Posts Tagged‘life’

Chemical Evolution: Bridging the Gap Between Nothing and Life.

The question of where life came from on our Earth is one that has perplexed scientists and philosophers alike for centuries. Whilst we have really robust models for how life evolved to the point it’s at today how it first arose is still something of a mystery. Even if you adhere to the idea of panspermia, that the original building blocks of life were seeded on our planet from some other faraway place, that still raises the question of how that seed of life first came to be. The idea of life coming arising from the chemical soup that bathed the surface of the young earth is commonly referred to as abiogenesis but before that process took place something else had to occur and that’s where chemical evolution steps in.

We’ve know for quite a while that, given the right conditions, some of life’s most essential building blocks can arise out chemical reactions. The young earth was something of a massive chemical reactor and these such reactions were commonplace, flooding the surface with the building blocks that life would use to assemble itself. However the jump from pure chemical reactions to the development of other attributes critical to life, like cell walls, is not yet clear although the ever closing gap between chemical evolution and regular evolution suggests that there must be something. It’s likely that there’s no one thing responsible for triggering the explosion of life which is what makes the search for the secret all the more complicated.

However like all scientific endeavours it’s not something that I believe is beyond our capability to understand. There have been so many mysteries of the universe that were once thought impossible to understand that we have ended up mastering. Understanding the origins of life here on Earth will bolster our searches for it elsewhere in the universe and, maybe one day, lead us to find a civilization that’s not of our own making. To me that’s an incredibly exciting prospect and is one of the reasons why theories like this are so fascinating.

 

DNA Can Survive in Space, Re-Entry into Atmosphere.

There’s a few competing theories around how life came to be on our planet. One of them is the theory of abiogenesis, the idea that the building blocks of life assembled themselves from the primordial soup of the Earth to eventually give rise to life as we know it today. As an origin for all life it makes sense as it had to come from somewhere although whether or not it was how life came to be here is still up for question. Indeed the competing theory for how life originated here comes in the form of panspermia, the notion that our world was somehow seeded with life from planets elsewhere. Whilst it’s likely impossible to prove either of these theories they do lead to some interesting  areas of scientific research, the latter of which just bore some interesting fruit.

DNA HelixOne of the biggest questions with the idea of panspermia is whether or not the building blocks of life could survive in the harsh climate of space. We have known for some time that simple forms of life are able to tolerate the conditions of space for what seems like an eternity but given the time frames involved it’s far more likely that their genetic components would be the only things that would survive the long journey through space. Whether or not DNA could survive some of the most harsh conditions, like plunging back into the Earth’s atmosphere at re-entry speeds, is a question that researchers at the University of Zurich attempted to answer.

The results are quite intriguing, showing that the DNA molecules (which were applied to the outside of the craft with no shielding to speak of) was still viable upon returning to Earth. Whilst it’s far from a long duration spaceflight, the TEXUS launch system is a sub-orbital platform, it does show that DNA is very resilient to the harsh conditions experienced in space, lending credence to the idea that our Earth may have been seeded with genetic material of alien origin. Just how that material would have ended up finding it’s way here though is another question entirely, although it is an interesting one.

Genetic material lacks the capability to launch itself into space and so the only way it finds its way off a planet (bar ours) is to hitch a ride on a cataclysmic event. Large asteroids that impact a planet shoot up all manner of ejecta, some with enough energy to escape their planet’s gravity entirely. It’s a rare event, to be sure, however it’s happened often enough that we’ve got numerous bits of Mars scattered on Earth’s surface and likely bits of other planets that we don’t yet know about. If just a few of these kinds of asteroids hit Earth at the right time our origins of life might lie far beyond our own planet, or possible even our own galaxy.

It never ceases to amaze me just how resilient the building blocks of life are, being able to survive the harshest conditions and still remain viable. This then leads onto us finding life in all sorts of weird places, ones where you’d think it’d be impossible for anything to survive. I honestly can’t wait for the day when we find life on another planet, even if its microbes, as it will tell us so much about who we are and where we came from.

