Is Life Possible on Mars?

Marrs it's been the fascination of science and science fiction for over a century a knowledge of the planet actually goes back to the ancient Sumerians more than six thousand years ago who believed the planet was Naugle the god of war and plague but it wasn't until 1610 when Galileo pointed his telescope at it that we got our first look at Mars upon viewing the planet Galileo saw a reddish orange body encapsulated on top and bottom by polar ice caps then around a hundred years after they were discovered in the 18th century William Herschel used a 20 foot long telescope to observe the polar icecaps expanding and shrinking with the changing of the Martian seasons scientists at the time thought this indicated the melting and freezing of liquid water on the surface of Mars as the planet transitioned through summer to winter this led many early astronomers to predict life to be present on the planet and soon dark spots on the surface were mistakenly identified as oceans and vegetation was assumed to be present as well then in 1877 Giovanni Schiaparelli endeavored to produce the first detailed map of the planet in doing so he observed and recorded straight lines traversing across the surface of the planet on his map he titled these lions canal I despite the direct translation of this term to mean channel or groove theories of canals dug across Mars abounded as a result these were believed to be evidence of a spectacular but endangered Martian civilization classic stories like HG Wells is the War of the Worlds and Edgar Rice Burroughs John Carter series were based on these notions of a dying Martian civilization or with better equipment these lines were shown to be an optical illusion of the telescope's used and it was more recently deduced that the expansion and reduction of the polar icecaps are the result of buildups of dry ice or solid carbon dioxide and not the melting and freezing of liquid water but after that Mars has been front and center in the discussion and in search for extraterrestrial life and to this day the question remains could there be life on Mars this video is the second in a series in which I look at the potential of other planets and moons in our solar system to harbor life my last video was about the possibility life on Saturn's largest moon Titan if you haven't already watched that video I'd highly suggest it but enough about that let's get into it like I stated in my last video the search for extraterrestrial life almost always begins with the search for liquid water so that's where we're going to begin - on the surface of Mars if there is no liquid water currently but that wasn't always the case to begin answering this question we first need to go back four billion years to a time when Mars was just an infant planet and was experiencing what's called the noachian period in Martian history because Mars was newly formed and its center was a core of molten metal with a molten core Mars had a substantial magnetic field and could protect its atmosphere and its surface from destructive solar radiation and it also hosted many bolstering volcanoes as a result Mars maintained a much higher surface temperature than it currently experiences in fact temperatures above the freezing point of water were common throughout the planet and liquid water was to be found in vast quantities at this time a giant Highland region called the Tharsis was particularly active with volcanism in total the Tharsis area covers around 30 million square kilometres or roughly 25% of the total surface of the planet and an estimated 300 million cubic kilometres of igneous rock material was exerted from this area alone three massive shield volcanoes sit in a line on top of the Tharsis region and Olympus Mons is just to the west of them these are some of the largest volcanoes in the solar system with Olympus Mons being the tallest volcano known to exist anywhere and if the magma excreted by this volcanic plane was similar in composition to the magma found on earth meaning it contained carbon dioxide and water vapor in similar proportions which evidence supports this would have led to the creation of an atmosphere one and a half times the density of Earth's and would have produced enough water vapour to cover the entire planet and 120 metres of liquid water in fact it's been estimated that during the noachian period anywhere from 36 to 75% of the surface of Mars was inundated with liquid water because of a peculiar dichotomy between the north and south hemispheres which results in elevated altitudes throughout the southern half of the planet most of the water was concentrated as a single ocean in the northern hemisphere but evidence of liquid water can also be found all over the surface of Mars and dried river channels running through tremendous canyons larger than most found on earth and sometimes ending in huge river deltas many lake beds can be found at the bottom of craters on the surface of the planet as well some of which are equivalent in size to the Caspian Sea the largest lake on earth also found on Mars from the same time our soils rich in the compound silica first discovered by the spirit rover after a malfunctioning wheel disturbed the topsoil the presence of silica in the soil suggests evidence of hot springs and other hydrothermal features on Mars and if you'll remember from my last video it was in very similar conditions here on earth that life first began with what we know about the formation of primordial life this was a highly promising environment at least capable of fostering life if not creating it but it's also important to remember that these conditions existed four billion years ago when the solar system was still new and therefore filled with plentiful amounts of debris in the form of asteroids it's been estimated that every 100 million years during the noachian period an asteroid big enough