To recall, Mars is practically similar toEarth in various numbers of ways. We both have an atmosphere, although in termsof composition, they are practically different. Our rotational speeds are practically thesame, it’s just that Mars moves 2.7% slower. So with all that’s been going on with Mars,what could probably be the most exciting news we would hear about it? New craters? Finding a sufficient atmosphere? Well, how about finding something that wouldindicate the possibility of life existing at some point? Does that do anything for ‘ya? I’m sure it does! But before you go hiding underground intoyour bunkers and go panic buying for supplies and weapons to prepare for an impending invasion,I’m obliged to calm you down and tell you that “No, we won’t see those aliens withpopped eyes and huge brains with no skulls, or even some species of E.T. from Mars anytimesoon.” I know, that’s quite a bummer but I promiseyou this story will be interesting.
The news of finding evidence of life possibilityof Mars isn’t entirely something new. In 1996, the then US President Bill Clintonpresented to the press a sample from Antarctica discovered by Alan Hills in 1984. The rock named ALH84001 debris was suspectedto have ejected from Mars, and what’s special about it was that it contained traces of fossilsof what appear to be microbes! Sadly, at that conference, the press wasn’tinterested and Clinton was asked a more trivial question such as where did he get his tie. Plebs, am I right? Our planet has been sending expeditions tostudy Mars ever since 2001.
In fact, the whole world mourned when theOpportunity rover sent its last transmission back in 2018 after covering almost 45 kilometersand discovering a lot of useful information, one of which is the discovery of traces ofwater activity on Mars. However, there are still a lot of expeditionson the Red Planet working just as hard as our Oppy. For instance, in 2012, the Curiosity roverlanded on Mars with a specific goal in mind -- or it’s programming rather. The rover landed on the Gale Crater, a landdepression spanning about 154 kilometers in diameter. What’s special about this is that astronomersstrongly suspect that this crater might have been a dried up lake, since there were indicatorsthere of ancient water activity, and as we know from biology, when there’s water, there’sprobably life. This is exactly what Curiosity’s missionwas: to perform some scraping and some small digging on the soil at Gale and hopefullyfind something there that would indicate life or the possibility of it. And in 2018, Curiosity transmitted promisingresults. What it found is one key factor in determininglife, organic molecules. So, let’s explore a bit about organic matter,in case the previous sentence didn’t really do anything for you. When we say something is ‘organic’, whatit simply means is that it is related to something living or to life.
In a more technical sense, organic moleculesare compounds paired with carbon to form a new one. So what’s so special about carbon? Well, all life here on Earth, more specifically,life as we humans understand it, is a result of carbon compounds combining to more complexforms. Specifically speaking, when something is alive,it is made up of carbon compounds and quite expectedly, it is bound to emit or releasecarbon compounds. Can you put things together at this point? I bet you already can, but in case you stillhaven’t, the organic molecules found on Mars signify the presence of life at somepoint in its history. And let’s stress that word out for a bit,shall we? Take note that we used the word “signify”. We want to be careful as to not get the hypeextremely above our heads and out of control. What the findings indicate are simply a possibility,although it doesn’t necessarily verify life, but still a possibility. Of course there is more to add to this lateron, but at least for the moment, let’s take it one step at a time. So, we found organic compounds on Mars, butit doesn’t necessarily imply that there was or there currently is life on it. I mean, organic molecule production is notan exclusive process, there are other means to make this besides having them emitted byliving things. They can also be made through energy fromlight and heat, to name a few. One key compound that astronomers have discoveredthat might indicate life on Mars was the presence of methane in the atmosphere. Now, this isn’t new as ESA’s Mars Expressorbiter first verified this back in 2004, but of course that only set the gears turningon the interest about it. In fact, Mars’ atmosphere was detected tohave 60 ppbv or parts per billion volume. What Curiosity discovered was the amount ofmethane in the vicinity of the Gale Crater varies in a seasonal manner. Specifically speaking, the rover detects thehighest levels of the gas at summer phases, while it detects the lowest at winter time.
This indicates that there is some kind ofactivity under the crater that causes it to freeze in winter and melt and evaporate insummer. Does this mean there is life underneath thecrater? Well, not exactly. As we have mentioned earlier, organic moleculeproduction can occur even without the help of biological life. However, the point of controversy here isthat the amount of methane measured somehow appears to replenish itself. How do we know it gets replenished? Well, the nature of methane, and of courseall things, doesn’t really make it permanent. In fact, the light rays from the Sun willeventually break down molecules of methane after several hundreds of years, and, thisis not the case for Mars. If there are tiny Martians watching this rightnow from under the surface of Gale, we would love to hear from you. Send us a sign that you’re there! Another thing to consider is if the amountof methane in the crater wasn’t caused by biological processes, it could, on the otherhand, indicate extraordinary geological processes going on from the planetary interior, whichis equally as interesting as finding life because it will lead us to more informationabout the Red Planet. This is exactly the mission of NASA’s InSightLander, which landed on Mars in November 2018, which can dig up to 5 meters to test for geologicalactivity. I know we’ve come a long way in the story,but the tale of finding organic molecules didn’t end with methane. Curiosity also found organic molecules thatare more complex than methane. Upon digging the Gale Crater, the rover stumbledto mudstones that might have been billions of years old. These rocks are sedimentary and are most commonlyfound submerged in bodies of water, such as at the bottom of oceans, lake floors, lagoonsor even rivers, and most importantly, a great place to store and grow organic compounds. Remember how scientists initially thoughtthe crater used to be a lake? These rocks attest to that hypothesis. So how exactly do these mudstones become integralto finding organic molecules on Mars? The process goes like this.
