A sci-fi short story first written in December 2015.
Lucy opened the fridge and pulled out the dark brown bottle, shaking it gently to hear the capsules inside rattle. She unscrewed the lid, tipped up the bottle and emptied a couple onto her palm. Rod-like capsules, pale brown in colour. They looked ordinary, benign – like any other run-of-the-mill probiotics you could buy. But Lucy knew these weren’t ordinary. Each capsule contained billions of bacteria, a strain she had developed. Lucy felt a stirring of butterflies in her stomach; this feat of genetic engineering was tremendous.
It was only a few decades ago that scientists had begun to realise the profound impact of microbes on humans. The first clues came with the observed correlation of mental illnesses and obesity with gut microbiota. Then scientists found “the second brain” – 100 million neurons lining the human gut, forming the enteric nervous system, connected to our brain via the vagus nerve. But this wasn’t a one-way connection. Biochemical signals from the gut and its bacterial inhabitants were affecting the brain.
Research into the human microbiome boomed. From influencing our physical and mental health, to our behavior and personality, our bacteria seemed to be an omnipresent, insidious force that had crept into every facet of our being. With symbiotic microbial cells outnumbering human cells ten to one, scientists began to ask questions about how “human” we actually were. The answer: no longer was a human a single organism. We were walking, talking ecosystems, each of us home to a population of single-celled species as unique as our fingerprint.
Lucy was captivated by this idea. She had grown up during an exciting period of scientific advancement, and wasn’t constrained by outdated concepts of humans as autonomous individuals. In Lucy’s mind, the ability to alter your microbiome offered limitless possibilities. Why perform complex neurosurgery when you could produce the same effect via the gut? The concept was straightforward enough in theory: with detailed knowledge of the biochemical pathways in the brain, you could genetically engineer bacteria to produce a specific cocktail of neurotransmitters. By administering these bacteria with an oral probiotic, you could influence the biochemistry of the brain. She dreamt of boosting memory and enhancing intelligence.
But she no longer had to imagine. With this simple pill Lucy held in her hand, it would be a reality. Lucy had tested her treatment in mice with promising results. Her latest experiment involved tracking the neurotransmitters in real-time as they travelled from the gut to the brain. She used protein biomarkers which fluoresced green, blue and red when they bound to the tiny but powerful neurotransmitters. Lucy felt a warm glow of pride radiate from her abdomen the first time she saw the colourful fluorescence illuminate. Her very first human trials were just around the corner. If successful, the consequences for mankind would be spectacular – it would usher in a new era of creativity and progress in science.
Lucy snapped out of her daydream. She returned the probiotics to the fridge and entered a glass-enclosed corner of the lab. A warm yeasty smell permeated the air – bacterial broth freshly mixed. She spent long hours in the lab and she liked it best at night when the lab was quiet, so she could think. She felt less pressure without the suspicious eyes of her labmates examining her every move. Sometimes she noticed them reading her lab book, or examining her experimental set-up closely. It made her uncomfortable, so she tried to avoid the busy times of day. Lucy felt an affinity for her bacteria and she raised them with great care. She watched the tall conical flasks swirling in the incubator. The shaking platform inside the glass case whirred and the brown liquid inside the flasks sloshed to and fro.
Behind Lucy, the glass door slid slowly open. A gentle whooshing as a draught entered alerted Lucy and she froze. Who else would be working this late?
It was Martin, the lab leader. Lucy turned slowly to face him. Martin was short and stocky, with horn-rimmed glasses and a cardigan slung over his shoulders. She didn’t particularly like Martin, who had an air of superiority and an egotism that didn’t sit well with her. He spent most of the day in his office talking loudly and guffawing with the other “old boys” who still occupied the upper echelons in chemistry. Progress for women in Lucy’s field had come more slowly than others. Nonetheless, Lucy tolerated Martin because his lab was well-stocked and he gave her a great deal of freedom in her research.
Lucy noticed the bottle of acid in Martin’s hand and she felt her stomach butterflies flicker – an unpleasant, foreboding flickering.
“I’ve been following your progress Lucy, and I have to say, I’m very impressed. You’ve got further than I expected with this project.”
“You’re quite welcome. But I have some bad news Lucy. I’m afraid I can’t allow you to continue with this avenue of inquiry any further.”
Lucy frowned, taken aback. “But why? I’m so close. I don’t understand.”
