Are Those Spidery Black Things On Mars Dangerous?
npr.org
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In particular, the geology of Mars in an incredibly fascinating topic. If you're looking for a good primer on the subject, I highly recommend Mapping Mars by Oliver Morton.
Mapping Mars contains a history of the science, highlighting the major contributors to the field and augmented with interviews from such notable science fiction authors as Kim Stanley Robinson. A good discussion is, for example, how much water exists on the planet. Consensus is now that there is water somewhere, but exactly how much water, where it sits, how it flows: great questions that are attacked with lucid explanations.
Hats off to NASA and human curiosity for this grand adventure.
"Peaks of knowledge" have existed throughout our collective history and the single uniting feature of each is that they are never peaks. Local maxima perhaps, but the upslope of discovery always reasserts itself eventually. Afaik, nothing indicates that the future will differ in this regard.
1. http://en.wikipedia.org/wiki/Rover_%28space_exploration%29#A...
2. http://en.wikipedia.org/wiki/Opportunity_rover#Design_and_co...
3. http://en.wikipedia.org/wiki/Curiosity_rover#Specifications
http://en.wikipedia.org/wiki/Mars_Polar_Lander http://en.wikipedia.org/wiki/Phoenix_(spacecraft)
According to Wikipedia, http://en.wikipedia.org/wiki/Martian_geyser this only occurs in the south polar region and Curiosity is near the equator.
(Gale Crater: http://en.wikipedia.org/wiki/Aeolis_quadrangle)
If the goal were merely speed we could build faster rovers but to do so would mean removing a lot of scientific instruments so we'd be able to get to different locations but then we'd only be able to do a tiny amount of science compared to what we can do with Curiosity or Opportunity.
So: for both engineering reasons (power supply & motors vs. scientific payload) and risk mitigation, you end up with systems which are mobile, but only at a very slow crawl.
Incidentally: Mars also limits the options for higher-mobility systems. The atmosphere is too thin for conventional winged aircraft to be terribly effective (they'd have huge wingspan requirements relative to payload, and very large turning radius and stall speeds). Balloons would be impractical. The gravitational force is high enough that a multi-hop lander relying on rocket thrust would be expensive.
Some sort of robotic tumbleweed / beachball might work, though unless these had some means of getting themselves unstuck, would likely just scatter over an area of terrain (erm, marscape?), before settling against an outcropping or at the bottom of a ravine, crater, canyon, etc.
One part of me wants to build another Curiosity style rover and catch the next Earth/Mars orbital cycle and put it down near stuff like this.
I can believe folks would find this as inspiring as looking back at the planet from the Moon.
First, we'll need to be a bit loose with our definitions since 'plant' means a very specific kind of thing.
So if we define a 'plant' as a chemical process which creates structure in the presence of certain chemicals such that a transformative chemical reaction is enabled whereby energy in the form of sunlight or heat is used to build additional structure. Then we can see if there is a chemical mix that would have this characteristic output.
It is critical to note though that this would also classify a stalactite as a 'plant' which converts calcium carbonate into 'structure' (in this case rock) by exploiting a transfer agent (water).
Interesting questions would be "Why vanish in the winter?" what ever hypothesis we come up with has to include the observed effect and behaviors. This is my biggest issue with my 'frozen geyser' hypothesis, it seems like they would continue to exist during winter.
Finding better imagery from HiRise would be good too, in particular it would be useful to know if these were vertical structures or not. that would show up as shadows.
Lots of fun to think about.
We have plants in the desert here on Earth that blossom once every X years or decades. Is there a reason such a "plant" could not have survived the harsh later years of mars post surface water?
Bonus idea: if these are plants relying on ground water, their location would give away the position of said ground water. They could be mapped and their spacial density used to find source pools for humans to tap.
So while it is not "impossible" that an equivalent to plants evolved into exactly one species or micro-eco-system which exists in this one place on Mars, the chance that this occurred and didn't cause the whole planet to have evidence of their existence is really really small.
But don't let that discourage you from trying various plant hypotheses. The way to pursue that is to then try to figure out what things would be true if they were plants, and see if any of the data we have from Mars would allow you to get closer to proving or disproving your hypothesis. The last time I checked you could ask for and get the a copy of the raw data from JPL if you asked for it (well not some 'give me all your data' kind of ask, but "I'd like to get HiRise imagery from this part of the planet ...")
The panspermia theory [1] is based on the idea that perhaps some forms of life could exist in space as it transits from place to place. One of the things that has always bothered me about that hypothesis is the orbital mechanics. Which is to say if you posit a supernova or other energetic event that accelerated a planet (or fragments of that planet) into space, and somehow the life on those fragments survived both the radiation and the effects of vacuum on volatiles, and then it arrived in our solar system, what would the relative velocities be of that material with respect to our planets? And then when that material impacted a local rocky planet how much energy would be released and how would it survive that?
