On the ABC lunchtime news they described the mars rover finding evidence of water, they basically said the rover landed in a riverbed and drilled down 6 inches or so to find the evidence in the clay.

I find it rather counterintuitive that they could go to a planet and find an ancient riverbed for the rover to explore in a seemingly perfectly preserved state. After all, mars has an atmosphere, it has dust and sand storms, and it has wind.

In millilons(?) of years since the river flowed why hasn’t the river filled up with dust and sand?

Anywho said:

In millilons(?) of years since the river flowed why hasn’t the river filled up with dust and sand?

It did.

Yet it was still devised to be a riverbed from whatever research was done. Why question without relevance?

Anywho said:

In millilons(?) of years since the river flowed why hasn’t the river filled up with dust and sand?

It did. Once dust blows into the riverbed, it doesn’t stay there forever more. Are you asking why the rover only had to dig 6 inches or so? I don’t know the answer to that part.

Divine Angel said:

Anywho said:

In millilons(?) of years since the river flowed why hasn’t the river filled up with dust and sand?

It did. Once dust blows into the riverbed, it doesn’t stay there forever more. Are you asking why the rover only had to dig 6 inches or so? I don’t know the answer to that part.

You already answered it then went on to deny that you did.

Divine Angel said:

Anywho said:

In millilons(?) of years since the river flowed why hasn’t the river filled up with dust and sand?

It did. Once dust blows into the riverbed, it doesn’t stay there forever more. Are you asking why the rover only had to dig 6 inches or so? I don’t know the answer to that part.

Why wouldn’t it stay there forever more? Rivers are lower than the surrounding landscape so why wouldn’t they fill up and remain filled?

The main contributor to erosion is water action, so without water any erosion effects will be very slow.

Anywho said:

Divine Angel said:

Anywho said:

In millilons(?) of years since the river flowed why hasn’t the river filled up with dust and sand?

It did. Once dust blows into the riverbed, it doesn’t stay there forever more. Are you asking why the rover only had to dig 6 inches or so? I don’t know the answer to that part.

Why wouldn’t it stay there forever more? Rivers are lower than the surrounding landscape so why wouldn’t they fill up and remain filled?

it is possible to have subsurface water flows… happens all over the place here in Earth… Don’t have to look too hard to find what appears to be a dry water course only to dig down and find water…

monkey skipper said:

{empty quotes}

How difficult would water managerment of water be after the discovery of such a resource?

i would hazard a guess that with the very thin atmosphere that not a lot of dust actually gets blown about. it just looks that way when we see dust storms from space. also if the river beds filled and stayed like that then after a couple of billion years, a more realistic time frame for last river flows, then you would expect the surface to be more featureless than it is.

diddly-squat said:

Anywho said:

Divine Angel said:

It did. Once dust blows into the riverbed, it doesn’t stay there forever more. Are you asking why the rover only had to dig 6 inches or so? I don’t know the answer to that part.

Why wouldn’t it stay there forever more? Rivers are lower than the surrounding landscape so why wouldn’t they fill up and remain filled?

it is possible to have subsurface water flows… happens all over the place here in Earth… Don’t have to look too hard to find what appears to be a dry water course only to dig down and find water…

I would have thought it would be very difficult to find a water course that had not had flowing water for millions (or billions?) of years, and that having identified one, excavation would be needed to find the original riverbed.

That is what I found counterintuitive.

Farking Indians trying to tell me my computer’s borked. This one got an earful.

Sowwy Fred Wong.

Because the martian atmosphere is thin—about 1% as dense as Earth’s at sea level—only the smallest dust grains hang in the air. “Airborne dust on Mars is about as fine as cigarette smoke,” says Bell. These fine grains reflect 20% to 25% of the sunlight that hits them; that’s why the clouds look bright. (For comparison, the reflectivity of typical martian terrain is 10% to 15%.)

http://science.nasa.gov/science-news/science-at-nasa/2003/09jul_marsdust/

>and it has wind.

So, the dust that’s small enough to get blown around will still get blown around, in those regions particularly prone to winds. This might well include some of the alleyways formed by running water in the distant past. And some of those apparently water-eroded features might themselves actually have been formed by the wind, in the days when Mars had a thicker atmosphere.

Anywho said:

diddly-squat said:

Anywho said:

Why wouldn’t it stay there forever more? Rivers are lower than the surrounding landscape so why wouldn’t they fill up and remain filled?

it is possible to have subsurface water flows… happens all over the place here in Earth… Don’t have to look too hard to find what appears to be a dry water course only to dig down and find water…

I would have thought it would be very difficult to find a water course that had not had flowing water for millions (or billions?) of years, and that having identified one, excavation would be needed to find the original riverbed.

That is what I found counterintuitive.

presumably if there is water there now, there has been water there for a long time…

do you have link to a news article or publication that relates to this story?

diddly-squat said:

Anywho said:

diddly-squat said:

it is possible to have subsurface water flows… happens all over the place here in Earth… Don’t have to look too hard to find what appears to be a dry water course only to dig down and find water…

I would have thought it would be very difficult to find a water course that had not had flowing water for millions (or billions?) of years, and that having identified one, excavation would be needed to find the original riverbed.

That is what I found counterintuitive.

presumably if there is water there now, there has been water there for a long time…

do you have link to a news article or publication that relates to this story?

It was on todays midday report on the ABC, I admit I have no interest in the mars rover at all, but I just found the presentation counterintuitive so I thought I’d pose my questions here.

Thanks for the responses, I’ll check again later but I’m on my iPad and finding quoting to be a nightmare so I’ll quit responding (there seems to be some sort of glitch).