WTF. How have I not heard about this, until now?
Are Those Spidery Black Things On Mars Dangerous?
101–110 of 122 posts
Re: Are Those Spidery Black Things On Mars Dangerous?
#102Pardon my idiotic question, but why don't they just drive over there and check them out? Or are they just in a totally different place than the rover (like asking why someone in North America can't just hop over and check out Uluru)?
Mars is an entire world, it's a big place, we only have two rovers on the planet and they can travel at perhaps 10 km per year .
Why are there so slow? Is this an engineering decision or a limitation of the environment they need to operate in?
Re: Are Those Spidery Black Things On Mars Dangerous?
#103Re: Are Those Spidery Black Things On Mars Dangerous?
#104Earlier quoted context omitted.
Mars is an entire world, it's a big place, we only have two rovers on the planet and they can travel at perhaps 10 km per year .
Why are there so slow? Is this an engineering decision or a limitation of the environment they need to operate in?
It's a combination of a scientific and engineering limitation. The Curiosity rover's power source generates an average of about 1/6th of a horsepower of electrical power. In practice this is used to trickle charge the batteries of the rover over night and provide slightly higher total power during the day for driving, even so we're talking about a fraction of a horse power to drive a nearly one tonne vehicle the size of an SUV. The Opportunity rover is smaller and lighter (180 kg) but also solar powered and so has much less total energy to work with per day.
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.
Re: Are Those Spidery Black Things On Mars Dangerous?
#105Could they not simply be rocky outcrops that are covered and uncovered by seasonal sandstorms?
If that were the case, they would cast shadows.
Not necessarily. The rock may only be a few centimetres underneath the sand dune, in which case it would not appear to protrude out from the dune significantly. There is also the possibility that the "spiders" are black sand[0][1] or silt, as they look suspiciously like some formations on Earth (albeit on a much larger scale):
[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...
Re: Are Those Spidery Black Things On Mars Dangerous?
#106Re: Are Those Spidery Black Things On Mars Dangerous?
#107Re: Are Those Spidery Black Things On Mars Dangerous?
#108Earlier quoted context omitted.
Why are there so slow? Is this an engineering decision or a limitation of the environment they need to operate in?
It's a combination of a scientific and engineering limitation. The Curiosity rover's power source generates an average of about 1/6th of a horsepower of electrical power. In practice this is used to trickle charge the batteries of the rover over night and provide slightly higher total power during the day for driving, even so we're talking about a fraction of a horse power to drive a nearly one tonne vehicle the size…
How much of this is also a reflection of autonomous navigation, risk avoidance, and proceeding at a deliberate pace? While we've got vehicles on Earth which can navigate established highways at, well, highway speed (Google cars), the established road network on Mars is substantially less extensive, and the downside risks (in terms of mission outcome) of even a small mishap on Mars would be very high.
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.
Re: Are Those Spidery Black Things On Mars Dangerous?
#109Earlier quoted context omitted.
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 where…
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 th…
"Lithops", or stone plants, fascinate me: https://en.wikipedia.org/wiki/Lithops
Re: Are Those Spidery Black Things On Mars Dangerous?
#110Earlier quoted context omitted.
Eh, we have other things as well. Meat for one. ;) Maybe you could say that we are meaty pattern matching engines.
Who said computers couldn't be made out of meat?