 

Life Without Water.

All life as we know it has one basic need: water. The amount of water required to sustain life is a highly variable thing, from creatures that live out their whole lives in our oceans to others who can survive for months at a time without a single drop of water. However it would be short sighted of us to think that water was the be all and end all of all life in our universe as such broad assumptions have rarely panned out to be true under sustained scrutiny. That does leave us with the rather puzzling question of what environments and factors are required to give rise to life, something we don’t have a good answer to since we haven’t yet created life ourselves. We can study how some of the known biological processes function in other environments and whether that might be a viable place for life to arise.

Supercritical CO2 Extraction

Researchers at the Washington State University have been investigating the possibility of fluids that could potentially take the place of water in life on other planets. Water has a lot of properties that make it conducive to producing life (as we know it) like dissolving minerals, forming bonds and so on. The theory goes that should a liquid have similar properties to that of water then, potentially, an environment rich in said substance could give rise to life that uses that liquid as its base rather than water. Of course finding something with those exact properties is a tricky endeavour but these researchers may have stumbled onto an unlikely candidate.

Most people are familiar with the triple point of substances, the point where a slight change in pressure or temperature can change it from any of its one three states (solid, liquid, gas) instantly. Above there however there’s another transition called the supercritical point where the properties of the gaseous and liquid phases of the substance converge producing a supercritical fluid. For carbon dioxide this results in a substance that behaves like a gas with the density of its liquid form, a rather peculiar state of matter. It’s this form of carbon dioxide that the researchers believe could replace water as the fluid of life elsewhere, potentially life that’s even more efficient than what we find here.

Specifically they looked at how enzymes behaved in supercritical CO2 and found that they were far more stable than the same ones that they had residing in water. Additionally the enzymes became far more selective about the molecules that they bound to, making the overall process far more efficient than it otherwise would have been. Perhaps the most interesting thing about this was that they found organisms were highly tolerant of this kind of fluid as several bacteria and their enzymes were found to be present in the fluid. Whilst this isn’t definitive proof for life being able to use supercritical CO2 as a replacement for water it does lend credence to the idea that life could arise in places where water is absent.

Of course whether that life would look like anything we’d recognise is something that we won’t really know for a long time to come. An atmosphere of supercritical C02 would likely be an extremely hostile place to our kind of life, more akin to Venus than our comfortable Earth, making exploration quite difficult. Still this idea greatly expands our concept of what life might be and what might give rise to it, something which has had an incredibly inward view for far too long. I have little doubt that one day we’ll find life not as we know it, I’m just not sure if we’ll know it when we see it.

The Origins of Life Become A Little Bit Clearer.

If you’re a scientifically minded individual then the question of how life arose is a perplexing one. We know a lot about what life requires to survive, water being the key substance to all life on earth, but how it came to be is still the subject of much debate. The theory of abiogenesis, which I personally subscribe to, posits that life arose out of the various chemical processes that were present back when our earth was just a billion years old. Then as life became more complex and organised the processes of evolution pressured by natural selection took over, sculpting life into the innumerable forms we see today. To lend credence to this theory we have to find ways in which biological processes could arise from non-biological constructs and new research has shown us just this.

A hydrothermal vent where life is thought to have had its beginnings, Credit to the Max Planck Institute of Marine Biology for this image https://www.mpi-bremen.de/en/Home.html

Image credit: Max Planck Institute of Marine Biology for this image https://www.mpi-bremen.de/en/Home.html

Research from the university of Cambridge has managed to replicate 2 distinct metabolic pathways using metal ions that would have been present in the oceans of a young earth. The two replicated pathways were glycolysis, the process by which glucose is turned into pyruvate and releases energy to form ATP (the energy transportation mechanism for all our cells) and the pentose phosphate pathway that generates carbon sugars. The process to replicate these metabolic pathways was relatively simple, they had a solution that closely matched what we believe the early oceans of the earth were composed of and added in solutions that were known to be starters for metabolic processes. They were then subjected to conditions you’d find near a hydrothermal vent for 5 hours and the resulting solutions analysed for the resulting products. The results, whilst not being earth shattering, are incredibly intriguing as they lend credence towards certain theories about the evolution of life on earth.