The 'primordial soup' theories have thus always held more interest for me as being more probable. With papers like this one: http://arstechnica.com/science/2012/10/simple-reaction-makes... lending a bit of narrative around how it might have occurred. But the primordial soup theories also need evolution to get from a happenstance chemical mixture into something like multi-cellular organisms.
So follow your chain of reasoning and see what questions it leads you to:
"down from an external source" ...
From where?
How did the plant get there to come down?
What is needed to survive a fall from space? At what velocities?
Etc.
Here's to hoping it's life, but not as we know it.
>"I really hope we don't find that it shares a common ancestor with life on Earth". Could you give a definition here, please?
I cannot respond to you directly, but sure. When I say I hope there is not a "common ancestor" I mean that I hope life on Earth and life anywhere else we may discover it do not have "common descent" (http://en.wikipedia.org/wiki/Common_descent). That is strongly believed to be the case with all life we have encountered so far. This is also a pretty good wikipedia page about this: http://en.wikipedia.org/wiki/Last_universal_ancestor
For plants to be on Mars, either A) the immeasurably chaotic process of evolution yielded carbon-based, cellular, stationary, metabolizing, photosynthetic, reproductive things on two planets with vastly different geological and climatic histories, or B) Earth-borne plant material, which has evolved to the point that it can only produce a viable organism in certain rather specific environmental niches on its home planet, has somehow reached a foreign planet and developed into a more-or-less thriving colony of vegetation upon it.
Neither of those seems terribly likely.
We obviously are operating with an extremely limited dataset (currently of size "1"), but there are a few things we can look at that may tell us something about the likelihood of particular characteristics evolving.
We know that flight has evolved on Earth at least four completely distinct times (no common flying ancestors): birds, bats, bugs, and pterosaurs. The basics of eyes are thought to share a common ancestor, but complex image forming eyes are thought to have evolved dozens of times.
I'm sure there are many better examples; I have only studied biology in my spare time as an adult, so maybe a biologist can step in.
The basic idea though is that since the driving force behind the change is not random certain general ideas are likely to keep on popping up over time. Now, are the building blocks likely to be the same? Hard to say, the chemistry for carbon based life works particularly well, but there are hypothetical alternatives. I can't speak to which is more likely than the other.
The question of "how likely is this" is really quite involved.
Simplest answer would be some seasonal event (either a CO2 snow or annual dust storm) covers the markings.
http://upload.wikimedia.org/wikipedia/commons/0/0c/PIA11858_...
Maybe you could say that we are meaty pattern matching engines.
Saying that humans are pattern matching engines seems equivalent to saying VW Bugs are internal combustion engines to me though.
That is what it means to be uniquely human: to match patterns, overzealously.
I'm not sure if these two pictures are of the same phenomenon, actually?
-- a commenter on that page, Melissa Swanson
That's incredible. Is that really possible? I wonder why the rover doesn't check them out? It seems weird it's digging through soil looking for chemicals possibly related to life when there's potential life out in plain view.
NASA has some very strange priorities.
Clearly a team of brilliant scientists has not failed to consider the possibility of exploring these strange spidery features, but they have decided against it for the time being.
It doesn't really make sense to assess their "strange priorities" as an outsider looking in with very limited knowledge as to how their decision making process actually works.
A cessna would need wings as large as a 747 and be traveling about mach 1 to take off, iirc.
[2]: This is a sand dune on a sand island, but has some black discolouration from rock just below the surface. I'm not sure how far down this rock extends, but its visibility varies depending on the time of year and number of visitors to the island. Note that there is also some grass (brown) and other vegetation (green) around the edge of the clearing (particularly on the southern edge), which is difficult to distinguish from the black rock.
[3]: Same island, different clearing. There is still some vegetation in the picture, but it's easier to see the black sand and rock underneath the top layer of white sand.
Try playing with the time slider at the top of the page to see how the exposure of the rock changes.
[0] https://en.wikipedia.org/wiki/Black_sand [1] https://en.wikipedia.org/wiki/Heavy_mineral_sands_ore_deposi... [2] http://www.nearmap.com/?ll=-27.194111,153.379091&z=21... [3] http://www.nearmap.com/?ll=-27.280641,153.410605&z=20...
Everything is dangerous. The key to mitigating that danger is planning ahead for it. A leaf seems harmless, but infection from a cut the leaf gave you could kill you. A marshmallow is fluffy and soft, but if you swallow it without chewing, it could expand and suffocate you.
Asking if something is dangerous is ridiculous. Asking what it is and how to safely handle it is not. The article does a much better job portraying this than the headline does.
https://www.google.com/search?q=site:news.ycombinator.com+be...
It's been mentioned 19 times already in the last month according to Google.
Either way it doesn't seem very constructive - or gentlemanly - to downvote an informed - and depending on the reader informative - comment.
http://www.reddit.com/r/science/comments/10vrag/are_those_sp...
http://hirise.lpl.arizona.edu/ESP_024736_2565
Edit:
Ahah, here we are, about 1km:
http://hirise-pds.lpl.arizona.edu/PDS/EXTRAS/RDR/ESP/ORB_024...