“You see Lucy, you’ve gotten a little too far for my liking. Your intentions for this technology don’t really, ah, gel with my vision.”
Lucy stared, speechless. Her intentions had been nothing but noble.
Martin continued, “I like the premise. An oral probiotic to alter the mind. So simple and elegant. Brilliant, even. “
Martin flung the open bottle of acid at Lucy’s face and she recoiled in excruciating pain as it burned her face and chest. She collapsed, writhing on the floor. Martin turned to the conical flasks whirling madly in the incubator. His lips contorted into a smirk.
A few mornings later, Martin sat in his office and opened the local newspaper. In the corner of page five was a brief article.
“Scientist injured in lab accident.
Dr Lucy Johnston, scientist with Labrax Pharmaceuticals, was in an accident last week while working late at the Labrax Laboratory. A chemical spill, involving highly corrosive hydrochloric acid, occurred at about 11pm. Dr Johnston’s colleague, Professor Martin Bourke, was in a nearby office at the time and was able to call for medical assistance. ‘This is a terrible accident and all of us here at Labrax wish Dr Johnston a speedy recovery. The company will be doing everything possible to assist Dr Johnston, including taking care of her medical expenses,’ said Professor Bourke. Dr Johnston is said to be in a stable but serious condition at a private hospital. The Health and Safety department of Labrax Pharmaceuticals is investigating the incident.”
Lucy awoke in a daze. Her face was covered in bandages, save for a slit for her eyes. From her restricted view, she could see a hospital room – all white, sterile with glaring fluorescent light. She tried to move her arms and legs but they were restrained. Her mind felt fuzzy, black and white static.
Crisp footsteps signaled the approach of someone, but she couldn’t see. A hand gently moved the bandages near her mouth, and pressed a rod-like capsule between her lips. She swallowed.
Martin entered the room and addressed the white-coat-clad person tending to Lucy, “How’s our subject coming along?”
“Excellent. She really had done a fantastic job – just a few tweaks to genes here and there and we’re fairly certain we’ve got a product capable of altering thoughts. The trials this week will confirm we have established control.”
Martin felt an anticipatory fluttering in his stomach. Why settle for advertisements and pop culture to influence psychology, when you could so easily get right at the brain itself? He imagined controlling vast populations using mere suggestion. The consequences for the elite of mankind would be spectacular. It would usher in a new era of power and wealth. Soon, he’d no longer have to imagine.
First written in November 2015.
“Only spread a fern-frond over a man’s head and worldly cares are cast out, and freedom and beauty and peace come in.”
– John Muir
One of my favourite things about walking in the bush is the thick carpet of ferns that often adorns the forest floor. Lush and green with a mesmerising symmetry – they add a certain aesthetic, a richness and depth to the layers of forest. As a celebration of this humble beauty, here are some recent fernlicious snaps.
I’ve been trying to learn more about New Zealand’s fabulous native flora – how to identify species, what they’re used for by Māori traditionally and in modern times, and what role they play in our forest ecosystem. There’s a lot to learn – NZ has about 200 fern species, and around 40% of them are found nowhere else in the world! This is unusual for a temperate country, as our ferny friends are typically found in tropical areas. New Zealand’s fern species range from towering mamaku, up to 20m high, down to delicate fronds only 20mm long.
Ferns are not just pretty either – they’re tasty too! Young fern fronds of two species, hen & chicken fern (Asplenium bulbiferum) and the common shield fern (Polystichum richardii), are eaten by Māori as a vegetable. The edible undeveloped fronds are referred to as pikopiko, and can be served as a relish (kinaki) for potato. Visit the Māori Plant Use database to learn more.
The silver fern, or ponga, is a national symbol of New Zealand – while the fronds of this tree fern are green on top, their underside is a beautiful silvery grey.
Sometimes, it’s the little wonders that set your heart alight.
First written in October 2015.
Have you voted yet? Every year, Forest & Bird runs the New Zealand Bird of the Year comp. The aim is to raise awareness of the amazing avian species we have here in NZ, and to promote their conservation.