One of the core functions of the Curiosityrover is to be able to dig at a certain depth and effectively take a few samples. Through the help of the rover’s very ownanalysis suite called SAM, or Sample Analysis at Mars, the samples were heated up 500 degreesCelsius, so that the organic molecules will be released in the form of gas. Sounds like an easy task, doesn’t it? Not entirely. Some large organic molecules are not thateasy to vaporize due to the presence of sulfur, and when the presence of this element makesit much harder to heat up. However, despite the challenge, the roverstill managed to isolate organic molecules from the mudstone, which included benzene,toluene, small carbon chains such as propane and butane, and most importantly, the onethat we’re gonna talk about more, thiophenes..and a few isotopes of it. So what exactly is it that makes thiophenesspecial? Before we dive more into that, let’s talka bit about thiophenes here on Earth. Here, these compounds are commonly found oncoals and oil crudes, and is most generally used for agrochemicals and pharmaceuticals. Besides the previously mentioned, thiophenescan also be found in white truffles, which is a really expensive and familiar ingredientfor those who love exquisite culinary experiences. Okay, does this mean that there are Martianmushrooms growing on the top of Gale Crater as we speak? Well, right around the time it was discovered,not entirely. See, the samples which Curiosity took camefrom a place that can really be easily tampered.
The rover can only dig up to 5 centimeters. Do you have a key for your door in your pocket? Try to bury that to the ground. That’s about the best depth it dug on. Not really that much isn’t it? The compounds that are stored at a depth thisshallow are strongly influenced by radiation from outer space, either from the Sun or fromany other sources. Add to that the various other compounds inthe mudstone that could have heavily affected the organic ones, it is possible that thethiophenes they have found might really be shredded parts of larger organic moleculesin the crater. It’s just that they haven’t dug deep enoughto be more certain about it. We can also attribute the presence of theorganic compounds to cosmological processes that happen frequently in our Solar System. For instance, asteroids or meteors could,at some point, have reached the Gale Crater, which may have been carrying organic substances,which later got embedded to the soil in the crater. As outrageous as it sounds, this is also avalid possibility. After all, this is how a huge part of thewater in our planet came here. As servants of science, we can’t just throwany possibility out of the window. We have to be open to a lot of possibilities. But all hope is not lost! Part of the InSight Lander’s mission isto lower down a heat probe into the mudstones in Gale and attempt to discover whether thelarger organic molecules where the thiophene may have came from. Moreover, at around the start of the secondhalf of 2020, Russia’s Rosalind Franklin will bring the Mars Organic Molecule Analyzer,or MOMA, for short to aid the investigation of the compounds. Besides that, a recent publication on theAstrobiology journal presented results that may increase the excitement on the searchand verification of organic molecules on Mars. According to the paper, the correlations foundin the analyses of the samples studies suggest that it might have been biological processesthat resulted in the presence of the organic compounds found on the mudstones. However, it’s still not mushrooms that mighthave done it and they’re leaning towards inferring that it might have been a resultof bacterial processes.
I guess Martian white truffle oil is stilla long, long way ahead in the future, but our astronomers are strongly motivated tofind the answers as soon as we can. Because of these results, the scientists recommendedto bring back samples specifically containing carbon and sulfur isotopes, as these are indicatorsof organisms sustaining themselves. If we can find traces of what the organismstreat as their “food”, we inch closer towards verifying the existence of life. I know some of you are bummed out to findout that we’re still far ahead towards finding life on Mars, but think of it this way. The organic compounds from the Gale Craterindicates that this place held up the necessary ingredients for life to have possibly existed. And who knows? Maybe life did exist or is currently existingon Mars, but just not in the way that we know it. If you have watched the movie Evolution backin 2001, the aliens there were nitrogen-based organisms, and it’s a strong possibilitynot just for Mars but for other places as well. As astronaut Neil Armstrong once said, “Onesmall step for man is a giant leap for mankind.” We just need to hold on there and keep exploring! To end this episode, let me pass on a questionto you, my dear viewers: assuming we have are to find life on Mars, would they be ofsimilar composition as us? Are they going to be carbon-based, or arethey going to be based on something else? Do you think we’re closer to finding extraterrestriallife? Let us know what you think! Leave your answers in the comment sectionbelow. You know, one of the pastimes I enjoy is readingwhat you wrote. I hope there’s a way to show you how gratefulwe are for viewing! If you like this episode, don’t forget topress the like button to keep us going. If you like content like these showing upon your feeds, why don’t you click on that subscribe button and the bell icon too sothat you get notified whenever something new comes up? We release new videos almost every day! See you soon! Stay insanely curious!
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