Posts Tagged‘water’

Enceladus Cassini

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.

Pouring water into glass

No, Fluoride Isn’t Making You Stupid.

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.

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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.

Shitty Telstra Copper Pit

The Problems a FTTN NBN Won’t Fix.

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.

Shitty Telstra Copper PitMy 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.

 

india-chandrayaan-1-spacecraft

What Water On The Moon Means For Space Exploration.

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.

india-chandrayaan-1-spacecraftThe 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.

 

Water From Air.

We all know of the moisture contained within air, commonly referred to as humidity. Where I am it’s typically on the low side which has its advantages (evaporative cooling works a treat here) although it does tend to make any winter cold feel like it’s a frozen knife cutting through your very being. High humidity on the other hand gives rise to some potential applications that you might not have considered before like being able to extract drinkable water directly from the air that surrounds you:

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What’s interesting about this particular idea is that it’s actually been around for quite some time in the form of consumer level devices. I remembered reading about them being available in Japan almost a decade ago and whilst the scale of the billboard vastly surpasses those little water coolers the technology that drives them is essentially the same.

Indeed the technology is so mature that NASA makes use of a very similar system to extract water from the atmosphere contained within the International Space Station which was installed during STS-126. Theirs also has the awesome (although some may say disgusting) ability to process urine back into potable water which allowed the ISS to expand its total crew from 3 to 6. Due to the shuttle’s retirement though such crew levels haven’t been sustained for a while although that could change in the near future.

Isn’t it fascinating to see how far and wide technology like this spreads?

Dry Ice on Mars (and Earth).

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.

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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.

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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.

Ice Crystal Formation on a Soap Bubble.

Thanks to our northern hemisphere counter-parts I’ve been privy to all sorts of interesting cold weather things from making instant snow to the ingenuity that people come up with when they’re snowed in. Here in Australia we do get the up on the other end of the spectrum quite often during summer however although that doesn’t really drive us to do much more than sit around a pool and drink copious amounts of beer. So you can imagine then that anything involving sub-zero temperatures is going to be somewhat intriguing to us, especially something as cool as this:

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There’s nothing particularly complicated about what’s going on here but the demonstration is quite novel. What you’re seeing is the formation of ice crystals on the surface of a soap bubble which starts off slow but ramps up significantly as more crystals form. I think this is partially due to the way crystals form as they usually need a rough surface to attach to. This is how those instant ice videos work as the bottles don’t have any anchor points for the crystals to form but once you shake it up a bit you give them a surface to attach to.

There was one question that was left unanswered due to the video cutting off at the end however: whether or not it’d still float after it was frozen.

Now the bubble isn’t increasing in mass, it’s simply changing forms. There’s the possibility that some of the moisture from the air outside the bubble will condense onto the crystalline surface however I don’t think that’d change the mass by an appreciable amount. The density would also be going down as well thanks to water’s intriguing property of getting less dense as changes into ice. All those factors together would indicate that a frozen soap bubble would behave in much the same way as a regular one but I’d still like to see this hypothesis tested.

Although I do much prefer warmer climates, so this will have to be an exercise that’s left up to the reader.

Red Hot Metal And Water – The Reaction Isn’t What You’d Expect.

There’s a really interesting experiment you can do in the comfort of your own home that demonstrates an effect I’m about to show you. All you need is a frying pan and some water. Heat up the frying pan until its good and hot and then flick droplets of water onto the pan. Curiously the droplets won’t instantly burst into little puffs of steam, instead they’ll skitter around on the surface of the pan in apparent defiance of the blazing surface that’s underneath it. This effect happens when any kind of liquid comes into contact with a surface past a certain temperature but I hadn’t really considered what would happen if you put the surface in the liquid:

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The phenomenon at work here is called the Leidenfrost Effect. It’s a pretty cool reaction whereby an initial layer of vapour formed by a liquid hitting a sufficiently hot surface forms a protective barrier which is what allows those water droplets I described earlier to skitter around rather than turning into steam. It’s clearly visible in the video at the start where a pocket of water vapour forms around the outside of the red hot sphere. It eventually collapses as the vapour isn’t a perfect insulator but it does manage to stay quite hot for a lot longer than you’d expect.

One thing I can’t figure out a good explanation for those is the incredible sounds that are produced. The rapid generation of steam could possibly explain part of it as some of the sounds are similar to what you hear from say a steam wand on a coffee machine but most of them have a definite metallic twang to them. It’s quite possible that all of the noises are coming from the ball itself as it cools down much like some cars which make a distinct “tink” noise when turned off (the noise comes from the exhaust pipe cooling down). I wasn’t able to track down a name or reliable explanation for this effect however so if you’ve got one I’m all ears ;)

Fun With Hydrophobic Sand.

There’s been something of an explosion of hydrophobic (something that’s literally water proof) products recently. Many of the products are pretty novel ideas that have practical applications like shoes and boots but there are many other, stranger devices like this device that can pick up condiments spilled on a table. I thought I had seen most of the cool applications of hydrophobic coatings already until I came across this little gem the other day and the science behind what you see in it is quite awesome.

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So this sand, called Magic Sand which you can buy or even make yourself, starts to act in a rather odd way once it gets under water. You’ll notice that it sometimes takes a bit of effort to actually get it under the water and that’s because, just like oil, it would prefer to float on top of it rather than mix with it. Once its under there however it seems to stop acting like a power and starts acting like a semi-solid, being quite malleable. Once you take it out of the water however it returns to its former powder state, losing any of the properties it just had.

The reason for this is pretty simple and would have some pretty cool effects if they had a deeper tank or a pressurized container. Once the power is under water its put under pressure by all the water molecules around it, much like SCUBA divers are. This forces it to clump together which is what gives the sand its apparently malleability. Once its removed from the water this pressure is gone and we’re left with the powder we had before hand. If you had a really deep tank and did the same experiment the sand would become less and less malleable as the depth increased as the pressure exerted on it would continue to go up. Dropping some of this into the Mariana Trench would likely give you a hydrophobic rock by the time it reached the bottom, and an incredibly dense one at that.

The sand also has a practical purpose other than being a cool science based toy. Originally it was developed as a solution for surface oil spills where you’d cover the spill with the dust which would then be heavy enough to sink allowing for recovery. That method is unfortunately too expensive to be used and most clean ups instead rely on booms and specially designed ships but it is being tested for other applications.

Man if my younger self could see me now. He’d be wondering why the hell a grown man was so interested in all these boring, educational things. I seriously can’t get enough of them now :D

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.