.
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Have we beaten ourselves to other planets?

Sometimes, science and a love for science begins with a story or two. I’ve always loved stories, be they in the form of books and movies. My favourite books of all time were C.S.Lewis’ Narnia Chronicles and Micheal Ende’s “The Neverending Story”.

What drew me into these particular stories so deeply was their references to cosmologies; to other realms and universes. For me the most alluring stories create not just intrigues and conflicts. I don’t really care about The Hero’s Journey, complete with it’s checklist of stages in a story. I don’t really care who’s the protagonist or antagonist. I care about the world these tales take place in. When I’m immersed in a story, I want to be  immersed in the story. A universe, with all it’s history,  is a key element of imagined worlds. To borrow a line from “The Dark Tower” by Stephen King:

Beyond the reach of human range,

a drop of hell, a touch of strange. “

Again this tale was heavy with cosmology; alien yet familiar.

These stories were life changing for me in ways. They each provided pieces of a picture, of a universe I’d come to explore. The Narnia books were about other dimensions. “The Magician’s Nephew” featured travel between alternate realities. “The Neverending Story” showed us a universe created by imagination and perception. “The Dark Tower” was about a post apocalyptic world where the laws of space and time were unravelling, where the natural order of things was succumbing to a slow heat death.

But what about our own personal stories?

When I was a kid I spent a lot of time inside my head, visiting other worlds and other times. It was easy to imagine a beach as a coastline on some alien planet, or national park as some dinosaur infested part of Earth’s distant past.

Good times.

The point I’m getting to here is that imagination and stories are important for science because they show us other worlds we’d like to explore.

But what about our own worlds and stories? As I’ve mentioned I spent a lot of my childhood immersed in imagination. If I couldn’t find someone else’s world….I’d provide my own.

I harp on about these other worlds, because the ability to imagine leads to the ability to ask questions. It enables you to speculate. It enables you to perform thought experiments..

Imagined scenario:

An international mission to the outer solar system; the culmination of countless thousands of hours of diplomacy, frustration and determination finally reaches it’s goal.

A lone robotic probe has inserted itself into orbit over Europa. This moon has had the hearts of astrobiologists beating faster for a long time now. They’ve been curious about a global ocean ten times deeper than our own, lying beneath a cracked ghostly shell of ice. Oh yes, Europa could be the culmination of so many dreams..

The probe has been asleep on it’s long journey, stirring occasionally in the deep night to whisper to it’s masters. Digital murmours head home across a solar system filled with shrieks and moans: electromagnetic noise emitted by the planets themselves.

Who knows what the planets are saying?

The probe doesn’t care. It’s staring down at it’s new home. It fusses and frets, seperating and sending a lander down.

Vast sheets of rusty ice buckle and shift. The slumbering moon rolls in its sleep and a geyser of salty water erupts, pelting the lander with ocean spray as it prepares to land. Sensors coating  the probe’s metallic hide taste the spray, sampling the alien cocktail for signs of life….

The moon is permanently encrusted in a shell of ice several kilometres thick. Below lies a deep salty ocean, warmed by constant tidal squeezing from Jupiter. This causes friction and tectonic stresses that render this moon a place of interest.

The probe takes a look around. The sky is eternally dark, and Europa is beholden to mighty Jupiter, which rolls and boils slowly across the night. Excited chatter from home has the probe going straight to work. Sophisticated AI takes over. Arms and legs extend and the probe stands. The days of ugly little rovers belong to antiquity now. Now a tall humanoid drone stumbles across endless Europan permafrost. Shattered ridges of glacial ice reach into the frozen sky like broken continental plates.

The drone walks. The drone sees. It picks up handfuls of snow. Sensors and chemical testing labs are woven throughout it’s frame; the very best nanotech taxpayer and corporate money can buy. The drone tastes the snow with it’s hands, looking for life. It’s masters believe it to be here.

Powder gently falls from the sky, leaving pock marks in the dark snow. There are organic molecules and precursors to life here. The drone tastes them. It looks for openings in the moons icy shell. If it can find a fissure it will climb down, until it reaches the watery underworld. Then, it  will swim, exploring a place that up until now has only been a dream.

Then, it finds something unexpected.

A metallic gleam in loose shards of icy ejecta catch the drone’s eye…

The drone bends down and tastes tarnished copper. What is this?

The drone is not prepared for this.

It is programmed for the chaos of the real world: a state of the art descendant of  the old survey/search and rescue bots. Protocol kicks in, and the drone dutifully sends images to it’s masters…

The machine is patient-as is it’s wont. It continues to explore the ice canyons and expanses of rusted ice. Life is here. The drone’s masters believe this fervently. Onboard mettalurgical analysis by the drone is now being carefully studied back home.

Back home the drone is all but forgotten. All attention is on the artifact it has found. Dutifully the drone sends back reams of data. Most of it is of incredible scientific value, but outside Mission Control no one is really noticing.

Instead, the world’s eyes are on a piece of the ancient world. Rome, to be exact. A speartip, broken away from it’s wooden haft, and buried in alien ice, 628 million kilometres from the Eternal City.

How did it get there?