DescentBB

Check out this rather large image of Mars: http://nssdc.gsfc.nasa.gov/image/planet ... globe1.jpg

It's centered on Valles Marineris which isn't so strange as it kinds of dominates the planet. It is 4000 kilometres long and reaches 10 km in depth. Think about that for a second, it reaches from LA to NY, and it's as deeper than Mt Everest is tall. Try calculating the volume of material shifted to create it, and the forces required. Hell, I don't want to even BEGIN doing that.

We'll ignore Olympus Mons, the Solar system's tallest mountain and largest volcano. It's 5 times higher than Mount Everest, and pokes clear of the atmosphere!

Anyway, back to the Valles Marineris...

Check the photo again, and ask yourself what's wrong with it? Can't see anything? OK, so check out this pic of the Grand Canyon:

http://www.spaceimaging.com/gallery/iow ... 2_1024.jpg

Please ignore the watermark, that's just to stop peeps ripping the image off...

Anyway, now compare the Grand Canyon and Valles Marineris. See the difference? Valles Marineris is almost entirely straight! The GC isn't anywhere NEAR straight, in fact, I challenge you to find ANYTHING straight in that image! Now, look back at VM. What do you see now?

Yeah, you got it. The WHOLE THING is straight. I mean, from start to finish, IT'S ENTIRELY STRAIGHT. Not only is it straight, but look closely at a whole HEAP of straight features, connected to, and unconnected to the central canyon structure.

Now, where have you seen any geography that's straight? And straight over a 4000 kilometre distance? Yeah - NOWHERE on Earth, that's for sure.

What I want to know is - what the hell is up with that? I mean, there are depressions that are straight, and aligned with the central canyon system, and some which are slightly skewed from the parallel, but still straight.

I admit, I know very little geology, and not a whole lot about Martian geology (well, who does?), but it seems to me that the VM is not a natural phenomenon, at least as we understand it now.

Looking at the image, it's clear that an enormous amount of erosion has occured in the canyon. What I want you to do is to mentally remove the erosion, and what do you get? Yeah - more straight lines.

So, I want to know how it's possible for a planet to have such a feature. It's not an impact, those make round, or oval holes, plus, an impact that size would bulge Mars on the opposite side.

To me, it looks like *something* has "raked" Mars. Something spikey, and something that ground along the surface of Mars digging out not just the main canyon structure, but also the weird straight features surrounding it.

Parallel lines don't generally occur large structures naturally, unless you look at biology, and the VM is rather obviously NOT biology.

So, tell me, am I seeing things, or do you see it too? And what possible explanation could there be? This has been sitting around in the back of my head for some time, and I am absolutely buggered if I can come up with ANYTHING to explain it.

Yep. Mobius has smoked the crack today.

Impacts at high angles make craters. Impacts at sharp angles make lines. Go out to the nearest sandbox, playground, etc. and take a large rock. Throw it down, and what happens? Crater. Now, throw it like you're trying to skip it across a pond -- now what happens? If you do it right, you should get a nice linear gash with a crater at the end.

Now, the thing about that gash is it goes like halfway around the planet -- and that's pretty impressive. I can't imagine anything hitting any planet at such an angle that it would cut a straight gash. So, let's throw out the "impact" hypothesis -- it's simply too long to be something scratching the planet, and it does curve a little bit.

Since it's 4 AM, though, I may as well speculate: perhaps it's natural erosion.

You say "but wait, it looks nothing like the grand canyon!" Well, of course not -- it's not on the same planet, and not formed by the same forces. The grand canyon was formed by water, right? Water tends to make curves like you see in the GC pic, because its driving force is gravity -- it's going downhill, so it follows the "downhill" that already exists, which tends to be curvy. But what does pure wind-driven erosion look like? Wind goes in big huge cyclic cells. From a ground-level observer, it looks like it's going in a straight line. Now, I don't think we ever see large-scale, pure-wind erosion on this planet -- but it's possible you might get such a thing on Mars.

Who am I kidding? It's 4 AM; I'm less coherent than Mobi :)

In defence of Mobius's contention, isn't there a saying: Nature abhors a straight line?

Another point has to do with atmospheric density.
We know now that the atmosphere on the surface of Mars is extremely rarefied. Iâ??m wondering what it would be at the bottom of not only this deep trench but also others on Mars?
Canâ??t seem to find any information of this on relevant web sites.

hmm probably its a weather effect. the mars-orbit is a very excentric ellipse and so are the seasons. in summer times (a mars year is 686 days) the southpole icecap completely melts and temperature goes up to +100c on the southglobe, while the northpolecap still stays. temperatures on mars vary between +100c and -140c wich is responsible for some incredible storms on the equator. now imagine that going on for millions of years now, that could cause for sure such canyons.

Arol wrote:In defence of Mobius's contention, isn't there a saying: Nature abhors a straight line?

Tell Newton that.

