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.
Looking at the ingredients labels on food can be both an insightful and frightening affair. I’ve long been in a habit of doing it and I always find it fun to research some of the more esoteric ingredients, well that is right up until I find out where some of them come from. It’s the old adage of not finding out how the sausage is made, although in reality you should probably consider that with all things that you put in your body. Still when I watched the following video I was honestly surprised to see the outcome, as I didn’t think the effect of extracting iron from cereal would be so dramatic:
The first half of the video explores the idea that there’s elemental iron within cereal which can then be attracted by a magnet. Whilst this is true to some degree, the iron within the cereal will feel an attraction to a magnet, you can actually perform the exact same experiment with cereal that is bereft of any elemental iron content. This is because water is a diamagnetic material which is a fancy way of saying that in response to a magnetic field it will create its own inverse field in response. For the cereal and magnet experiment this means the water actually divots around the magnetic field which the piece of cereal then falls into. The iron in the cereal helps this process along of course, but it’s not the only force at play here.
However the extraction of the iron from the cereal was pretty astonishing, especially considering just how simple it was to do. Trying to extract other elements from the cereal would prove a much harder endeavour which is why I think an experiment like this is such a powerful visual aid. You’re literally seeing the iron being pulled from the food you eat which, in turn, makes you think about all the other things that are listed on the ingredients label. It might not be a particularly pretty picture that you end up with, but at least you’ll be far more aware.
I wish I knew about these kinds of science experiments when I was a kid!
As I hope is blatantly obvious by now I’m very much a fan of the sci-fi genre. It started out as a fascination with the future, with all the tech wizardry that it promises us, however it’s long since grown into a full fascination with the world of science and what plausible futures could arise from it. Thus, whilst I enjoy a good story in its own right, sci-fi movies and other media are a great opportunity to explore scientific principles and I love to see how they’re used as plot devices. Of course the narrative will often take precedence over the laws of the universe and whilst I can appreciate a departure for the sake of plot I have my limits, like Gravity’s take on how orbital mechanics work. However there’s been quite the hubbub around the science behind Interstellar and I finally managed to catch it over the weekend.
In terms of basic science Interstellar gets top marks for getting so many things right. Things like travel time between planets in the solar system, gravitational lensing of light around objects that have heavy gravity or spacetime warping properties and the handling of relativity all line up with my (admittedly limited but I’d hazard a guess better than average) understanding of how those principles work. The black hole itself was absolutely stunning with the interaction of the accretion disc with the strong gravitational lensing, something which now seems so obvious, giving us a new perspective on what these monsters would actually look like out in space.
The robots are also one of my favourite aspects of Interstellar as they go from being what appears to be some kind of clunky, cumbersome relic of the pre-blight era they’re in fact highly capable machines. The designs are incredibly interesting too as whilst many movies would’ve gone for the stereotypical humanoid Interstellar instead opts for a HAL-9000esque monolith. It’s hard to discount that their personalities play a big part in this too, especially with all the humour around their programmable emotional settings.
PLOT SPOILERS BELOW
There are numerous liberties taken with certain mechanics however, all which are somewhat forgivable since they’re in aid of the plot. The small craft which are quite capable of achieving orbital velocities would have to have some kind of advanced engine that doesn’t rely on propellant and has the required thrust and specific impulse to achieve such feats. This is somewhat hinted at the start when the craft they use to get to Saturn makes it there in 2 years (I’d assume without any gravitational assists) however it’s still something that bears mentioning. It’s mostly only because if they had technology like that then it’d be quite easy to get a lot of people into space, potentially making that habitat they were working on viable without needing the secret “gravity” source.
As with all movies that like to play around with the notion of time things start to get a little hand-wavy once you start mucking with the timelines. Once Cooper’s character is stuck in the tesseract he’s essentially creating a paradox since he wouldn’t be there without the manipulations he caused, yet he is already aware of them when he’s making them. The one way to rationalize this away is to eliminate the prospect of free will within that world and so Cooper was compelled to do that no matter what happened. Otherwise he could, say, send the quantum data to someone else through another method, rendering the whole mission moot (but then introducing yet another) paradox to contend with. Indeed whilst this later part of the movie is a great piece of cinema it’s riddled with scientific problems, one that likely needs a novel to explain them away.
