There’s many ways to look for life on other planets. Most of our efforts currently focus on first finding environments that could sustain life as we know it which is why the search (and subsequent discovery) of water on other celestial bodies is always a cause for celebration. Once we’ve got a target though the search needs to become more nuanced as we have to seek out the clues that life leaves behind or the blocks that build it. For life as we know it one of the first things we can look for is the presence of organic molecules, the essential parts that make up all of life as we know it. One of these such molecules is methane, reknown for being a component in flatulence, something which Curiosity recently detected on Mars.
Methane, and other organic compounds, don’t necessarily require life in order to form however their presence does indicate that there was an environment favourable to life at one point in time. For Mars this was some time ago, on the order of billions of years, and so it’s highly unlikely that any remaining methane is due to microbial activity. However there has to be some local source of methane near Curiosity as it detected a ten fold spike in the amount of methane in Mars’ atmosphere, something which it has never seen before. Additionally Curiosity detected other organic molecules in a rock it drilled into recently, indicating that there was a time when organics must have been prevalent across the entire surface of Mars.
The discovery was made sometime ago however the researchers needed to rule out the possibility that the reading was caused by organics that were trapped in Curiosity’s sensors from Earth. Things like this happen more often than you think as whilst we take every precaution to ensure that there isn’t any contaminations on craft like this it’s inevitable that the sensors, all of which are highly complex machines, end up having stray molecules trapped within them. Because of that however we’ve gotten pretty good at identifying when things came along for the ride and this particular methane spike didn’t originate from Earth.
The organics in the rock are most intriguing however as they tell a story of Mars’ atmosphere that stretches back to the point where it still held liquid water on its surface. The ratio of isotopes in the water (which I talked about yesterday in regards to the discoveries Rosetta has made) indicates that the mineral formed some time after Mars lost much of its water, if we assume that the water on Mars and Earth came from the same place. However the ratio is also radically different to the water in Mars’ atmosphere today indicating that it formed before Mars lost the rest of its surface water. It will be interesting to see how this sample compares to other places around Mars as it will paint a detailed picture of the planet’s surface over time.
It seems like it will be only a matter of time before we find a large source of water on Mars, buried deep beneath the surface somewhere. From there we’ll have an exciting period of analysis to determine if microbial life still thrives on what appears to be a dead planet. Unfortunately that’s not likely to happen any time soon, at least not until we get people there anyway, but with NASA recommitting themselves to such an endeavour it might come sooner than many first thought. Honestly I can’t wait for that to occur as it will shed so much light on how life evolves and, possibly, what it can become.
The origin of Earth’s water is still something of an open debate. The popular theory at the moment is that the primordial Earth was far too hot to contain any form of liquid water, its molten surface still reeling from the cataclysmic events that led to its creation. However others postulate that the water was trapped deep below the surface, only to arise later on as the Earth cooled and an atmosphere developed. It’s an interesting question not only because of how fundamental water is to life but also because we seem to have a lot more of it than any other planet in the solar system. Thus the question of where it came from, and why it’s managed to stick around for so long, is one of continuous scientific enquiry, including such missions as the recently celebrated Rosetta probe.
If we run with the theory that Earth’s water came from some extraplanetary source then the question turns to what the original source might be. Comets seem like a good candidate as they’re primarily water ice by composition and were far more common during the early stages of Earth’s life than they are now. However measurements of isotopes within water of several comets, including Halley, Hyakutake and Hale-Bopp has shown that they are not likely the primary source of water that’s currently on Earth’s surface. The composition of water found on asteroids and other water formed minerals on the Moon seem to indicate that a source closer to home is far more likely which Rosetta’s latest data appears to confirm.
The comet that Rosetta was investigating, the romantically named 67P/Churyumov–Gerasimenko, has a ratio of isotopes that is completely different to anything that’s seen on Earth. The reason that this is important is due to it’s orbit as 67P is what we call a Jupiter class comet, a collection of various comets that have orbits that don’t extend far past Jupiter. It was thought that these kinds of comets would have been more likely to have been involved in the creation of Earth’s oceans than comets from further out, due to their proximity. However 67P, with its wildly different composition to Earth (and even other bodies in the same vicinity), lends credence to the idea that comets aren’t the likely source of Earth’s oceans. Indeed it’s far more likely that water and minerals trapped in asteroids are the likely source, based on how similar their composition is.
