Tiny Craters Options

[Guest_Sunspot_*]

http://marsrovers.jpl.nasa.gov/spotlight/o...y/20050427.html

Opportunity Discovers Tiny Craters on Mars

[chris]

Looks to me like there are a few more around as well:

http://nasa.exploratorium.edu/mars/opportu...DIP1992L0M1.JPG

We may even have driven right over one:

http://nasa.exploratorium.edu/mars/opportu...DIP2531L2M1.JPG

I can't find a hazcam image that shows it, though.

Chris

[Marcel]

Looks to me like there are a few more around as well:

http://nasa.exploratorium.edu/mars/opportu...DIP1992L0M1.JPG

We may even have driven right over one:

http://nasa.exploratorium.edu/mars/opportu...DIP2531L2M1.JPG

I can't find a hazcam image that shows it, though.

Chris

Well found ! I'm starting to think that it might not have anything to do with impacts. I don't see any elevated rims on these ones. Maybe the evaporite has voids where the topsoil settles in. Ancient karst process ?

[dvandorn]

I'm starting to think that it might not have anything to do with impacts. I don't see any elevated rims on these ones. Maybe the evaporite has voids where the topsoil settles in. Ancient karst process ?

I think most of the dimples we see are, in fact, meteor craters. The ones without raised rims are just older and more eroded.

However, I also think there is plenty of evidence for sinkhole or karst-like structures out on the plains -- especially the cracks like Anatolia. But while it seems obvious that there are voids down in the evaporite, I think we'll find that these voids are arrayed beneath the weathered concretion layer (the dark soils out on the plains) as a series of cracks defining polygonal crack patterns caused by the drying-out of the ancient seabeds. Such crack patterns are visible in a lot of places on Mars -- they're just filled and covered over here at Meridiani (for the most part) by the concretion erosion residue.

-the other Doug

[John M. Dollan]

I know that there is no chance in heck for this to be true, but these tiny craters made me do a double take when I first saw them. They look exactly like the point of contact between some sand dunes and lighting strikes from when I lived in New Mexico. While we didn't see the strikes that caused the little pits, we did dig one of them up and discovered a foot and a half long fulgerite.

Again, I'm sure we would more than likely spontaneously hear from the Beagle 2 than discover active lightning on Mars, but the resemblances between the pits struck me. I only wish I had pictures of those New Mexico pits to share.

...John...

[Guest_Edward Schmitz_*]

I know that there is no chance in heck for this to be true, but these tiny craters made me do a double take when I first saw them.  They look exactly like the point of contact between some sand dunes and lighting strikes from when I lived in New Mexico.  While we didn't see the strikes that caused the little pits, we did dig one of them up and discovered a foot and a half long fulgerite.

Again, I'm sure we would more than likely spontaneously hear from the Beagle 2 than discover active lightning on Mars, but the resemblances between the pits struck me.  I only wish I had pictures of those New Mexico pits to share.

...John...

I like that. Could they be lightning strikes. There are so many problems with all the other explainations that I've heard.

Does anybody know of hard data regarding lightning on Mars? I have some recollection about dust devils and lightning... Happens with tornados.

I have been racking my brain trying to come up with another explaination. I think this is worth considering.

[djellison]

Not sure - is an electrical discharge even possible in the martian atmosphere?

Doug

[Marcel]

Not sure - is an electrical discharge even possible in the martian atmosphere?

Doug

Didn't see any hard evidence of lighting of some sort on Mars. Anyone else did ?Earth lightning happens because frictional energy between large bodies of water vapour converts into electrical potential differences, which level off on contact (or near contact). I suppose the amount of water vapour (or any other electrical conducting constituent of the Martian atmosphere) is far too low to cause ionic channels for discharging energies, high enough to cause any noticable material displacement.

[Marcel]

Not sure - is an electrical discharge even possible in the martian atmosphere?

Doug

Didn't see any hard evidence of lighting of some sort on Mars. Anyone else did ?Earth lightning happens because frictional energy between large bodies of water vapour converts into electrical potential differences, which level off on contact (or near contact). I suppose the amount of water vapour (or any other electrical conducting constituent of the Martian atmosphere) is far too low to cause ionic channels for discharging energies, high enough to cause any noticable material displacement.

[Bill Harris]

Not sure - is an electrical discharge even possible in the martian atmosphere?

I imagine that dust devils might be a source for lightning. As a youngster I was a mad scientist and one of my creations was a series of Tesla coils, up to 1000KV. Discharges in the air were snappy and lightning-like, but discharges through a clear incandescent lamp (which do not contain a vacuum, but are filled with an inert gas such as nitrogen or argon at reduced pressure) are diffuse and aurora-like. Possible, IMO.

--Bill

[edstrick]

Electrical discharges *are* possible in the martian atmosphere, but lightning is probably *not* possible.

A paper in Science in 1970 reported taking a simulated martian soil <dessicated basalt sand and limonite dust?>, putting some of it in a transparent jar, backfilling the jar with CO2 <dunno if they added any other gasses.. minor gas composition of the martian atmosphere was unknown then>, and sucking it down to martian surface pressure.

When they shook the jar of simulated Mars in the dark, IT GLOWED.

Charges were being separated mechanically, but the 1/2 of 1% Earth pressure gas couldn't support high voltages and the dust discharged with corona discharges.

Mars atmosphere is fairly near the pressures inside neon tubes and fluroescent bulbs, and can easily support diffuse discharges. This is actually a problem for exploration.. high voltage cannot be exposed to the martian atmosphere as it promotes arcing and discharges. Zap. Sput. Oops.

[Bob Shaw]

I suspect that the situation during global dust storms may be *interesting* in terms of electrostatic effects, too - in fact, anything with violent motion may have peculiar sparks and pops associated with it!

Anyone here ever heard of 'singing sand'?

Oh, and there's triboluminescence to contend with when you stress materials, too...

...maybe the hills really *are* alive with the sound of music (and lights! and action!)...

[John M. Dollan]

I know that dry sand and dust can produce electricity, but I'm not sure of any of the other requirements.

And that is an interesting thought... Is it beyond the realm of possibility (if one were to be writing something of a hard science fiction book) to have singing sand on Mars, especially with some of the massive temperatre changes?

If so, I wonder what it would sound like.

...John...

[Bill Harris]

Mars atmosphere is fairly near the pressures inside neon tubes and fluroescent bulbs, and can easily support diffuse discharges.

I forgot to add to my last post here: much like the "plasma globes" available nowadays. Filled with N, Ar, He, etc gas at reduced pressure with a high frequency, high voltage discharge applied, it has a very beautiful diffuse diacharge. I have one. I also have a Wimshurst static electricity machine. The plasma sphere glows a nicely with static electricty as with RF.

So electrical potential under Martian conditions may get "shorted out" before it can build up. The universe is an odd place, no?

--Bill

[tty]

Have a look at this:

http://www.cosis.net/abstracts/EGU05/02197/EGU05-J-02197.pdf

sounds like at least small-scale lightning strikes might be possible