One thing that does irritate me about films of this nature is that they usually follow the format of “everythings going ok for a bit until things go all Event Horizon on you”. I get that this is playing into the fragility of the human condition, where our survival instinct makes us do things we otherwise wouldn’t, however it does feel like the trope has been done to death. There’s multitudes of other avenues to pursue to provide that kind of tension without relying on humans going postal, but it seems human fallibility is still the route of choice. Then again hard sci-fi is a hard sell without a relatable human element, which I guess is the reason we keep seeing it.
PLOT SPOILERS OVER
All in all I thoroughly enjoyed Interstellar despite the last sections wandering into extreme hand-waving territory. The scientific basis which it begins from flows through the entire movie, providing a great backdrop for the rest of the movie to build on. I’m looking forward to seeing a breakdown of how all of the strictly-not-scientific elements were developed as there’s a lot of questions I’d like to see answers to. In the same vein though I’m also completely ok not knowing as the discussion my wife and I had afterwards were just as interesting as watching the movie itself. Definitely a must see for all sci-fi fans out there.
I’ve never really been one for trains, neither those that serve as public transport or their diminutive brethren that grace the basements of many, but the technology behind some of them is quite impressive. Indeed you can’t go past the Shinkansen of Japan, trains that are so fast that they regularly compete with airlines for the same passengers and have recently achieved astonishing speeds. However beneath all the technical wizardry that powers those impressive machines lies some incredibly simple physical principles, ones that can be replicated with some copper wire, a couple magnets and a battery:
The way it works is incredibly simple. The “car” of the train is made up of a couple high-strength magnets that are oriented in the same direction, ensuring that their magnetic fields flow in the same direction. Then when the car is placed onto the track of coiled wire they help complete a circuit with the coil of wire around it. This then creates a magnetic field around the car and the resultant force between it and the permanent magnets results in a force that’s vectored forward. However the time it will be able to do this is limited however as the creation of the magnetic field consumes power from the battery. Most estimates online have the run time somewhere around 30 minutes or so from a typical alkaline AA battery.
Indeed one interesting thing about this train is that it relies on the high internal resistance of regular alkaline batteries to function properly. You see a typical battery has what amounts to a current limiter inside it, preventing anything from drawing current too fast from it. If they used say a NiCd style battery, which has an incredibly low internal resistance, I can see the results being either much more spectacular (like the car flying around the track) or catastrophic (like the battery overheating and the wire melting). Actually now I’m kinda curious about what would actually happen.
Now where’s that old battery charger of mine…
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.
One 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.
There are some things you just don’t think about until they’re shown to you. Most people don’t think twice about why the same side of the moon always faces us, it’s either just coincidence or divine intervention, but when you learn it’s a relatively simple aspect of gravity (tidal locking) you find yourself asking where else such things might occur. Likewise I had never really thought about why rivers tend to twist and turn, thinking that it was most likely because there were things in the water’s way that it was just getting around, but as it turns out there’s a very clear explanation for why they bend, even without objects being in their way:
Understanding these fundamental principles is what allows us to look at other places in the universe and draw conclusions about what they might have been like billions of years in the past. We’ve long speculated that Mars was once host to oceans and rivers not unlike our own based on ideas like this; their snake like remnants still being visible long after the water has departed. Hopefully one day we’ll find the ever elusive underground reservoirs of water on Mars and maybe, just maybe, find evidence of life that may have once played a role in shaping those long forgotten rivers.
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.
For much of my childhood people told me I was smart. Things that frustrated other kids, like maths, seemed to come easy to me and this led to many people praising my ability. I never felt particularly smart, I mean there were dozens of other kids who were far more talented than I was, but at that age it’s hard to deny the opinions of adults, especially the ones who raised you. This led to an unfortunate misconception that stayed with me until after I left university: the idea that my abilities were fixed and that anything I found hard or difficult was simply beyond my ability. It’s only been since then, some 8 years or so, that I learnt that any skill or problem is within my capability, should I be willing to put the effort in.