So who will you vote for? Here are some fully rad options for you:
KEA (Nestor notabilis)
This “clown of the mountains” is the world’s only alpine parrot. Fave pastimes include eating cars, locking hikers in back country huts and being general cheeky bastards. These guys are very intelligent – they can solve logic puzzles and have been recorded using tools. Kea were once hunted for bounty due to their badass destructive antics, but they now have full protection. Sadly, they’ve become endangered. Visit the Kea Conservation Trust for more info, or like them on Facebook.
KĀKĀPŌ (Strigops habroptilus)
A chubby, flightless and nocturnal parrot, there are only 125 kākāpō in existence. You may have heard of kākāpō thanks to Sirocco, who notoriously shagged Mark Carwardine on “Stephen Fry’s Last Chance to See” (see below). Male kākāpō BOOM to attract mates, and they are the heaviest and longest-living parrots. In 2013, they were (quite unfairly, I must say) voted the second ugliest animal. How could you call this adorable face ugly?! Visit Kākāpō Recovery on their website or Facebook to learn more. You can also read more about kākāpō here.
KĀKĀ (Nestor meridionalis)
Forest-dwelling relative of the kea, these fellas are also well-known for their cheekiness. Most kākā are grey-green, but some have a gorgeous red colour variation. Kākā are basically the closest thing to dinosaurs, retaining some ancient parrot characteristics since they split off from their cousins around 100 million years ago. The kākā is at risk due to habitat loss and predation from introduced pests, but has recently been welcomed into the leafy subrubs of Wellington. Zealandia Ecosanctuary is backing this bird: YES WE KĀKĀ CAN!
BAR-TAILED GODWIT (Limosa lapponica baueri, kūaka)
This insane mofo completes the longest non-stop flight of any bird, migrating between the Arctic tundra and temperate regions in Asia/Australia/New Zealand. It’s been recorded as flying more than 11,000km over 9 days, the longest trip without stopping to feed of ANY animal. Like woah, THAT’S CRAZY DUDES. When they’re not flying ridic long distances, they can be found chilling in mudflats and marshes, munching on insects, crustaceans and aquatic plants. Tasty.
CHATHAM ISLAND BLACK ROBIN (Petroica traversi)
This lil black sphere is super resilient, battling back from the brink of extinction, fo’ real. There are now around 250 black robins, but back in 1980, there were only five left. ONLY FIVE. This included a *single* fertile female, named Old Blue. Using cross-fostering techniques, Don Merton and his Wildlife Service team were able to save these cuties. As all individuals are descended from Old Blue, there is unfortunately little genetic variation between them. Interestingly, this doesn’t seem to have caused any inbreeding issues, suggesting that the species has suffered similar population bottlenecks in the past. Ain’t nature crazy cool?
FIORDLAND CRESTED PENGUIN (Eudyptes pachyrhynchus, tawaki)
These dapper chaps have excellent eyebrows. Just look at those spiky yellow plumes! You won’t find these rare penguins in the Antarctic – they live in colonies in coastal temperate rainforest. Tawaki mate for life, and like other penguins, they don’t have teeth. Instead, they have nightmare-inducing fleshy spines that allow them to swallow their food whole.
KĀREAREA (Falco novaeseelandiae, New Zealand Falcon)
Don’t get on this dude’s bad side – despite their small stature, these birds of prey are fiercely territorial and will attack people. Unlike their larger swamp harrier relatives, kārearea won’t be found scavenging carrion. Instead, they prefer to display amazing aerial acrobatic prowess and snatch their prey out of the air, or grab them off the ground with their sharp talons. These falcons are speed demons, reaching speeds of up to 200 km/h. And they’re not just fast – they’re gutsy too, killing prey UP TO SIX TIMES LARGER than itself. WOAH. If you’re a fan of a classic Marlborough sav, vote kārearea! They have been introduced to the Marlborough wine region to deal with grape-devouring pests. Check out Wingspan Birds of Prey Trust.
KERERŪ (Hemiphaga novaeseelandiae, New Zealand Pigeon, Wood Pigeon, kūkupa, kūkū)
With a white singlet stretched over their rotund middle and whooshing wings in flight, it’s hard to miss these tubsters in the bush. These guys are trendsetters, living the raw vegan lifestyle way before it was cool on Instagram – they mainly eat fruit, with a few flowerbuds thrown in. Kererū are super important to many native plant species, including kawaka and tara, dispersing their seeds via poop. If the kererū disappeared, our beautiful lush NZ forests would never be the same again. The kererū was an important food source for Māori, however it is now illegal to hunt them. Other threats to these forest fatties include predation by rats, stoats, cats and possums. Go to Kererū Discovery and Project Kererū to learn more.