to create a 100 kilometer impact crater would collide with Mars these impacts would continually fracture Mars's crust and spread ejecta across the planet and into the atmosphere and make long-term sustained life on a planet wide basis nearly impossible but conversely a study found that inside the impact craters there could have been hydrothermal systems created by the impact with the proper conditions to encourage the formation of life for possibly millions of years after a collision and these highly active impact craters life may have formed on its own a countless number of times in the past okay so what about today could there be life on Mars now well clearly these conditions have not been preserved virtually zero volcanic activity is to be found on Mars while the atmosphere is almost entirely gone and water can only be found in the form of ice at the poles or as brine a mere five hundred million years after Mars itself was formed it died so what happened in short Mars is small compared to Earth Morse's barely half the diameter and that actually means earth is around six and a half times larger by volume than Mars is in the end it's this fact alone that doomed Mars you see with a lesser volume Mars's molten core cooled and a much faster rate than Earth's did known law of thermodynamics and while today the earth maintains an entirely liquid metal core Mars's solid almost the whole way through without firing convecting at the center of mars its magnetic field diminished and allowed ionizing particles from the Sun to rip through the atmosphere killing any potential for the formation of new life and stripping the planet of its water but life is resilient and while conditions on Mars may be exceedingly bleak life has surprisingly managed to persist in even worse places last week I showed this creature as an example of an extreme file this is a tardigrade also known as a water bear and there perhaps the toughest organism known to science they are found basically everywhere on earth including the Sahara Desert and the McMurdo Valleys in Antarctica which are considered to be some of the driest and coldest places on earth but more importantly in 2007 a team of European researchers sent a population of tardigrades into orbit around Earth for ten days during this time the tardigrades were exposed to the near-perfect vacuum of space and were completely unprotected from damaging radiation given off by the Sun upon returning to Earth the researchers found 68 percent of the tardigrades were still alive and their ability to survive even in the deleterious environment of space has given those seeking life on the dead world of Mars hope for a similarly enduring creature to make matters more interesting part of grades are actually aquatic creatures and can only thrive when water is present in their environment this may in fact explain how tardigrades managed to survive in space - you see when water dries up in their environment they begin a process known as desiccation meaning they shrivel up lose 97% of their body's water content and slow down their metabolism to an astonishing 0.01 percent of its typical rate after this they wait it could be weeks months even years before water returns with some tardigrades capable of lasting more than a decade in this state but then all it takes is a few drops of water to bring them back to normal after this a resilience to extreme heat having survived at temperatures above 150 degrees Celsius and temperatures below negative 270 two degrees Celsius that number is exceeding the impressive knowing that negative 273 degrees Celsius is equivalent to zero degrees Kelvin the theoretical low with temperature possible in physics at this temperature atoms themselves would be frozen still tardigrades miraculously also produce what amounts to a shielding of antioxidants which guard it from damaging solar radiation not found on the surface of Earth but which pose possibly the greatest threat to life on Mars when combined these factors produce an organism that potentially could exist somewhere beneath the surface of Mars in a dormant state waiting for the return of liquid water and in 2015 NASA confirmed that liquid water is still present on the surface of Mars and in reoccurring slope lineae at least occasionally when seasonality czar at their greatest they can be seen as the darker areas flowing downhill in these images with all this information there's been a great deal of speculation around the possibility of organisms left over from Mars as infantile days which could have evolved during times of perpetual environmental disturbances such as the constant bombardment from asteroids which caused them to be adaptable to a wide variety of climate conditions and have persisted beneath the surface of the planet laying dormant until seasonal waters return while this theoretical model sounds fairly promising I should remind you again no definitive evidence has been found on Mars that indicates that there was ever life here so now let's take a look at some of the challenges towards life on Mars as I mentioned before harmful ionizing radiation given off by the Sun floods the surface of the planet due to the weak magnetic field and thin atmosphere this alone rules out any potential for life on the surface of Mars as this type of radiation has the power to break carbon bonds effectively tearing apart molecules and tissues necessary for life but below the surface dirt and rock can't protect against these damaging rays and perhaps like the soil on earth which is brimming with microscopic populations deep within the Martian soils when some life may reside and despite having confirmed evidence of liquid water it's not the same type of store-brand water you might be thinking of temperatures on Mars even during the warmest parts of the Martian summer don't reach above 0 degrees Celsius the temperature required to melt ice instead