Primarily it points towards early life not being reliant on ribonucleic acid (RNA) as this is currently responsible for creating many of the enzymes that speed many of the complex biological reactions that life makes use of. This research shows that these processes could have arisen by themselves without the need for RNA and could possibly be the building blocks of RNA itself. Whilst this doesn’t exactly tell us how life arose out of the primordial soup that was present on an early earth it does point towards an origin where the complex processes arose out of the primordial soup that once blanketed our earth.

Like most research of this nature whilst the results are impressive more work needs to be done to ascertain just what’s going on. The experiment has recreated the end product from a known starting state however they haven’t shown what the intermediary products are. Knowing these will give us insight into just how similar the current biological processes are to the ones created in the lab, with any discrepancies providing even more opportunity for additional research.

It’s a small step towards understanding the origins of life but a crucial one. The more we understand how life came to be here the more readily we’ll be able to identify other such places in our universe, possibly even those in our cosmic backyard. Our understanding of the origins of life are still in their infancy but we’re creating an ever more clear picture of where our distant ancestors came from.

Enceladus’ Watery Secret Confirmed.

The search for life beyond that of our planet is a complicated one. As it stands we only know of life arising in a particular way, one we can’t be sure isn’t unique in the universe. Still it’s the best model we have to go by and so when we search for life we look for all the same signs as we do for anywhere here on Earth. The one constant that binds all life on Earth is water and so that is why we search so fervently for it anywhere in the solar system. Surprisingly there are many places to find it but none are more spectacular than Saturn’s moon Enceladus.

Enceladus CassiniEnceladus is a strange world, truly unlike anything else in our solar system. Its surface is incredibly young, mostly devoid of the numerous pockmarks that are common among other atmosphereless celestial bodies. This is because it’s in a constant state of change, it’s icy surface splitting and cracking open to reveal a new unsullied surface. Enceladus is like this because Saturn’s massive girth warps the tiny moon as it makes its orbit, generating incredible amounts of heat in the process. The same process is responsible for the amazing cryovolcanoes that dot its south pole, spewing forth tons of water per day into the depths of space. Whilst it’s easy to confirm that there’s liquid water somewhere on Enceladus (those cryovolcanoes aren’t magical water spouts) the question of where the reservoir is, if there even is one, has been the subject of much scientific study.

It has long been thought that Enceladus was host to a vast underground ocean although its specifics have always been up for debate. Unlike Europa which is thought to have a layer of liquid water underneath the ice (or a layer of “warmer” ice) the nature of Enceladus’ ocean was less clear. However data gathered by the Cassini spacecraft during its flybys of the moon in 2010~2012 show that it’s very likely that there’s a subsurface ocean below the area where the plumes originate. How they did this is quite incredible and showcases the amazing precision of the instruments we have up in space.

The measurements were made by using the radio communications between Cassini and Earth. These stay at a relatively fixed frequency and thus any changes in the craft’s speed will manifest themselves as slight Doppler Shifts in the frequency. This is the same principle behind how the sound of an approaching ambulance changes as it gets closer and farther away and it allows us to detect even the smallest changes in Cassini’s speed. As it turns out when Cassini flew over Enceladus’ south pole, which has a great big depression in it (meaning there’s less gravity at that point) the change in speed was far less than what we expected. What that means is there’s something more dense below the depression that’s making up for the lack of matter in the depression and, since water is more dense than ice, a giant hidden sea is a very plausible explanation.

