4 ms·
Most of Mars' air was 'lost to space'
- tradersam 10y ago> That liquid water once stood on Mars' surface or flowed freely at times seems obvious. > However, climate models, based on the limited evidence to date of what the atmosphere was like, have struggled to simulate a Mars on which conditions were warm enough to allow lots of liquid water. Much of it would have been locked up in ice, they suggest. Bit contradictory here.
- andrewflnr 10y agoNot really. We know there was liquid water, we just don't know how.
- avenoir 10y agoDo we? Sept. 28, 2015 - We found water! > These downhill flows, known as recurring slope lineae (RSL), often have been described as possibly related to liquid water. The new findings of hydrated salts on the slopes point to what that relationship may be to these dark features. The hydrated salts would lower the freezing point of a liquid brine, just as salt on roads here on Earth causes ice and snow to melt more rapidly. Scientists say it’s likely a shallow subsurface flow, with enough water wicking to the surface to explain the darkening. [1] Aug. 23, 2016 - Maybe not... > "Some type of water-related activity at the uphill end still might be a factor in triggering RSL, but the darkness of the ground is not associated with large amounts of water, either liquid or frozen," Edwards said. "Totally dry mechanisms for explaining RSL should not be ruled out." [2] [1] https://www.nasa.gov/press-release/nasa-confirms-evidence-that-liquid-water-flows-on-today-s-mars https://www.nasa.gov/press-release/nasa-confirms-evidence-th... [2] https://mars.jpl.nasa.gov/news/test-for-damp-ground-at-mars-seasonal-streaks-finds-none https://mars.jpl.nasa.gov/news/test-for-damp-ground-at-mars-...
- lutusp 10y agoYour references discuss evidence for transient liquid water (brine) flowing in the present, not the past. There's good evidence that there was plenty of water on Mars billions of years ago.
- quakeguy 10y agoExcellent! We cannot be sure about water on Mars, at all. Extraplanetary weather forecast is hard, and bound to produce a lot of errors.
- rlkf 10y agoObservations and models don't match, so there is some input that is missing. In this case it seems to be a heavier atmosphere (which has later blown away). Their hopes are that this added assumption will reconcile the observations and models, and thus give a more complete picture on how Mars developed.
- the_d00d 10y agoI disagree. The section you are quoting is titled 'climate conundrum'. The writer is saying that it is visually obvious that there was running water at some point, but climate models do not support this. That is why it is a .....conundrum.
- deleted 10y ago[deleted]
- elastic_church 10y agoI thought there was an isotope within mars water samples (or the dirt) that would allow water to stay in the liquid state at much lower temperatures
- salesguy222 10y agoIt seems the photographic evidence shows there was once flowing water on Mars http://lmgtfy.com/?q=mars+pebbles+rocks+possible+water http://lmgtfy.com/?q=mars+pebbles+rocks+possible+water
- astro1138 10y agoWhat does that mean for terraforming? Establish a magnetosphere first so that solar winds don't drag away an atmosphere?
- theWatcher37 10y agoAt humantimescales it's a non-issue. Any terraforming effort capable of generating an atmosphere over ~100 years or so could more than compensate for losses to space. One great idea I heard to make mars more habitable in general is creating a large magnetic field at a Lagrange point between mars and the sun. A sort of "radiation sunshade"
- M_Grey 10y agoIt's important to realize that when it comes to terraforming you have a tradeoff between speed and cost. The notion of producing an atmosphere in a 100 years is borderline magical, but certainly staggeringly expensive in terms of energy input. Your "sunshade" is another example of a quick, but incredibly pricey option. Most terraforming research tends to be more realistic, and therefore looks at scales of thousands of years for change to take effect, often driven by engineered single-celled organisms in stages.
- dwaltrip 10y agoFor those who are interested, I recommend the terraforming video by the excellent Isaac Arthur: https://youtu.be/ikoNQNj9ZnU https://youtu.be/ikoNQNj9ZnU I discovered his channel a few weeks ago, and was blown away. He has tons of videos that cover all aspects of humanity's potential future in the stars in great detail, and does a very good job of staying grounded in hard science. It seems like he really knows his stuff. The episodes can be quite long (15 - 60 mins), but definitely worth checking out. I've been slowing making my way through them.
- M_Grey 10y agoI'm always looking for youtube channels like this, and that's right in the timeframe I look for. Thanks!
- spraak 10y agoSome of my friends cite 'sources' that humans came from Mars but destroyed the planet's atmosphere and had to escape to Earth. They seem (slightly) less crazy now!
- gallerdude 10y agoAre they in any sort of business to confirm these claims?
- deleted 10y ago[deleted]
- ams6110 10y agoYes they had the technology to travel to another planet but when they arrived they threw it all away and lived in caves and hunted with rocks and sticks.
- SandB0x 10y agoThat's more or less what happens at the end of Battlestar Galactica (syfy version).
- the_d00d 10y agoThe best part is how they tied All Along the Watchtower into the core plot of the show.
- cgriswald 10y agoThat was good, yes. But I recall fans referring to the unknown cylons as "the final five" and then those words somehow coming out of the mouths of characters on the show. That entire bit kind of broke the fourth wall for me, and was completely nonsensical even before the truth was revealed; a truth which made it even more nonsensical. THAT was the best part.
- Filligree 10y agoWhat ending? That series never got renewed. It's a pity; the first season was nice. I'm glad they didn't, though, because an ending like that would have made me scream.