21 votes Radar evidence of subglacial liquid water on Mars Posted July 25, 2018 by Diet_Coke http://science.sciencemag.org/content/early/2018/07/24/science.aar7268 13 comments Collapse replies Expand all Comments sorted by most votes newest first order posted relevance OK −  Diet_Coke (OP) July 25, 2018 (edited July 26, 2018) Link edit: If you want something a little less science-y and more accessible, here is a NYT article on the same thing Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars. edit: If you want something a little less science-y and more accessible, here is a NYT article on the same thing 3 votes −  TreeBone July 26, 2018 Link Parent This all is too confusing for me except the last line. What does this mean for the future in terms of Mars exploration or just in general? This all is too confusing for me except the last line. What does this mean for the future in terms of Mars exploration or just in general? −  Diet_Coke (OP) July 26, 2018 Link Parent It's possible that there is life there, as a stable body of water could host the type of extremophile life that we see in some environments on Earth. It's possible that there is life there, as a stable body of water could host the type of extremophile life that we see in some environments on Earth. 3 votes −  Amarok July 26, 2018 Link Parent At this point I think it's guaranteed we'll find life there - nothing fancy, just some very hardy, tiny extremophiles. Frankly, Mars is just too damn close to Earth. Something has to have drifted... At this point I think it's guaranteed we'll find life there - nothing fancy, just some very hardy, tiny extremophiles. Frankly, Mars is just too damn close to Earth. Something has to have drifted between them at some point over the last four billion years. Those martian summertime methane spikes are very suspicious. Life in the general sense is damn near indestructible once it gains a foothold. Finding that life isn't the interesting part. Finding out if it's got RNA/DNA and gene sequencing it to find out if we share a common ancestor is the interesting part. Then we get to ask the question... did it start first on Mars, or first on Earth, or did they start at around the same time - and if they did, where did the initial seed come from? If we find out it has nothing in common with us, things get wildly interesting... 3 votes −  CALICO July 26, 2018 Link Parent While any and all scenarios involving extraterrestrial life are wildly exciting, the RNA/DNA bit is what I'm really excited to find out. If we can confirm there is life on Mars, and it encodes... While any and all scenarios involving extraterrestrial life are wildly exciting, the RNA/DNA bit is what I'm really excited to find out. If we can confirm there is life on Mars, and it encodes genetic information the same way as terrestrial life, but evolved entirely separately, the ramifications of that would be staggering. Today, nucleic acid polymers are the basis for all known life. One of the biggest questions is not so much whether the is life somewhere out there, but rather 'what does it look like, and how does it function?' Is our model just one of many ways that life can occur, or is that just how life works in our Universe? If Martian organisms are confirmed to exist, have nucleic acid polymers, and not share a common ancestor with terrestrial life, that would be massive! 1 vote −  Amarok July 26, 2018 (edited July 26, 2018) Link Parent Beyond massive, really. It'd mean life goes from being a rare or singular event to being business as usual anywhere liquid water is present to facilitate fancy chemistry. That would mean that we... Beyond massive, really. It'd mean life goes from being a rare or singular event to being business as usual anywhere liquid water is present to facilitate fancy chemistry. That would mean that we could reasonably expect to find life on nearly every planet that was in a Goldilocks zone like Earth and Mars are. That's the sort of explosive element that kicks the Drake equation into overdrive. Kepler's found what, more than a thousand planets like that already, using our admittedly primitive detection methods? I can't wait for Webb to come online. Doesn't solve the Fermi paradox, though. If life is that common, why isn't there more evidence of intelligent life? Which filter did we pass that almost no one else does, and which filters are still waiting for us? Finding the most basic microbes on Mars is worrying. Finding complex multi-cell life is bad news. Finding post-Cambrian level plant and animal fossils is stunningly bad news. Finding any evidence of evolved intelligence, such as ancient writings, would be catastrophically bad news and spell almost certain doom for life on Earth. Fermi was a