There may be other explanations of course, like a giant deposit of heavy elements or just plain rock, however the fact that there’s water gushing up from that location gives more credence to the theory that it’s an ocean. The question now turns to nailing down some of the other variables, like how big it actually is and how the water gets to the surface, which I’m not entirely sure the Cassini craft is capable of determining. Still I wasn’t completely sure it was capable of doing this before today so I’m sure the scientists at NASA have some very interesting ideas about what comes next for Enceladus.

Lake Vostok is a Scientific Boon, No Matter What We Discover (or Don’t).

Life is a strange thing. No matter where you go on Earth as long as there’s water you’re guaranteed to find some form of life there. Current scientific theory posits that the reason behind this is that after the initial conditions were met to instantiate life it then set about diversifying itself into many environments in order to out-compete its rivals and become the dominant species in its chosen niche. As far as we know it’s nigh on impossible for life to originate in some of the conditions we find it in and some are just so inhospitable that we don’t believe life could sustain itself in such conditions for any reasonable amount of time.

Lake Vostok

One such location is Lake Vostok a body of water that’s buried beneath some 4KMs worth of ice. Based on radar imaging of the ice flow we believe that this particular lake has been cut off from the outside world for some 15 million years although the water is probably closer to 13,000 years old, due to the flow of ice around it. The water at the bottom remains liquid due to the enormous amount of pressure bearing down on it from the several kilometre thick ice sheet above it even though its average temperature is about -3 degrees centigrade. The water there is also unlike any other water in the world containing about 50 times the amount of dissolved gasses (mostly oxygen and nitrogen) making it quite a unique environment.

It’s interesting for a couple of reasons, the most important of which is whether or not there is life down there. The conditions are extremely inhospitable since no sunlight reaches it, the temperature would kill most microbial life and due to its isolation from the outside world it’s likely to be very nutrient poor. Now it’s not like we haven’t seen conditions like this before and then proceeded to find life there (indeed there’s a whole classification dedicated to these types of creatures: Extremophiles) but the question of whether or not there’s life in Vostok is important due to its implications.

If we find life there, we have a few other places in the solar system which could be worth investigating.

This is why the scientific community erupted in a clamour of joy recently when scienticists from the Lake Vostok outpost announced that they had found life in their drill samples and it contained DNA that was only 86% similar to current life on Earth. Discovery of such an alien form of life would mean there’s a good possibility that the oceans under the surface of our gas giant’s frigid moons might also contain similar levels of life. It would then open the path to missions like Cryobot which, up until a discovery like this, were scientific long shots that have a hard time justifying the giant budgets required to make them a reality.

Unfortunately though the announcement was somewhat premature as the bacteria discovered has turned out to be a contaminant putting the kibosh on all the excitement. It’s an unfortunate symptom of scientific reporting as the results had not yet gone through peer review which is designed to catch mistakes like this. It doesn’t mean the work they’re doing there is all for naught though as it simply means that they need to be more cautious before releasing information lest they cause another stir like they just did. Problem is without public interest its hard to keep things like this funded which is what causes scientists to release early results before the proper peer review process can take place.

However even if they don’t find life down there that will still be something of major scientific significance. As I said before we seem to trip over life wherever we go on this planet and so the current upper and lower bounds on where it can exist are a little fuzzy. Finding a place on earth where life simply can’t survive would mean that we could focus our efforts on the search for life elsewhere and potentially not spend ludicrous amounts of money and time foraging for life in places which it simply would not be able to exist in. We’re still a fair way off from knowing either way on life in Lake Vostok but no matter the outcome it will still be worth pursuing.

I feel the scientist’s pain on this one, I really do. On the one hand you want to do solid, valuable science that will be a major influence on future studies. However by the same token you have to generate enough interest in your area in order to secure funding to keep doing just that and that puts a lot of pressure on you to release results like this before they’re ready for prime time. Thankfully the scientific process works to ensure that inaccurate information doesn’t remain like that for long.

