This stuff blows me away. I think, holy crap this planet has all sorts of real exo-planet kinds of weirdness. I love the idea of reverse icicles although for the life of me I can't imagine what would hold them up once the CO2 gas has vaporized out.
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.
Certianly do seem to follow a frost/freeze pattern in some ways, even if they do tend to have a bag of flour type directional point. So can see the reverse icicles. Question is it a biological or a chemical reaction. I do feel that it could be chemical but thats just a hunch and that is what makes it a holy crap mystery.
Is there any chance they could be plants? relying on underground water reserves and appearing every spring to throw around some pollen before slinking back into the cool darkness.
I'm not a xenobiologist so I couldn't quantify the relative chance of them being 'plants'. But this is the kind of stuff we can speculate on.
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.
Why not literally a plant? Like leafy, relies on water, comes from a small seed, reproduces via pollen/wind, based on a cell structure.
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.
Because plants, of the leafy green variety, have a complex evolutionary history with lots of side trips (like lichen and mold and algae). Further earth based plants are based on the same basic DNA structure as earth based animals.
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 ...")
Yes, they could. But can you include some reasoning with how they would have done that? Some sound more likely than others.
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?
If we ever confirm life on Mars (or anywhere else for that matter), I really hope we don't find that it shares a common ancestor with life on Earth. Panspermia is cool, but two instances of abiogenesis in a single solar system? That is huge.
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.
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.
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.