Now this doesn’t rule out comets completely as there’s potential for further out Kuiper belt class comets to have the composition we’re looking for but it’s looking far more likely that objects from within the asteroid belt are responsible for the oceans we have today. What the mechanism was for them making their way to Earth, whether it was early on in the cataclysmic forming of our solar system or later on when things calmed down, is something that’s still an open question. It’s one we might also have answers to very soon as Dawn is scheduled to arrive at Ceres early next year, the biggest object in the asteroid belt. What Dawn finds there might be the key to unlocking the secrets of our Earth’s oceans and, potentially, the asteroid belt itself.
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.
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.
It may seem like scientists spend an inordinate time studying water but there’s a pretty good reason for that. Water is fundamental to all forms of life on Earth so understanding its origins and what roles it plays is crucial to understanding how life came to be and where we might find it. The vast majority of Earth’s water is contained in its oceans which were thought to have formed when comets bombarded its surface, seeding them across the world. However recent research has shown that the oceans may have formed in a different way and that Earth may have much more water contained in it than previously thought.
A recent study done by Steven Jacobsen and his team at Northwestern University has revealed that Earth has a subsurface reservoir that may contain 3 times the volume of the Earth’s surface oceans. They discovered this information by using data from a wide variety of seismometers, those instruments that measure the intensity of the pressure waves of earthquakes, and figuring out how the waves travelled through the Earth’s interior. This is nothing new, it’s how we’ve figured out the rough compositions of the different layers of the Earth’s inner layers previously, however Jacobsen postulated that water in ringwoodite would slow the waves. After testing a sample of ringwoodite to confirm this theory (shown above) his team found data to support the existence of a large layer of ringwoodite in the Earth’s mantle. Whilst this isn’t a subsurface ocean like some heavenly bodies in our solar system have it is a rather interesting discovery, one that supports an entirely different theory of how our surface oceans formed.
The initial hypothesis (at least the one I’m familiar with) is that the Earth bound itself together out of all the varying bits of debris that existed after the sun had formed itself. At this point Earth was a ball of lava, a fiendishly unfriendly environment devoid of any kind of life. Then, as the planet cooled, comets rained down on its surface, supplying the vast amounts of water we now see today. The discovery of this layer of ringwoodite on the other hand suggests that the water may have been present during the initial formation and that instead of other comets providing all the water it instead seeped up, filling all the crevices and crags of the Earth’s surface. It’s interesting because it now links Earth more directly to our other celestial neighbours, those which you’d never consider Earth-like at all.
Saturn’s Europa and Jupiter’s Ganymede for instance are both hypothesized to have vast bodies of water under their surfaces. Up until this discovery you would be forgiven for thinking that their initial formation was likely due to their immediate environment (I.E. those massive gas giants right next to them) however it’s more likely that all heavenly bodies form along a similar path. Thus oceans like ours are probably more likely than not for planets of similar size to ours. Of course there are also numerous other factors that can push things in one way or another (see Mars and Venus for examples of Earth like planets are nothing like Earth) but such similarities really can’t be ignored.
In all honesty this discovery surprised me as I had always been a subscriber to the “comet bombardment” theory of Earth’s oceans. This evidence however points towards an origin story where water formed a core part of Earth’s structure, only to worm its way to the surface long after it cooled. Come to think of it this probably also explains (at least partially) how Earth’s atmosphere likely came to existence, the gases slowly seeping out until it was blanketed in carbon dioxide, only to be turned into the atmosphere we know today by plants. I’m keen to see what other insights can be gleaned for this data as I’m sure this isn’t the only thing Jacobsen’s team discovered.
Correction: My good friend Louise correctly pointed out that our atmosphere started off being almost completely carbon dioxide and only had the composition we know today thanks to plans. She also pointed out I used the wrong “it’s” in the title which, if I didn’t know any better, would say to me that she wants to be my copy editor
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 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.
There’s an argument to be made that we should be in total control of everything that goes into our bodies and I support that idea to an extent. However when your decision can adversely impact the lives of others that’s when I support intervention which is why I wholly support compulsory vaccination. This also extends to my support of water fluoridation as, again, whilst there’s numerous arguments that can be made against it the fact that it will benefit so many at almost no risk to others means it’s a net positive for us as a whole. Of course this hasn’t stopped a vocal minority from claiming all sorts of horrific things happening due to water fluoridation the worst of which being that it’ll make you stupid.
A single article on Huffington Post usually wouldn’t warrant my attention, it’s not exactly known as the bastion of sound scientific reporting, but it came across my path not long after a similar post from a Facebook page called The Mind Unleashed claiming that fluoride in water lowered IQ significantly. Because I couldn’t help myself I spent a good couple hours tracking down the research and other articles relating to it. Just like most reporting on scientific discoveries this one is completely overblown and, when you dig into the details, doesn’t support the conclusions that many would draw from it.