Europa, We Should Attempt Landings There.

Carl Sagan is quote as saying that “life looks for life”. Indeed if our own history is anything to go by we’re in a constant state of searching out other forms of life and just recently we’ve extended that search beyond the confines of the world that gave rise to us. So far our search beyond our home world has proved fruitless as we’ve been unable to find any direct indications of life on any other heavenly body that’s within our reach. Thus we find Earth in what appears to be some great isolation which is a somewhat disconcerting notion given the age of the universe and the number of potential habitable planets in our galactic backyard. We should not be discouraged however as our quest to find life elsewhere is only just beginning.

Of all the other heavenly bodies that inhabit our solar system there’s one that stands out as the best candidate for housing life. Now if I was to ask the question of which body it was most people would respond with Mars as it’s the only planet that resembles Earth in some fashion, with the next closest candidate being the raging hell of Venus. It’s not a bad guess either as we’ve proven several times over that there was once vast amounts of water there and there’s still a very good chance there’s liquid water present today. However Mars is a very inhospitable place so much so that the best hope for life there is nothing above microbial and even that seems like a far reaching prospect.

Europa on the other hand is quite the curiosity. As far as moons go it really is something out of left field being a striking combination of bright whites and browns. It’s surface is also one of the smoothest in the solar system thanks to it being made almost entirely of water ice. That doesn’t mean it’s featureless however as the entire surface is criss-crossed with fracture lines from the giant ice sheet breaking apart and reforming. Many have speculated that this is because the surface actually lies on top of a giant subsurface ocean and when cracks form the ocean rushes up to fill it, forming the characteristic lines. It’s this undersea ocean that makes Europa one of the best candidates for life forming outside of Earth and recent studies show it just got a little better.

The potential ocean on Europa would be some 3KM below the surface, quite a ways away from any direct sunlight or other potential energy sources. It’s theorized then that the ocean is kept liquid by the tidal flexing that Europa undergoes every time it orbits Jupiter which could also drive the same kinds of volcanism processes that gives rise to life in the depths of our oceans. However recent research shows that there’s potential for some subsurface lakes that are much closer to the surface than the great ocean below. These lakes would have a higher rate of churn between water and ice providing a much a habitat that’d be more nutrient rich and hopefully more hospitable to life. Of both these recently modelled oceans and the great subsurface ocean haven’t yet been conclusively proven, but that just makes Europa a really tantalizing target for exploration.

Quite a few missions have swung past Europa already with the most detailed analysis being done by the Galileo craft from 1995 to 2003. However we haven’t been back there recently save for a short flyby by the New Horizons craft that imaged it on its way to Pluto. If we were to go back there my favourite mission candidate would be the Crybot style mission. In essence it’s a probe that’s fitted with a giant heater on the front of it, capable of plunging through several kilometres of ice. Once it broke through it would then deploy a small autonomous underwater vehicle that could investigate the subsurface ocean. This mission hasn’t got past the back of the napkin style planning stages yet, but I’m hopeful that we’ll one day attempt such a mission.

Europa is a curiosity unlike any other in our solar system and there’s so much we could learn from it if we were to send a mission there. Whilst the environment there isn’t really human friendly (the radiation at the surface is quite large, about 450 chest x-rays a day worth) it’s definitely within our current capabilities of robotic exploration. I know that one day we’ll see a dedicate mission there but until then I’m quite content to continue fantasizing about the undersea world that it contains and the tantalizing possibility that as of yet unknown life forms exist there.

Arsenic Consuming Microbes: Life Not As We Know It.

I was just about to knock off one of the many RSS feeds I had a massive backlog on when I noticed an article about NASA making a pre-announcement about a press conference they were going to have today. Usually this stuff isn’t front page news but this one had just the right combination of words to send us space nuts (and a good chunk of regular people too) into wild speculation about what NASA might have found. Even more interesting was the fact that one of my friends sent me a rabid SMS directing me to the same article. Something told me that whilst this wouldn’t be your run of the mill NASA press conference there was something big on the horizon, leaving my mind to buzz around all the possibilities.