KŌKAKO (Callaeas wilsoni)
These intriguing North Island forest-dwellers have grey plumage, a black eyemask and striking blue wattles. They once had a South Island cousin adorned with orangey wattles, who is sadly now presumed extinct. Like many NZ birds, this fella has a hard time flying and instead prefers to hop around, scramble up trees and glide – more like a flying squirrel than a bird! This behaviour evolved in the absence of mammalian predators, so the introduction of nasties like stoats has had a devastating effect on our kōkako friends. They have a clear, bell-like call which can be heard ringing across the forest for kilometres in a “bush choir.” Visit Hunua Kōkako Recovery Project to see more of these woodland warblers.
TAKAHĒ (Porphyrio hochstetteri)
The largest member of the rail family, this stocky big-beaked bird was once presumed to be extinct. Incredibly, a small population was rediscovered in 1948, deep in the rugged mountains of Fiordland National Park. The takahē once inhabited swamps, however conversion of swampland to farmland left them searching for a new home. They found it higher up on the tussocked mountainsides, where they dine on alpine grasses. The takahē is flightless, and is at risk due to predation by stoats and competition for food sources with deer. There are currently around 260 takahē, with several populations residing on predator-free island sanctuaries.
WRYBILL (Anarhynchus frontalis, ngutuparore)
This plump lil plover is endemic to New Zealand. The wrybill is the only bird species to have a sideways-bent beak. Why, you may ask? To reach under and around riverstones to catch some delish insect tucker, of course. WOAH EVOLUTION YOU CRAZY. The wrybill breeds in the braided rivers of the South Island, and spends January to July each year holidaying in the estuaries of the North Island.
Of course, there are many other fabulous birds you can vote for; this is just a small selection of the feathered phenoms we have here in lil ol’ Aotearoa. VOTE HERE then let me know who you voted for & why in the comments!
First written in March 2015.
New Zealand is well-known for our array of birds-that-are-more-like-mammals (thanks, evolution!). We have long been recognised for our namesake bird, the kiwi, but the roly-poly kākāpō is rising through the ranks of “world famous in NZ” stars. I’d contend the kākāpo is the fourth most popular folk-bird in NZ, seeing as they’re pretty much the avian version of the Flight of the Conchords: awkward but endearing and oh-so-funny. If you haven’t heard of these delightful but eccentric parrots, I can guarantee your life will be all the richer once you get to know them!
The kākāpo is a rotund parrot with an owlish face and exquisite green mottled feathers. This soft, dappled green is excellent for blending into the lush NZ bush, which is handy for kākāpo who seem opt for “freeze” rather than “fight or flight” when taken by surprise. Kākāpo take the title for “world’s heaviest parrot” so it is no wonder they also take the honour for “world’s only flightless parrot.” These adaptations served them well in pre-human NZ, as they were able to effectively avoid predation by the giant but now extinct Haast’s Eagle that ruled the daylight skies. They may not be able to soar majestically, but kākāpo are great at “controlled falls” out of trees, with the grace and elegance of a flying brick. Despite their limited flight abilities, kākāpo are fantastic climbers and one has even been known to evade capture by Department of Conservation rangers by scaling a rimu tree tens of metres tall. Cheeky as!
Kākāpo are largely solitary birds, leaving their home range only to breed. Like many of their other characteristics, the kākāpo’s courtship is rather unusual. Kākāpo are considered “lek” breeders, which means that the males compete with each other to attract the attention of females. The male kākāpo’s “stall” in this “marketplace of seduction” consists of a shallow bowl dug into the ground, cleared of any forest debris, with a couple of tracks leading to it. This “track and bowl”, typically located high up on a hilltop, is the stage for a remarkable performance. Forget milkshakes ‘cause they don’t bring the kākāpo to the yard – these birds are are all about that bass. The male will puff himself up into a fat feathery ball and commence “booming.”
His boom is amplified by the bowl and reverberates across the valleys, attracting females from far and wide. Sometimes he will alternate his bassy booms with a “ching” call that allows females to hone in on his location. Gotta get dat boom-boom-ching!