I’d love to say that I was surprised by this but this isn’t my first rodeo with bullshit.
A review of water fluoridation studies done researchers at Harvard University concluded that whilst water fluoridation may affect IQ scores the levels that were detected in the study were at least 10 times higher than what’s found in artificially fluoridated water. Additionally the studies failed to control for other variables which are known to affect brain development and IQ scores like the fact that many of the studies were conducted in highly polluted areas in China. Funnily enough the control group in one of the studies were consuming water with similar levels of fluoridation to that of developed countries which shows pretty clearly that the current dosage levels work without the noted side effects.
On the flip side there’s a lot of research that shows water fluoridation reduces cavities in children and adults by a significant percentage, even in those who already have access to it through other means (like toothpaste or as an additive in other food staples). Indeed if you’ll allow me to get hand wavy for a bit there’s evidence to suggest that the average IQ has been trending upwards for the last hundred years or so called the Flynn effect. If fluoridation had a significant impact on IQ scores then we should’ve seen a harsh dip around 1960 when in fact we see the exact opposite. Now correlation does not equal causation but it’s a pretty good indicator that the negative isn’t true.
I could go on but the fact is that water fluoridation works incredibly well as a public health policy, greatly helping those who are at risk at developing tooth cavities and even those who’d consider themselves not needing it. Therefore removing it would cause harm to those who can least afford it to happen to them and that’s why bad science reporting like this needs to be exposed for what it is. I know I’m probably preaching to the choir here but I know how hard it can be to debate people who spout nonsense as fact and hope that you can use this as a reference rather than having to disappear down the research hole that I did.
Growing up in a rural area meant that my Internet experience was always going to be below that of my city living counterparts. This wasn’t much of an issue for a while as dial-up was pretty much all you could hope for anywhere in Australia however the advent of broadband changed this significantly. From then on the disparity in Internet accessibility was pretty clear and the gap only grew as time went on. This didn’t seem to change much after I moved into the city either, always seeming to luck out with places that connected at speeds far below the advertised maximum that our current gen ADSL lines were capable of. Worst still they almost always seemed to be at the mercy of the weather with adverse conditions dropping speeds or disconnecting us from the Internet completely.
My current place of residence never got great speeds, topping out at 6Mbps and only managing to sustain that connection for a couple hours before falling over. I can expect to get a pretty stable 4Mbps connection most of the time however the last few days have seen Canberra get a nice amount of rain and the speeds I was able to get barely tickled 1Mbps no matter how many times I reconnected, reset my modem or shouted incoherently at the sky. It was obvious then that my situation was caused by the incumbent weather, filling my local Telstra pit with water which sent the signal to noise ratio into the ground. Usually this is something I’d just take on the chin but this situation was meant to be improved by now if it wasn’t for the current government.
Prior to the election my area was scheduled to start construction in October last year however it became one of the areas that disappeared off NBNco’s deployment map shortly after the Abbot government came into power. This meant I would then come under their revised plan to bring in FTTN through VDSL which has the unfortunate consequence of leaving me on the known-bad infrastructure in my street. So my speeds might improve but it’d be unlikely that I’d get “at least” 20Mbps and I could guarantee that every time it rained I’d be in for another bout of tragic Internet speeds, if I could connect to it at all.
The big issue with the Liberal’s NBN plan is that my situation is by no means unique and indeed quite typical thanks to the aging infrastructure that is commonplace throughout much of Australia. Indeed the only place that I know gets speeds as advertised for their cable run are my parents who still live in a rural area. The reason for this is because the copper is new out there and is quite capable of carrying the higher speeds. My infrastructure on the other hand, in a place where you’d expect it to be regularly maintained, doesn’t hold a candle to theirs and will continue to suffer from issues after we get “upgraded”.
A full FTTP NBN on the other hand would eliminate these issues providing ubiquitous access that’s, above all, dependable and reliable. The copper mile last run that the majority of Australia will end up using as part of the Liberal’s NBN just can’t provide that, not without significant remediation which neither Telstra nor the government has any interest in doing. Hopefully the Liberal government wakes up and realises this before we get too far down the FTTN hole as it’s been shown that the majority of Australian’s want the FTTP NBN and they’re more than willing to pay for it.