NASA was not one to disappoint on this occasion.

Researchers at NASA’s Astrobiology Institute have discovered a microbe, native to California’s Mono Lake (a highly inhospitable place), that can survive and thrive by replacing one of the essential building blocks of life with an element that’s highly toxic: arsenic. The bacteria, known as GFAJ-1, was known to be arsenic resistant but researchers took it one step further by depriving the microbes of all phosphorus and flooding their environment with arsenic. The result was that not only did the bacteria survive they thrived, continuing to multiply as if nothing had changed in their environment. Further analysis of the bacteria showed that they had incorporated the arsenic into their DNA where the phosphorus should have been. This throws so many things into question and will change the way we search for alien life out in the universe.

The space and science news sites are abuzz with the implications of the discovery and what it means for the future of astrobiology. The news was so big that it even made the morning news here in Australia something that even the shuttle launches struggle to accomplish. Whilst this announcement isn’t as fantastical as some had hoped for (first contact being amongst them) we’re still at a turning point in our understanding about how life formed here on earth and how it can form elsewhere in the universe.

The discovery is interesting as prior to finding these microbes all life on earth has needed to use 6 building blocks in order to survive: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. Arsenic is just below phosphorus on the periodic table so it shares quite a lot of properties with it and that similarity means it can be substituted into some biological reactions. However arsenic is far more reactive than phosphorous and this means that it is highly toxic to almost every life form on the planet. This bacteria however seems to have developed the ability to use arsenic when it is in a phosphorus poor environment and even has the ability to switch back to phosphorous should it become plentiful again (it actually seems to prefer it).

As with any big discovery this one is not without its critics. Steven Benner, a chemist from the Foundation for Applied Molecular Evolution, makes the point that whilst these bacteria were phosphorus starved there were traces of it available. Enough possibly to sustain these bacteria in the arsenic rich environment. Additionally should these bacteria be incorporating arsenic into their DNA it would be in the form of a arsenate, an ester of arsenic. Such a compound would hydrolyse in water making such arsenate based DNA unstable. He hypothesises that the arsenic is being used in some other fashion, possibly in a way that we do not yet understand. The research is of course continuing and will address these concerns.

We’ve known for a long time that life can develop in places we’d long thought it was impossible to do so but this discovery is something on a whole new level. Showing that a life form, even if it’s a simple one, can replace one of the fundamental building blocks of life with something thought to be toxic means we have to rethink the way in which we look for life here and out in the vastness of space. The prospect of finding life on other planets and moons here in our own solar system just got more possible as our understanding of how life can thrive undergoes a radical paradigm shift. I can’t wait to see how this develops and I’m sure this isn’t the only bacteria out there capable of feats like these. Who knows what kind of alien life we’ll find right here in our own little rock called earth.

Gliese 581g: The Tantilizing Possibility of Life Elsewhere.

For all the exploration of space we’ve done to date we have still found no evidence of life outside our own biosphere. We’ve found many of the building blocks scattered around our solar system but all our attempts to find even the most simplistic of life forms have been met with failure. Still with the raw ingredients being so common in just our own back yard it follows that there’s a high likelihood that somewhere in the deep blackness of space lies another planet that teams with life like our own. Still with the number of exoplanets only numbering in the hundreds and the technology strongly skewed to finding large gas giants close to their parent stars we had yet to come across another planet that life as we know it could call home. That was until just recently.

The news spread like wildfire when astronomers at the Keck Observatory in Hawaii released information regarding a planet who’s characteristics looked very familiar:

An enticing new extrasolar planet found using the Keck Observatory in Hawaii is just three times the mass of Earth and it orbits the parent star squarely in the middle of the star’s “Goldilocks zone,” a potential habitable region where liquid water could exist on the planet‘s surface. If confirmed, this would be the most Earth-like exoplanet yet discovered and the first strong case for a potentially habitable one. The discoverers also say this finding could mean our galaxy may be teeming with prospective habitable planets.