What happens next? This video featuring Spokesbird for Conservation Sirocco Kākāpo may give you an idea…
The female will then typically lay one to four eggs, that will hatch after 30 days. You can see a kākāpo hatchling in this video (they aren’t the most attractive baby birds, hey).
This bizarre breeding display only occurs once every couple of years – only when there’s sufficient rimu fruit around. Ordinarily for kākāpo, this slow pace would be all good, as they can live for 90 years, and maybe even 120 years. However, human settlement, habitat destruction and introduced pests such as stoats and cats have led to a significant decline in kākāpo numbers. Fossil records indicate that the kākāpo were once widespread throughout NZ and were our third most common bird, but today, they are considered critically endangered.
Conservation efforts began as early as the 1890s, with conservationist Richard Henry transporting 200 kākāpo in his dinghy from Fiordland to Resolution Island in an attempt to save them. Sadly, stoats soon swum to Resolution Island and wiped out Richard Henry’s endeavours within just six years. Today, only 126 kākāpo remain, and each is individually named – a stark reminder of the species’ precarious situation. These survivors live on offshore, predator-free islands, with about half calling Whenua Hou (Codfish Island) home.
The good folk at the Kākāpo Recovery programme intensely manage the kākāpo population and have overseen an increase in their population from just 86 individuals in 2005. Each bird is fitted with a radio transmitter and supplementary food is provided to encourage successful breeding. The kākāpo are trained to use their food hoppers with “Hansel & Gretel” style trails of kumara. Some hoppers are even fitted with devices able to identify specific kākāpo via their radio transmitter – this prevents naughty kākāpo from raiding their neighbours’ tucker!
One particularly mischievous kākāpo is Sirocco, who I have already mentioned is the Spokesbird for Conservation and star of “Last Chance to See” with Stephen Fry. Sirocco had a rocky start to life, suffering from a respiratory illness at three weeks old. In order to improve his chances of survival, Sirocco was handraised and returned to the wild once he was healthy, after a few months in human care. However this stint in the company of humans had a lasting effect, as it soon became clear Sirocco believed he was Homo sapiens and not Strigops habroptilus. Sirocco was so enamoured with his human saviours that he built his “track and bowl” on the path between the ranger hut and toilet on Codfish Island, and attempted to mate with any unsuspecting volunteer or ranger who ventured out for a midnight pee. Due to his imprinting on humans, Sirocco was deemed unsuitable for breeding but he had a natural affinity for the limelight. He spends most of his time living peacefully in the wild, but does “go on tour” like any rockstar, visiting various locations around NZ.
Kākāpo are intelligent, curious and have distinct personalities – they are an extraordinary species, precious taonga (treasure), that we cannot afford to lose. With charismatic advocates like Sirocco, a well-funded breeding programme and the procurement of predator-free habitat, there is hope for our fascinating feathered friends.
This post was inspired by a recent talk given at Forest & Bird.
You can visit Sirocco Kākāpo on Facebook here.
First written in February 2015.
Forget counting sheep, tallying our feathered friends is a surefire way to get to sleep – not because it’s boring, but rather exhausting.
Recently, I ventured out across the Canterbury Plains to Te Waihora (Lake Ellesmere) to participate in a planning day for the Te Waihora Trust’s annual bird count. Despite its proximity to Christchurch, I had never visited this vast, 5000-year-old lagoon, whose Māori name means “spreading waters.” The lake has a fascinating history, both ecologically and culturally. It was formerly the mouth of the Waimakariri river and as our accompanying ranger explained, “The Waimak is like an out-of-control water hose. It’s only due to human intervention that it’s stayed put.” To the local Maori people, Ngai Tahu, the lake has long held significance as a mahinga kai (important site for food and other natural resources). For hundreds of years, they cleverly maintained the lake at an optimal level for the birdlife, an important food source, while eels and fish were abundant. Sadly, post-Pakeha settlement activities such as farming and commercial fishing have degraded the lake and the life it supported.
Nonetheless, Te Waihora remains an important bird habitat, with as many as 98,000 birds present at any one time, and more than 150 species recorded. Its natural beauty is of the sweeping, sparse variety. Emerging from the surrounds of farm fields onto the vast Greenpark Sands reveals an extraordinary expanse of brown, red and dull green beneath a bowed grey sky. The ground is cracked and dry – a symptom of the ongoing drought in Canterbury.