salts present on and beneath the surface of Mars like magnesium perchlorate sodium perchlorate and magnesium chloride have dissolved into the water and therefore lowered the freezing temperature of it like how on earth road salt slower the freezing temperature of ice and snow being well below freezing and in high concentrations of salts would definitely serve as an obstacle for continual habitation to make matters worse that many of these salts are in the perchlorate family which are for the most part incredibly toxic to any living thing here on earth furthermore other compounds present in the soil like iron oxides which give the soil its reddish coloring and hydrogen peroxide act in tandem with the perchlorates to create a soil environment detrimental to cells and unlike ionizing radiation which can't penetrate more than a few metres below the soil for chlorates and other compounds are prevalent throughout the soil layers and are present across the planet because of this most of Mars has been deemed uninhabitable but a total of around 40 different organisms are known to exist on earth that are actually capable of using perchlorate as a means of deriving energy through a complex perchlorate reduction reaction which is important too because again due to the ionizing radiation organisms would need to bury themselves deep beneath the surface and would not be able to use the Sun as a means of deriving energy another issue is the lack of nitrogen on Mars on earth nitrogen makes up 78% of our atmosphere and all life requires some degree of available nitrogen in the environment while this type of nitrogen is inert certain organisms like legumes are capable of making usable compounds such as nitrates with it that then spread throughout an environment this is called nitrogen fixation unfortunately on Mars the nitrogen levels in the atmosphere aren't high enough to support any means of nitrogen fixation however in 2015 the Curiosity rover discovered the product of nitrates in the soil in the form of nitric oxides which results from the heating up of nitrates reminiscent of a time earlier in Mars history when nitrogen fixation into nitrate could have been possible the last issue is the low pressure created by Mars as thin atmosphere at pressures this low most terrestrial cells would burst wide open but the atmosphere took time to diminish into this state and it's possible in theory for organisms to have evolved alongside this change to withstand such low pressures okay so life on Mars seems pretty tough and unforgiving but at this point not impossible and a lot hinges on whether or not life ever did develop on Mars in the past as life would likely not develop under current Martian conditions but in the immortal words of Ian Malcolm life finds away so lastly let's take a look at any potential evidence that we've found that directly involves life on Mars frustratingly the Mars rovers aren't really designed to look for life on Mars but rather to look for the conditions which would make Mars suitable for life so despite having research equipment on Mars our best bet for finding evidence of prehistoric Martian life is to be found on earth in the form of meteorites we have found several meteorites which began their life on Mars but which found their way to earth as the result of an asteroid impacting the surface of Mars millions of years ago the neckla meteorite for example was recovered from neckla egypt where it fell in 1911 and was examined by NASA in 1998 analysis of the neckla meteorite found grooves and indentations in the rock which predate its time on earth that roughly matched the size and shape of certain terrestrial nano bacterial fossils also found were potential fossils of organisms in these doughnut-shaped markings but it's difficult to say with certainty what exactly caused them other anomalies found in the neckla meteorite include high quantities of organic matter amino acids and dendritic carbon which all point to the possibility of ancient Martian life another meteorite the Yamato zero-zero-zero 539 was formed as part of a lava flow on Mars only 1.3 billion years ago and landed in Antarctica 50 thousand years ago after cutting into it unusual microscopic spheres rich in carbon were found inside the rock no explanation has been given as to what caused these spheres to form and even some NASA scientists have speculated that these may be the signs of biotic activity from Mars's past another sign of potential life on Mars comes from the atmospheric analysis of methane on Mars methane exists in trace amounts within the Martian atmosphere which is important because methane is an unstable molecule and given a little time it will break down into formaldehyde and methanol what this means is that for methane to be found on Mars something must be producing it currently on earth methane is one of the main byproducts of of cellular respiration and this has led many to speculate that there is a culture of methanogenic microorganisms like the one I described in my last video producing this methane methane or genic life is purely theoretical but still possible and simulations suggest that this type of life could survive in an environment rich in perchlorates whether any of this evidence indicates life on Mars either in the past or even the present is still uncertain but I would say at the very least life was once possible on Mars billions of years ago to determine if Mars remains a living planet we'll need to send more Rovers to Mars especially ones capable of digging down into the deep soil layers where shelter from damaging radiation is to be found I hope you liked this video and if you did please consider subscribing to this channel or even just liking this video there will be more videos like this coming soon if you have any comments or suggestions or things I missed in this video please let me know in the comments below thanks