“Our findings offer a very compelling case for a potentially habitable planet,” said Steven Vogt from UC Santa Cruz. “The fact that we were able to detect this planet so quickly and so nearby tells us that planets like this must be really common.”

Vogt and his team from the Lick-Carnegie Exoplanet Survey actually found two new planets around the heavily studied red dwarf star Gliese 581, where planets have been found previously. Now with six known planets, Gliese 581 hosts a planetary system most similar to our own. It is located 20 light years away from Earth in the constellation Libra.

Gliese 581 is one of the most studied stars in our sky with no less than 6 exoplanets being discovered orbiting it. It’s a red dwarf star meaning it’s much less bright than our sun and is quite a bit less massive. Still the planets that are orbiting it look very familiar with one of it’s planets being very much like Venus (very close to the sun, probably a planetary hot house) and another quite like Mars (much further out, could potentially have or hosted life). The Gliese 581 system provides evidence that our kind of solar system, one with a diverse range of planets and several habitable candidates, is quite possibly very common. Gliese 581g is exciting because unlike it’s two sister planets it’s right smack bang in the middle of the habitable zone, and with that comes the chance of life.

In this picture Gliese 581 resides right near the bottom with the habitable zone being quite close to the parent star, right up to a mere 10% of the distance from earth to our star. Gliese 581g lies right in the middle of this zone and due to the close proximity this leads to a few interesting characteristics. A year on Gliese 581g is a little over 36 days long which is amazing when you consider Mercury, the closest planet to our star, still takes around 88 days to complete one rotation around our sun. Because of this close proximity to its parent Gliese 581g is also tidally locked to it, forcing the same side of the planet to always face the red dwarf star. Because of this I do not believe that life as we know it could exist on this planet. However that does not mean life could not survive (or even thrive) there.

Our version of life is the only model we’ve got to go on right now since we really haven’t come across anything different. Whilst many forms of life might look completely alien to us they all shared the same basics that enabled other life to thrive on earth. The key to all life as we know it is water as nearly everywhere on earth where there’s some form of water we tend to find life teaming there, even in the most inhospitable conditions. Gliese 581g is big enough that it should be able to hold onto a tenable atmosphere and the temperatures at the surface should be sufficient to support liquid water. However the weather on the surface would be anything but calm as cold wind from the night side of the planet would be constantly blowing thanks to the constant heating of the day side. The terminus boundary between eternal night and day could serve as a habitable strip all across the entire planet, but this is where things get tricky.

The day/night and seasonal cycles of this planet have greatly influenced how life formed on this planet. Gliese 581g would have none of these things with no orbital tilt to speak of to generate the seasons and either constant day or night depending on which side of the planet you were on. This means that any life that evolved there would have to cope with such conditions, eliminating the need for a circadian rhythm and any kind of seasonal behaviour. Since nearly all species of life on earth rely on both these mechanisms for survival the life on Gliese 581g would be wildly different from our own, probably lacking the need for sleep and being almost constantly active. Of course there would be other selection pressures at work here as well, leading to even more alien forms of life.

Is life guaranteed to exist there as so many articles claim? Not in the slightest. There are so many factors that lead up to the development of life that we just can’t be certain one way or another. There are some theories that the Moon played a large part in kick starting life on earth and right now we can’t tell if Gliese 581g even has one. There’s also the real possibility that our new celestial cousin has a thick, acidic atmosphere killing any early stages of life well before they had the chance to adapt. Until we can get more data on the planet anything we say about life there is purely speculative and really it will always be that way until we send a probe there to investigate.