It’s a theme that will likely echo among many of my generation as we grew up with parents who were told that positive reinforcement was the way to make your child succeed in the world. It’s only now, after decades of positive reinforcement failing to produce the outcomes it decried, we’re beginning to realise the folly of our ways. Much of the criticism of our generation focuses on this aspect, that we’re too spoilt, too demanding when compared to previous generations. If there’s one good thing to come out of this however it’s that research has shown that the praising a child’s ability isn’t the way to go, you should praise them for the process they go through.
Indeed once I realised that things like skills, abilities and intelligence were primarily a function of the effort and process you went through to develop them I was suddenly greeted with a world of achievable goals rather than roadblocks. At the same time I grew to appreciate those at the peak of their abilities as I knew the amount of effort they had put in to develop those skills which allowed them to excel. Previously I would have simply dismissed them as being lucky, winning the genetic lottery that gave them all the tools they needed to excel in their field whilst I languished in the background.
It’s not a silver bullet however as the research shows the same issues with positive reinforcement arise if process praise is given too often. The nuances are also unknown at this point, like how often you should give praise and in what fashion, but these research does show that giving process praise in moderation has long lasting benefits. I’d be interested to see how well this translates into adults as well since my experience has been vastly positive once I made the link between effort and results. I can’t see it holding true for everyone, as most things don’t in this regard, but if it generally holds then I can definitely see a ton of benefits from it being implemented.
Time is a strange beast. As far as we know it always appears to go forward although strange things start to occur in the presence of gravity. Indeed if you synchronized two atomic clocks together then took one of them on a trip around the world with you by the time you got back they’d be wildly out of sync, more than they ever could be through normal drift. This is part of Einstein’s theory of general relativity where time appears to speed up or slow down due to the differing effects of gravity on the two objects which results in time dilation. This effect, whilst so vanishingly small as to be inconsequential in day to day life, becomes a real problem when you want to tell super accurate time, to the point where a new atomic clock might be worthless for telling the time.
Most atomic clocks in the world use a caesium atom to tell time as they transition between two states with an exact and measurable frequency. This allows them to keep time with incredible precision, to the point of not losing even a second of time over the course of hundreds of millions of years. Such accurate time keeping is what has allowed us to develop things like GPS where accurate time keeping allows us to pinpoint locations with amazing accuracy (well, when it’s not fuzzed). However a new type of atomic clock takes accuracy to a whole new level, being able to keep time on the scale of billions of years with pinpoint precision.
The Strontium Optical Atomic Clock comes from researchers working at the University of Colorado and can hold perfect time for 5 billion years. It works by suspending strontium atoms in a framework of lasers and then giving them a slight jolt, sending the atoms oscillating at a highly predictable rate. This allows the researchers to keep time to an incredibly precise level, so precise in fact that minor perturbations in gravity fields have a profound impact on how fast it ticks. As it turns out Earth is somewhat of a gravitational minefield thanks to the tectonic plates under its surface.
You see the further away you are from the Earth’s core the weaker its gravitational pull is and thus time passes just a little bit faster the further away you get. For us humans the difference is imperceptible, fractions of a fraction second that would barely register even if you found yourself floating billions of kilometres away in almost true 0g. However for a time instrument as sensitive as the one the researchers created minor changes in the Earth’s makeup greatly influence its tick rate, making accurate time keeping an incredibly difficult job. Indeed the researchers say that these clocks are likely to only be able to truly useful once we put one in space, far beyond the heavy gravitic influences that are found here on Earth.
It’s amazing that we have the ability to create something like this which throws all our understanding and perceptions around such a common and supposedly well understood phenomenon into question. That, for me, is the true heart of science, uncovering just how much we don’t know about something and then hunting down answers wherever they may lie. Sure, often we’ll end up having more questions when we come out of the end of it but that’s just a function of the vastness of the universe we live in, one that’s filled with ceaseless wonders that we’re yet to discover.