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-   -   Valles Marineras Origin and Origin of Asteroid Belt Linked? (http://www.physicsforums.com/showthread.php?t=563153)

elroyjetsn Dec27-11 03:57 PM

Valles Marineras Origin and Origin of Asteroid Belt Linked?
 
The aerial view of Valles Marineras has a strangely familiar look to it. As a kid I would shoot BB's at all sort of fruit and mud and stuff. Sometimes I'd hit a rotten apple or tomatoe with a glancing shot that would rip open a gaping tear for a distance as the BB would enter, force material out of the fruit thru the tear and afterword the tear would fill with soft material and juice(if the tear is facing up). I suspect that a similar event has occured on Mars at some time in the past resulting in a trauma zone that is now called, "Valles Marineris".

Of course this would be a "punch-through" of a much greater scale. An asteroid or comet striking the planet at a low angle of insidence that is large and dense enough may have penetrated the lithosphere and blasted through the softer interior opening a huge tear in the lithosphere sending a 'rooster tail' of ejecta all around and into open space. The impact object would have no doubt been reduced to a much smaller size by the time it exited the lithoshpere again that is if it was able to do so at all.

Has such a theory ever been suggested?

Wayne

Chalnoth Dec28-11 02:01 AM

Re: Valles Marineras Origin and Origin of Asteroid Belt Linked?
 
Quote:

Quote by elroyjetsn (Post 3685646)
The aerial view of Valles Marineras has a strangely familiar look to it. As a kid I would shoot BB's at all sort of fruit and mud and stuff. Sometimes I'd hit a rotten apple or tomatoe with a glancing shot that would rip open a gaping tear for a distance as the BB would enter, force material out of the fruit thru the tear and afterword the tear would fill with soft material and juice(if the tear is facing up). I suspect that a similar event has occured on Mars at some time in the past resulting in a trauma zone that is now called, "Valles Marineris".

Of course this would be a "punch-through" of a much greater scale. An asteroid or comet striking the planet at a low angle of insidence that is large and dense enough may have penetrated the lithosphere and blasted through the softer interior opening a huge tear in the lithosphere sending a 'rooster tail' of ejecta all around and into open space. The impact object would have no doubt been reduced to a much smaller size by the time it exited the lithoshpere again that is if it was able to do so at all.

Has such a theory ever been suggested?

Wayne

Unfortunately, it doesn't work like that for larger collisions. Basically, when collisions get big enough, they tend to make large, nearly-circular craters no matter the impact angle. More likely Valles Marineris was the result of tectonic activity in Mars' past. Mars, being smaller, has cooled faster than the Earth, and has less weathering. As a result it tends to have much larger tectonic features.

elroyjetsn Dec29-11 07:26 AM

Re: Valles Marineras Origin and Origin of Asteroid Belt Linked?
 
Quote:

Quote by Chalnoth (Post 3686144)
Unfortunately, it doesn't work like that for larger collisions. Basically, when collisions get big enough, they tend to make large, nearly-circular craters no matter the impact angle. More likely Valles Marineris was the result of tectonic activity in Mars' past. Mars, being smaller, has cooled faster than the Earth, and has less weathering. As a result it tends to have much larger tectonic features.

On the West end of the valley there's a pretty large crater that somewhat offset from the "tear". But, I'm thinking an event of that magnitude might have taken an hour or so to play out and the planet's rotation would have distorted the trajectory. The region designated, "Noctis Labarynthus" being a possible entry point. The East end(Eos Chaos region) of the valley there appears to be a enormous amount of material flowing in all direction and further West there a large belt of impact craters, consistent with such an event. I suppose that may be circumstantial?

I speak as an amateur biologist with an interest in physics. LOL.

Chalnoth Dec29-11 11:50 AM

Re: Valles Marineras Origin and Origin of Asteroid Belt Linked?
 
Quote:

Quote by elroyjetsn (Post 3687765)
On the West end of the valley there's a pretty large crater that somewhat offset from the "tear". But, I'm thinking an event of that magnitude might have taken an hour or so to play out and the planet's rotation would have distorted the trajectory. The region designated, "Noctis Labarynthus" being a possible entry point. The East end(Eos Chaos region) of the valley there appears to be a enormous amount of material flowing in all direction and further West there a large belt of impact craters, consistent with such an event. I suppose that may be circumstantial?

I speak as an amateur biologist with an interest in physics. LOL.

Yeah, I suspect it's largely a coincidence. Such geological features generally occur because of the drifting of the planet's crust, which is driven by the currents in the mantle below the crust. An impact on the surface isn't going to have much of an effect on those underlying currents.

Now, such an energetic event may potentially have an impact on when a tectonic shift occurs, but it doesn't really change the underlying causes of the shifts, so I don't think it can be responsible for a feature like a canyon, especially as such features are built up from a large number of tectonic shifts produced over a large span of time.

Hypervelocity Jan7-12 02:49 PM

Re: Valles Marineras Origin and Origin of Asteroid Belt Linked?
 
We are speculating on the same thing a bit about the "crater chains" on Phobos, Vesta, and some other asteroids.

We have come to the conclusion they are formed by ring fragments, with the orbit decaying slowly enough to allow individual rocks to come in and bounce along the surface , then ejecting or slowing enough to finally plow into the surface.
There does seem to be a few of the chains that tail off at a parabola like a stone skipping.

Mars has such a low density atmosphere, it is not totally outside the realm of possibility. One of the reasons it is so hard to land there.

Chalnoth Jan7-12 03:10 PM

Re: Valles Marineras Origin and Origin of Asteroid Belt Linked?
 
Quote:

Quote by Hypervelocity (Post 3700436)
We are speculating on the same thing a bit about the "crater chains" on Phobos, Vesta, and some other asteroids.

We have come to the conclusion they are formed by ring fragments, with the orbit decaying slowly enough to allow individual rocks to come in and bounce along the surface , then ejecting or slowing enough to finally plow into the surface.
There does seem to be a few of the chains that tail off at a parabola like a stone skipping.

Mars has such a low density atmosphere, it is not totally outside the realm of possibility. One of the reasons it is so hard to land there.

Not for a feature that big, though.


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