At 10 km deep, the trench is hardly a weather phenomenum, The trench is in all likely-hood a pressure fracture akin to a ball of clay cracking as it dries out.

I hope Sudanamaru doesn't see this...TEH ALIENZ!!!11!

obviously, a star destroyer crashed into mars a long long time ago.

it's the perfect shape!

woodchip wrote:At 10 km deep, the trench is hardly a weather phenomenum,

Sorry Woody, I guess that I went a bit of the line of the thread!
I did not mean to imply that the trench was caused by weather.
Rather, I had hoped that somone monitoriing this thread could point me to a site where I could get info regarding atmospeheric density on Mars. As I stated on the surface it is negible, what I getting at is that 10 klicks down it might be denser, and therefor a more likely place to look for signs of life.
No not little green men.

Arol, I have also thought looking for life at the bottom of the trench would be the most logical. The grand canyon is similar in that the temps at the bottom of the gc are significantly warmer than up on the rim. Perhap vm's bottom topography has small pockets of water that are so far undetectable.

Yeah - my thoughts too - best place to look for life should be down deep, at the bottom of VM where the pressure is highest.

It's possible VM was formed by a buckling techtonic plate, but it doesn't seem likely to me - given the straight nature of it, or the complete lack of surrounding effect such a huge catastrophe would likely cause.

Also, Mars a large portion of the surface of Mars is billions of years old, which tends to indicate that techtonic action - if it ever existed on Mars - is long dead. The surface of Earth tends to get replaced every billion years or so. (A few places have stayed on the surface though, like the USA and parts of Australia/Antarctica).

Telling Newton things don't like straight lines, he would tend to agree I think. His laws apply most directly to hypothetical situations. NOTHING ever travels in a straight line. Forces ALWAYS act on moving objects. Drop an apple? It just LOOKS like it travels straight to the ground, but it does NOT. The Coriolis force affects it, and it's also travelling very quickly through space, with the Earth...

It seems unlikely to me that the canyons are created by water, or CO2 for that matter. They would resemble the GC otherwise.

Seems to me it COULD have been formed by water, but only under the most extreme circumstances, like releasing about the same amount of water on the whole Earth and letting ir run for 100,000 years from a lake into a depression - that might tend to make a straight channel. However, this still wouldn't explain the straight lines AWAY from the VM, pointing in the same direction.

We know Mars has seen some very very severe conditions, and I think the above scenario is possible, perhaps even likely, given that there could have been simply stupendous amounts of ice backed up behind an "ice dam", which burst once, or repeatedly over hundreds of millions of years.

But my questions still remain, where do the straight lines outside th VM come from? Why are they perfectly parallel in many cases? What is the nature of this straight depressions? Are they the same age as the Canyon? Was the VM carved in one catastrophic episode, or a number of them? What caused such amazing outflows? How could they have been repeated over eons?

How on Earth does bedrock get carved 10 km deep? It's all very vexing!

Vertigo 99 wrote:obviously, a star destroyer crashed into mars a long long time ago.

it's the perfect shape!

Last time I checked, a Star Destroyer was only a couple of klicks long. It wouldn't even make a DENT compared to the VM.

way to ruin my fun, mobi.

Super Star Destroyer, G. Word.

Im thinking: one very large earth quake, or caught the wrong end of a planet breaking up.

Im doubting its entirely straight, it is on a curved planet, and that photo is taken from a fair distance away, so it looks straight.

I think it looks like an eyeball that has been popped and the stuff inside is oozing out.

Good job it's not a mind test 'cause it looks to me very similar to somthing that i'm not allowed to say.

we have a few biggies, but their hiddern under the wet stuff, like the Marianas Trench 11k down.

woodchip wrote:...I have also thought looking for life at the bottom of the trench would be the most logical.

Mobius wrote:...Yeah - my thoughts too - best place to look for life should be down deep, at the bottom of VM where the pressure is highest.

Did a little digging into the possibility of water in the deeper crevasses on Mars.
Asked an acquaintance of mine David Brin, whoâ??s not only a top notch SF writer, but also an astrophysicist who used to be with JPL, hereâ??s what he said:
â?¦ yes, deep crevices would help keep denser atmosphere. But no, the RATE of increase in pressure would be too low. While a little moisture might accumulate, the air pressure would stay too low for much water to gather
I particular like the phrase: for much water, as it opens up the possibility of, if not water then at least moisture. Which would give some chance for at least some primitive form of life to develop.
I recall someone once wrote that life is so tenacious, that even in the most hostile environment thinkable it will establish itself if there is the barest requirements for its survival.
Which is why life signs have been found; in some form or other, on the peaks of the highest mountains and in the deepest crevasse of the deepest oceans on this planet.
So thereâ??s still hope.
But it will be some while yet, as I canâ??t see dune-buggies of the type crawling around the surface of Mars these days going for little jaunt down a 10 km. deep trench.
He also recommended a book Martynn Fogg called TERRAFORMING, which deals with this subject.