rat-bastard, wasn't he? Just working through the implications is rather staggering and will take decades. I want to see it happen just to enjoy watching the news media try to cope with the scope of the event with their unscientific reporting. Also I'd admit to some joy watching every religious sect on the planet get saddled with an eternity of cognitive dissonance. It'd go a long way towards reclassifying religion as mythology, while bolstering secularism/humanism. I think it'd be very good for the world as a whole, even if the implications for our long-term survival as a species are pretty grim depending on the complexity and origin of what we find. At least we'd have the warning and knowledge, though somehow I doubt it'll be enough to get humanity to clean up our act. 1 vote −  CALICO July 26, 2018 Link Parent Yeah, Fermi does ruin the fun a bit. The Great Filters keep me up at night thinking sometimes. As much as I'd love to live to see an extraterrestrial intelligence contact us someday, that would be... Yeah, Fermi does ruin the fun a bit. The Great Filters keep me up at night thinking sometimes. As much as I'd love to live to see an extraterrestrial intelligence contact us someday, that would be terrible news in that context. If complex life is very rare, I think the merging of mitochondria with primitive cells is a good candidate for a Filter we've managed to make it through. Whatever that thing is that happened in our neocortices 80-60kya could be another one; the world had been crawling with other H. species until that point — then Sapiens' intelligence skyrocketed for some reason and our ancestors seemed to have genocided their way to the top of the global hierarchy. A Filter that lies ahead though... that really gets one thinking. We're doing a pretty good job of trying to destroy our climate, and the threat of nuclear weapons hangs over my head everyday. Though, considering my location I would never know if the bombs dropped. If there is a Filter ahead of us, both of these seem rather good candidates. We ought to be focusing global effort on reversing climate change and denuclearization in that case. We're doing a few things, but I worry it won't be enough in the end. I can't shake the idea of the Clathrate gun, and even without it things are projected to get really bumpy by the end of my natural lifetime. There are quite a few people concerned that it may be the invention of Artificial Superhuman Intelligence, but for reasons I can't properly express I am not at all concerned about ASI/AGI. In fact, I think we should try to develop one as soon as possible — we may already be past the atmospheric-carbon tipping point, and we've shown time and time that we collectively drag our feet in doing the right thing. An empathetic synthetic superintelligence might be exactly what we need. Of course, maybe there are no Filters ahead of us. It could be that intelligent life doesn't bother to spread out past their home solar systems thanks to the Tyranny of Einstein. I've had more than a few arguments with folks on r/Futurology where they insist that we definitely shouldn't spread out or even try to seed our local cluster. Maybe intelligent life tends to go full transhuman (or transWookiee) and transition from biological to mechanical, then go HAM and cannibalize all their local resources to build a Matrioshka Brain to live within, feeding off the energy of their star until it goes dark. But, that would be a very lonely answer to the question, 'where are all the aliens?'. I would absolutely love the watch the News Media shit a brick if we found life of any sort, anyway. 1 vote − Amarok July 26, 2018 Link Parent This is a good one that's often overlooked. Best candidate I've seen for that is cooking. No, really! I'll take that over the 'stoned ape' theory, anyway. :P I never bought the out of control... Sapiens' intelligence skyrocketed for some reason This is a good one that's often overlooked. Best candidate I've seen for that is cooking. No, really! I'll take that over the 'stoned ape' theory, anyway. :P I never bought the out of control nanotech explanations - self-reproducing nanites in a planetary ocean of grey goo are still 'alive' reproducing, and will still be subject to natural selection. Being a machine doesn't exempt you from nature's inescapable grasp. Seems to me they'd evolve and go on to galactic dominance as easily as anyone. Raping one's planet to the point where it dies before making the transition to being a species that lives primarily in orbital habitats does seem to be a good candidate for a filter. It's considered to be irrecoverable even if life survives due to resource depletion - we've plundered the planet's resources to the point that any stone-age descendants