Just a few days ago, a flock of around 600 banded dotterels were here, but today we can only find a few flocks of about ten, camouflaged in the glasswort and salt grass. The lake is the fifth largest in New Zealand, so there is lots of area for the birds to cover. My binoculars are heavy and difficult to keep steady, and with the birds constantly moving, it requires good concentration to count them. Just imagine counting hundreds, or thousands! We near the lake edge, which appears shimmering grey in the heat haze (even though it’s quite chilly). There are black swans, wrybills and pied stilts spied from binoculars. A tern soars overhead. The avid birders are excited to spot a lone red-necked stint amongst some dotterels, a species that migrates between the Arctic and Australasia. A couple of hours have passed as we have wound across the saltmarsh, stopping intermittently to watch and practice counting. It’s tiring work. I’m just an amateur keen to see beautiful birds and be outdoors, but some “twitchers” take their birds very, very seriously.
I couldn’t make the actual count itself – but an impressive 48,000 birds were counted. You can visit the Waihora Ellesmere trust on Facebook to see pictures of the count.
First written in October 2013. Guest blogger Lachy joins me to explore the fascinating world of fish. We wrote this piece for a science communication class.
Fish are friends, right? Yes they are. But unlike our human friends, we don’t know some basic things about them. So in order to get to know our aquatic acquaintances better, here’s three things we’ve wondered about recently.
1. Do fish vomit?
Inspired by this incredible Youtube video of cats puking to a techno soundtrack, we wondered, do fish vomit? With his usual “I know everything guys” approach, Lachy immediately claimed that vomiting is a function all vertebrates must have. Ellen, being skeptical of such a presumptuous claim, used her impressive googling skills to uncover the truth behind this piscine puzzle.
Living on Earth has its upsides. Literally. We (almost always) know which way is up or down. But in space, up or down doesn’t even exist! This can make life hard for creatures when they get sent to space by meddling astronauts. Lachy has seen a Youtube video of pigeons in zero gravity, and they really struggled. So what about fish in space? Would Dory be able to “just keep swimming?”
Hypothetically it could be very hard for fish. They stay upright in our oceans because of buoyancy: the force of gravity acts more strongly on the water around them than on themselves. So in space, they might just float around randomly, unable to control their movements or swim at all!
In 1973, this mystery was investigated in the Skylab. Two “mummichog” specimens were observed to dive incessantly, resulting in circular motions “as if stuck to the hands of a clock.” This phenomenon is called “looping.” But after a few days, the mummichogs stopped such weird locomotion and began to swim normally, with their backs oriented towards the cabin’s light source.
3. Do fish feel pain?
If you’ve ever gone fishing, you’ve probably seen fish writhing as they are reeled from their watery homes, hook embedded in their mouth. Are these poor creatures in pain? Battles have raged in both the scientific literature and public court of opinion over whether fish can feel pain. But the most recent study, conducted by an interdisciplinary team of neurobiologists, fishery scientists and behavioural ecologists, concluded that fish do not feel pain the same way humans do.
Studies claiming fish can feel pain have relied on interpreting fish behaviour. But fish lack the part of the brain that perceives pain in humans, and administering painkillers, such as morphine, produces no effect on them. This suggests fish can’t feel pain, but either way it doesn’t make sense to decipher the meaning of fishy behaviour from a human perspective.
First written in April 2013.
In another triumph for NASA’s Kepler mission, two new planetary systems have been discovered. While such a discovery is not really a rare event anymore – 137 new exoplanets were found last year – a couple of factors make this finding particularly noteworthy.
First of all, some of the planets are “Super-Earths” – that is, they’re not too much bigger than our home planet. One of them, Kepler 62f, has a radius only 40% larger than that of Earth. What’s more, it is postulated to have a rocky composition.
Secondly, three of the planets are located in the so-called “habitable zone.” This is the region surrounding a star in which a planet could theoretically have liquid water on its surface. One of the planets, Kepler 62f, is the closest in size to Earth ever discovered in a habitable zone. Another, Kepler 69c, orbits a star that belongs to the same classification of our sun (G-type). Kepler scientists claim this is “a significant milestone toward finding truly Earth-like planets.”
While Earth-like planets seem like a logical starting point for our quest to find extra-terrestrial life, restricting our search to such a narrow range of environments may in fact be unnecessarily limiting.