Pehaps an electrical discharge between Mars and another large celestial body?

Mobius wrote:The Coriolis force affects it, and it's also travelling very quickly through space, with the Earth...

Ahh, good old coriolis, I mean- ugh. My point is that nature does, in fact, very much love straight lines... it's just that we don't see it much because gravity is always getting in the way.

(yeah, actually, if you drop something, it will move slightly east as a result of coriolis - not that you can measure it, but that's besides the point)

Looks tectonic to me. Compressional and extensional events on earth nearly always result in linear features. Erosional features are probably subsequent to the initial formational event.

That's just my gut instinct; we never got into specific planetary features in my Planetary Geology course. And if we're going to drop names I'll boast that I took the class from Steve Squyres!

A really long time ago, there was a battle, and an alien beam weapon grazed the planet there, you see the wound in the planet now filled in by sediment.




I agree, looks tectonic to me

It's the impact trench caused by a fragment of the planet that was shattered by Jupiter when it arrived in the solar system and broke apart said planet into the asteroid belt where one of those asteroids hit Mars and the result was Phobos and Deimos and another piece of the obliterated planet created the great red spot of Jupiter.

I really don't think Jupiter "arrived" in the system.

But, I agree in the breaking up of a planet. I said that already.

lol

Arol wrote:

woodchip wrote:
Asked an acquaintance of mine David Brin, whoâ??s not only a top notch SF writer, but also an astrophysicist who used to be with JPL, hereâ??s what he said:

Lucky you. I've enjoyed Brins novels especially the uplift trilogy.

Mob-messenger's explaination is the best one so far, maybe not the most scienctificly correct, but definitly the best!

Arol wrote:Mob-messenger's explaination is the best one so far, maybe not the most scienctificly correct, but definitly the best!

!!!DOES NOT COMPUTE!!!

!!!DOES NOT COMPUTE!!!

Mobius wrote:Also, Mars a large portion of the surface of Mars is billions of years old,

How can that be when the universe is only 6,000 years old?

Dedman wrote:How can that be when the universe is only 6,000 years old?

How about:

"God, being a tricky fellow, who likes his practical jokes, created the Universe in 7 days. In the process of creating said Universe (a very big place indeed), he planted evidence EVERYWHERE that would make it appear that the Universe was between 12.8 and 13.7 gigayears (billion) years old, thus proving his omnipotence."

"Thus, the surface of Mars appears to be billions of years old, and as far as every test we can devise can show us, it IS billions of years old, and acts as if it were billions of years old. Therefore, despite the fact that Mars was created only 6,000 years ago, we must treat it as if it was created billions of years ago to obtain experimental results which are congruent with reality, which is absurd because God made it much more recently."

I don't know where you get the idea that the universe is only 6k years old, because the bible certainly doesn't say that.

We don't care what the bible says, we're having fun. Two thousand years here and there matter little compared to billions anyhow. Now run along. shoo.

Ok, I'll tell you what it says, it says the world was created in six creative "days." "Days" could be any length of time, not just 24 hours.

You've had your say. Now will you shoo?

No

One theory that I tend to agree with is that Valles Marineris is a sort of 'rip' or 'tear'.

A quarter of the way around Mars is the Hellas Impact Basin. The Hellas meteorite plunged into the Martain surface and penetrated the crust. The immense tidal pressure of the meteorite pushed back a large portion of the planet's (then molten) magma. On the opposite side of the planet are the Tharis Montes, and Olympus Mons - on top of the Tharsis Bulge. I believe the magma waves hit the opposite crust on the other side of the planet, causing the bulge to rise and the volcanoes to form. The obvious stretching energy this would cause around the planet is enough to actually cause a huge tear similar to the Valles Marineris. Look below for my cheap diagram...



There is also the Elysium bulge, which may have been formed in a similar way by the impacts of Isidis and Arygre.

All of these major impacts are on the southern hemisphere, which lies on average 3km higher than the northern hemisphere - and is far far more heavily cratered. What could make 3km of crust disappear AND the tharis bulge appear AND the valles marineris form?

Well, lets say a small planetesimal appproached Mars from the south. Once it crossed through the 'Roche Limit' it was immediately torn apart by its gravity. These huge fragments could have given Mars a hemisphere-wide meteorite shower. This could have created the process above AND provided enough force to 'knock off' the crust on the other side of the planet. This is why the north is less cratered, because 3km of it was blown away into space and since then not so many new craters have been formed.

As a matter of co-incidence, some scientists predict this could have happened as early as 8500 years ago, about the same time the ice age was coming to an end here on Earth. Can't remember how they came up with that, I'll check.

Death comes quickly to old things.

</rambling on about something he can't put into words>

Ok, I'll tell you what it says, it says the world was created in six creative "days." "Days" could be any length of time, not just 24 hours.

Not to turn this into a Biblical debate, but I suggest you keep reading, Lobber. The Bible says ".. and the evening and the morning were the X day" signifying a 24 hour time period.

B-