The moon is our closest celestial neighbour and as a consequence is by far one of the most studied celestial bodies. By all accounts it’s a barren wasteland, covered in numerous pot marks from the asteroids that have bombarded it over its lifetime. However the more we investigate it the more we find out that, whilst there’s almost no chance of life being present there, many of the resources that life depends on can be found there. Whilst we’ve known for a while that it would be possible to extract water from the regolith on the surface new observations from NASA’s Moon Mineralogy Mapper instrument aboard India’s Chandrayaan-1 have revealed that there might be actual water on the Moon, just waiting there for us to use.
The initial implications of this are obvious. Water is one of the fundamental resources required for any human based space mission and the amount required usually has to be brought along for the ride. This means the payload capacity used for bringing water along can’t be used for other things, like additional supplies or more equipment, and presents a big challenge for long duration flights. Having a source on the Moon means that any potential bases or colonies established there would have much less reliance on resupply missions from Earth, something which is the primary limiting factor for any off-world colonies that we attempt to establish.
However that pales in comparison when compared to what water on the Moon means for space in general: it’s a primary component for rocket fuel.
Water’s basic composition is hydrogen and oxygen which are the components which power many of the liquid fuelled rocket engines that operate today. Of course in their bonded state they’re not a ready to use propellent exactly so a process is required to break those bonds and get those atoms separated. Thankfully such a process exists, called electrolysis, which splits water down into its component gasses which can then be stored and later used to send rockets on their way. Of course such a process relies on a stable power source which would likely be some like of large solar array backed up by a large battery bank to last through the 2 week long darkness that regularly blankets half the surface.
The biggest challenge that many of the long duration or large payload missions face is the fact that they require more fuel. Carrying more fuel unfortunately also means carry more fuel and there’s points of diminishing returns where you’re spending far too much fuel just to get yourself out of our gravity well. Having a refuelling station or the Moon (or, even better, constructing and launch payloads from there) would mean that we would put larger payloads into space and then push them to the outer reaches of the solar system without having to waste as much fuel to get ourselves out of Earth’s gravitational influence.
Of course seeing this kind of technology implemented is some ways off as it seems like NASA’s next target will be a flag planting mission on Mars. Such technology would be quite applicable to Mars as well seeing as the soil there has a lot of trapped water (and there’s plentiful water ice pretty much everywhere but the equatorial region) but it’d be far more valuable if it was implemented on the moon. In either case I believe this is foundational technology that will be pivotal in humanity pushing itself to the far reaches of our own solar system and, maybe one day, beyond.
Mars doesn’t have much of an atmosphere and the little it does have is rather hostile to life, being composed almost entirely of carbon dioxide with only small percentages of other gasses detectable. Due to the freezing temperatures that grip it constantly -60°C in summer and -125°C in winter a lot of this carbon dioxide ends up in its solid form, usually buried in the permafrost. Last year NASA even confirmed that Mars experiences dry snow a phenomena where frozen carbon dioxide falls to the surface in the form of snow not unlike the water based version we have on Earth. These are all mightily cool in their own regard but there was one particular interaction that came to my attention recently that’s just so much cooler because I realized I had first seen it for myself in my backyard.
I had heard about these gullies before and had always wondered how the heck they formed. It’s not like Mars is a completely dead planet, we’ve caught crazy things like avalanches happening on it, but things that look like they require surface water (or some other liquid) in order to create them are usually out of the question (at least for new features anyway). They’re even reminiscent of the sailing stones in Death Valley, although we’ve probably solved that mystery, but the lack of something at the end of them was the thing that was really puzzling.
Where I saw this in my backyard was a chance encounter with a couple blocks of dry ice that came with a delivery of frozen meals. They weren’t as big as the blocks in the movie above, although you can get them pretty easily if you know where to look, but of course the science nerd in my wife and I couldn’t resist playing with them in the kid pool we had set up. The result wasn’t exactly surprising since we’ve all seen this kind of stuff before but it was rather interesting to see the same principles at work on Earth just as they are on Mars.
The effect isn’t nearly as dramatic but you can definitely see the same carbon dioxide cushion at work which makes the block appear to glide on the surface rather than bobbing in it like water ice does. Another cool thing (which I didn’t show in the video) is when it’s placed just below the surface that same cushion will actually propel it straight to the bottom where it will pin itself and bubble like crazy until it’s all melted away.
I’d recommend doing this for yourself as it’s one thing to see it in a video and a completely different thing altogether to play around with it. Of course there’s a whole host of other things you can do, some which I’d probably not recommend (anything that involves a pressure vessel contains a certain amount of danger), but just watching it interact with other things is pretty satisfying.