are going to have a far, far harder time climbing back up the ladder than we ever did building that ladder. It may be fair to assume you only get the one shot, and if your civilization collapses it's game over. I think the only ray of 'hope' to be found is the youthfulness of the universe itself. It's a mere 14 billion years, and for that first billion, planets weren't really a thing. We know it took around 4.6 billion years for life to get to us here on this planet, so this process seems to take a very long time. Given the timescales involved in space travel and galactic engineering projects, it may not be realistic to expect the oldest most advanced races to have moved far beyond their own solar systems at this point. The answer to Fermi's question of 'where is everyone' may just be 'at home working on some serious remodeling projects'. My money's on there is no such thing as a 'great filter' - there are just a hell of a lot of really difficult steps which have to be taken, and all of them together just means it takes a very, very long time to travel that road, with a pretty high mortality rate along the journey. Maybe humans will be the one species who isn't happy sitting at home. We are just so desperate to find 'monsters' that we might go to the other side of the galaxy looking for them. We might get out there and find out we are the monsters. − nil-admirari July 26, 2018 Link Parent Its exciting. I think the waters of Europa hold promise as well. Mars is closer and much easier to explore. I suspect what will be discovered first are single celled organisms, most likely... Its exciting. I think the waters of Europa hold promise as well. Mars is closer and much easier to explore. I suspect what will be discovered first are single celled organisms, most likely fossilized. But the extremophiles may well have survived millennia in water. I hope I live long enough to see the discovery. Do you think the depth of water will be important? 1 vote − TreeBone July 26, 2018 Link Parent Very interesting. I hope this develops into something concrete soon. Very interesting. I hope this develops into something concrete soon. −  Neverland July 26, 2018 Link Parent Source: https://theguardian.com/science/2018/jul/25/huge-underground-lake-discovered-on-mars-say-astronomers Mark Sephton, who researches life in extreme environments at Imperial College, London, said that the water being so far under the surface of Mars was not in itself a problem for life. The surface of Mars is bombarded by intense radiation that effectively sterilises the surface, so if life lurks anywhere on the planet, it is likely to be underground. “As long as there is an energy source to exploit and a source of nutrients or raw materials then life is possible,” he said. “High salt conditions are good for maintaining a liquid state but are a challenge for life. If the salt concentrations outside of the cell are higher than the inside then it draws water out from inside the cell and the cell shrinks and desiccates. Life can adapt by synthesising organic molecules to stop the process but there are limits, beyond which the high salinities in the cell interfere with biochemistry and the cell dies,” Sephton added. “So for Mars, some mechanisms which keep water in a liquid state can operate at levels that are too much of a good thing for life.” Source: https://theguardian.com/science/2018/jul/25/huge-underground-lake-discovered-on-mars-say-astronomers −  Amarok July 26, 2018 Link Parent Considering we have lots of extremophiles on Earth that are utterly unphased by lethal radiation levels, I'm curious why this is being touted as a reason for a sterile, lifeless surface. Surely,... intense radiation that effectively sterilises the surface Considering we have lots of extremophiles on Earth that are utterly unphased by lethal radiation levels, I'm curious why this is being touted as a reason for a sterile, lifeless surface. Surely, those radiation levels started out much smaller back when Mars was warm, wet, and had an atmosphere and a molten core. It stands to reason that the rise in radiation would have taken millenia, plenty of time for life to develop the same immunities we see here on Earth in bacteria that evolved to do it inside nuclear reactor pools. If they can do it in a few decades, I'm pretty sure the Martians could do it over millions of years... and probably do a better job, too. :P 1 vote − Neverland July 26, 2018 Link Parent I agree with you. If anything, the radiation and perchlorates on the surface will keep our boring earth based bacteria from infesting Mars too much. I agree with you. If anything, the radiation and perchlorates on the surface will keep our boring earth based bacteria from infesting Mars too much.