Still Gliese 581g means so much to us for what it symbolises. It shows us that our solar system isn’t unique in the galaxy and gives evidence to support the idea that there are untold numbers of planets that are potentially habitable. We’re on the brink on discovering many, many more of planets like Gliese 581g and each one will give us some insight into the formation of our universe and ultimately life itself. We’re still a long way from being able to explore them for ourselves but I know that one day we mere humans will journey to those stars and revel in their beauty.

Antarctica, Europa and Life Not as we Know it.

Life is a tricky thing to get right. As far as we know right now we’re a completely unique in this universe and the conditions that led to us being here are both mysterious and endlessly intriguing. Whilst I won’t dive into the debate on science vs religion here (I’ve already done that) my own personal views are ones of abiogenesis, or more simply the idea that the complex life that we know and love today arose from a long chain of events that started with just the basic elements of the universe. Whilst there’s still a lack of consensus around the actual mechanisms that would have led to this happening the basic idea remains the same.

This is mostly due to the lack of another point of data, I.E. us encountering life that arose on another planet. So instead we start looking around our own earth to find examples of how life got started and where it exists. We’re discovering more and more that environments that we thought were completely incompatible with life are actually teaming with creatures that seem almost impossible to us. From complex curiosities like the Yeti Crab and the Flashlight Fish to bacteria that thrive on the heat radiated from black smokers it seems that once conditions are favourable to life you’ll end up finding it pretty much anywhere.

Still there are some places you just don’t expect to find life, like 185 meters below an ice sheet:

Researchers in Antarctica got a surprise visit from a creature in a borehole 185 meters (600 feet) below the Antarctic ice, where there is usually no light. A Lyssianasid amphipod, a shrimp-like creature can be seen swimming in this video. A NASA team had lowered a small video camera to get the first-ever photograph of the underside of an ice shelf when the curious little 7 cm (3- inch) shrimp stopped by to check out the equipment. Scientists say this could challenge the idea of where and how forms of life can survive. Anyone else thinking Europa?

To say that little shrimp was completely unexpected would be putting it lightly as for all we knew there was absolutely nothing down there capable of supporting life any larger than simple bacteria. They also found what appears to be the tentacle of a jellyfish tangle around the cord of the camera suggesting there’s not only life but also some amount of diversity down there. So whilst this might be cool and all why is everyone asking about Europa?

For those of you not in the know Europa is a moon of the planet Jupiter and is only a bit smaller than our very own Moon. It’s quite a striking thing to look at as it’s surface looks like a round ice cube that’s covered in dust, very different to our closest neighbour who’s an even shade of dull gray. When we get up and close to it we see it’s covered in these long lines which look scarily similar to ice sheets on earth. As it turns out Europa’s crust is actually a solid layer of ice that’s a few kilometers thick and under that is an internal ocean that, as our best guess goes, is tens of kilometers deep. The lines on the surface are cracks that opened up to the internal ocean below where upon water from below swelled up to fill the gap.

What the scientists’ unexpected visitor tells us is that there is the possibility for complex life to evolve in places where light cannot reach it, and that means that there’s a chance that life evolved in the sea under Europa.

You may be wondering how life could evolve in a place that’s covered by kilometers of ice in a frigid sea so far from the sun. Well as it turns out thanks to its giant parent planet and slightly non-circular orbit Europa is constantly being squeezed and pulled every time it completes one round trip. This has the effect of creating an extreme amount of internal heat that not only serves to keep the internal ocean liquid but could also serve to generate the volcanism that some theories believe is required to create life. Out of all the other places in the solar system this is probably the only other place where life could potentially exist based on the evidence we’ve gathered here on earth.

It’s discoveries like this that get me all excited about the infinite possibilities of the universe. Whilst there’s no evidence that there are any other intelligent life forms out there the evidence is getting stronger and stronger that it’s there, we just have to go and find it. I know that one day we’ll send a probe to Europa to see what is really under that thick ice blanket and should we find life there you can bet your bottom dollar that it will change how we view ourselves and our place in the universe forever.