There are many other factors to consider when it comes to deciding whether liquid water can exist on a given planet – from atmosphere, to stellar radiation, the age and type of the host star and of course an origin for water. Conversely, it is possible that environments conducive to life as we know it exist outside habitable zones – in fact, there is one such potential environment in our own solar system. Jupiter’s moon Europa is hypothesized to harbor a subsurface ocean similar to the deep oceans of Earth. The likelihood of this was bolstered recently with the discovery of an “unidentified and unclassified” bacterium in a lake buried under kilometres of ice in Antarctica, an environment postulated to be similar to that of Europa. Effects ranging from volcanic activity to planetary mass can facilitate conditions beneficial to life, and it is also possible that life may originate on a planet that starts in the habitable zone, but then ends up outside it.
The existence of extremophiles on Earth suggests life can arise in a diverse range of conditions – on Earth it can exist in volcanic vents and nuclear waste! The resilience of life is epitomized by tardigrades and bdelloid rotifers, peculiar organisms which are extremely resitant to harmful radiation and extreme temperatures. Tardigrades have even been shown to survive in the vacuum of outer space. A couple of other factors suggest that life may be more resilient than we expect: organic molecules are able to exist in the interstellar medium, despite the inhospitable radiation. Additionally, geological evidence suggests that life appeared early in Earth’s history – perhaps as early as 3.85 billion years ago. Earth back then wasn’t like Earth today: it was hot, with a toxic atmosphere of carbon dioxide, ammonia and other gases, and a multitude of volcanoes. Despite this seemingly uninhabitable environment, life managed to emerge.
The border between living and non-living is blurred, and exactly what constitutes a living being is a contentious issue. Biology has traditionally characterised life as matter that is able to metabolise, grow, respire and reproduce – but this definition is arbitrary and also problematic, as it leaves entities such as viruses in a grey area. Viruses possess genes, utilise natural selection and reproduce via self assembly, however they lack cellular structure, metabolism and cannot reproduce independently. These perceived shortcomings preclude them from the ranks of living things. Our definition of life has been inconstant, and has transformed over time. For example, the invention of the microscope opened up a whole new world of microbial life to human understanding. However, redefining life might not solve this problem – because definitions refer to words and meanings, which are inherently flexible and dynamic. What we need is “an adequately general theory of living systems” and this requires expansion of our conception of life beyond what we observe on Earth. One such theory has been proposed already, in which life is described as “the activity of a biosphere,” where a biosphere is a “highly ordered system of matter and energy characterised by complex cycles.” The originators of this theory, Feinberg and Shapiro, hypothesise that the minimum requirement for life is simply an entropy gradient (change in amount of disorder over time).
If we take Feinberg and Shapiro’s theory to be true, we can imagine that life might evolve in exotic places, such as the atmospheres of giant stars or on the surface of neutron stars. Of course, the kind of life that could survive in such extreme environments would be light years from our current notion of life – perhaps so much so that we might be unable to recognise it. In a similar vein, the human mind is unable to comprehend shapes in four dimensions, so it is entirely possible that bizarre forms of life occupy higher dimensions inaccessible to us. For example, in Greg Egan’s Diaspora, giant growing carpets composed of carbohydrate building blocks in shapes like Wang tiles appear one-dimensional but when Fourier-transformed, reveal an incredible “thousand-dimensional frequency space” rich with life. It’s all pretty mind-trippy stuff.
Returning a bit closer to home: maybe there are multiple biosystems on Earth that remain hidden from us, so-called “shadow biospheres.” Massive portions of the Earth remain unexplored – like deep within the soil – which represent potential locations for life founded on alternative biochemistry or physical processes. For example, life might be based on silicon instead of carbon, or differing chirality. Perhaps even life based on weak forces like Brownian motion might exist. Another interesting point to consider is whether life can only exist in baryonic form – that is, in the form of matter we can detect. Some cosmologists predict that baryonic matter only comprises 4.6% of the total mass density of the universe – the remainder consists of dark matter and dark energy. Maybe some form of life extends into these dark realms of the universe.
Overall, while it may be especially important to humanity to find extra-terrestrial life similar to us, I contend that any discovery of life beyond our own planet would be equally as extraordinary, and potentially more mind-blowing and enriching. Therefore I believe we need to let go of our obsession with the “habitable zone,” and think more outside the box when it comes to the notion of life.