Channel: Atlas Pro

Views: 666,993

Rating: 4.9057455 out of 5

Keywords: space, spaceX, mars, martian, martian life, life, life on mars, life mars, mars life, space exploration, Earth, NASA, Curiosity, Curiosity rover, Spirit rover, War of the Worlds, John Carter, Alien, Alien life, Extraterrestrial life, Extraterrestrial

Id: Qma9l3-MryY

Length: 16min 15sec (975 seconds)

Published: Wed Apr 11 2018

Reddit Comments

[u/[deleted]]

The video is nice, but it's clearly just a smattering of information from 'popular scienec' sources.

It get's a lot of basic science wrong (in exactly the way a lot of news articles have presented things). For example, tardigrades aren't the magic monsters many articles make them out to be, and while Mars did cool down faster due to its size, this isn't strictly due to thermodynamics. Even the Earth would've cooled down by now if thermodynamics was the only consideration. Subsurface radioactivity is the more significant factor. Relatedly, the lack of a planetary magnetic field isn't what stripped Mars of its atmosphere. This has been disproven by multiple lines of evidence, and the persistence of this false factoid is starting to drive me nuts. While solar winds do carry away gasses from the upper Martian atmosphere, they also induce a magnetic field in the upper atmosphere. When the solar winds increase in intensity, so to does the induced field (and its protective effect). As a result, the volume of gasses lost don't actually increase much with solar wind intensity, what does increase is the speed at which they're blown away from Mars. What actually accounts for most of Mars' losses is photoionization. Ultraviolet light (specifically the higher frequency portion of it) has the requisite energy to break (ionize) many compounds. The lighter products which can result from this often have an easier time rising through the atmosphere, making them more likely to be blown away by solar winds. So, while solar intensity does increase atmospheric loss, the wind vs the magnet field isn't the dominant dynamic. This distinction is important because if photoionization is the problem, then the real issue is the lack of an ozone layer. It's also worth noting that this doesn't mean the small size of Mars hasn't played a (different) role in the planet not having much of an atmosphere. The smaller size, which led to more rapid cooling, which led to decreased geological (areological) activity, didn't just cause the internal magnetic field to shut down. It decreased the amount of gasses being released into the atmosphere from the ground. So again, while the lack of an internal magnetic field didn't directly cause the thin atmosphere, they are related.

As a sanity check for those who don't know much about the principles I just referred to, think about Venus. It doesn't have an internal magnetic field, and it's closer to the Sun than Mars, yet it still has an extremely thick atmosphere.

I suppose this, strictly, doesn't matter if you just want to know if life could've existed on Mars. For that, you just need to know if the conditions were right. But, if you want to explain those conditions with facts about the planet, please get them right. The propagation of false information isn't helpful.