Hellish Vision of Mars Unveiled 144
mvladivostok writes "Yahoo has an interesting little article in which it is suggested that Mars may not have once been a warm, wet and hospitable planet that somehow lost its atmosphere; instead, it is suggested that the dead planet was occasionally bombarded by melting meteorites that carved out its distinctive craters and valleys. An interesting read."
Still (Score:5, Interesting)
Re:Still (Score:1, Funny)
Re:Still (Score:4, Funny)
Would you call people who want to keep Mars from changing either Reddies or Brownies?
Re:Still (Score:4, Informative)
Re:Still (Score:1, Troll)
Of course, in order to do that, you would have to institute an asteroid point defense system...
Re:Still (Score:3, Funny)
*ba dum!*
Re:Still (Score:2)
Seems a great place to build the Vogon fleet. But I guess that's highly improbable.
Re:Still (Score:1)
Oranges.:)
Re:Still (Score:2)
Re:Still (Score:1)
Why the gas escapes into space? Shouldn't the gravity of Mars keep the gasses in atmosphere?
Interesting... (Score:2, Funny)
Re:Interesting... (Score:1)
Whereupon they'll be sent packing back to Earth by Warner Bros. representative Marvin the Martian.
Re:Interesting... (Score:2)
Re:Interesting... (Score:2)
What? Not Doom 3? (Score:5, Funny)
Life on Mars? (Score:4, Interesting)
From the article:
If earth is anything to go by, I thought evolution of self-reproducing organisms would require quite a few million years and a primordial soup...
Re:Life on Mars? (Score:2, Interesting)
There has been a bit of discussion about this "interplanetary cross-pollination" lately. I'm to lazy to look for links, although there have been several slashdot topics posted.
Re:Life on Mars? (Score:3, Insightful)
True, but it's more likely to have happened the other way (assuming there was life on Mars). "interplanetary cross-pollination" from a small planet to a large planet is easier than the other way around. The escape velocity for the smaller planet is lower and the gravity well of the larger planet make it easier for the debris to "find".
Re:Life on Mars? (Score:1)
But would the likelihood not go back to favor Earth -> Mars because a rock from earth is much more likely to have life on it? Fewer rocks are ejected, but they have a much higher chance of harboring life. As opposed to more rocks that are mostly dead.
All of this is more or less a numbers game, like the Drake equation. I say we smash some large objects into the Earth and Mars and get some measurements.
Re:Life on Mars? (Score:2)
Probably, but if the conditions for life on earth and Mars were equally favorable when the solar system was younger, then it shifts to Mars.
Re:Life on Mars? (Score:2)
Re:Life on Mars? (Score:3, Insightful)
If earth is anything to go by
Why do people always want to assume that Earth is 'something to go by', i.e. that Earth is probably "representative of an average planet with life"? Its the only planet with life on that we know have, making it a sample of size 1, and as such we have absolutely no clue whatsoever where it would lie on any statistical curves. Earth could just as well be a statistical outlier in most things, for all we know. Making any assumptions about other planets, based on Earth, seems like a dicy process to me. Perhaps Earth has been really slow on the evolution scale, i.e. perhaps other planets required much less time for evolution to progress. Or it could be the other way round, perhaps it was really quick. Or perhaps it was just average. Or perhaps in other parts of the universe, other factors play bigger roles, such as 'seeding' of planets. Collectively, we don't yet have enough scientific knowledge and understanding of these processes to even begin to make proper "educated guesses".
Just because Earth is the only planet we've seen, does not mean we can make statistical assumptions about it. Nor can we extend such assumptions to other planets, such as Mars, because for all we know, Mars may also have been a statistical outlier.
like earth? (Score:4, Insightful)
Wait a minute, isn't that the same as earth and the rest of the planets? I mean, mercury doesn't get this kind of attention.
Re:like earth? (Score:2, Informative)
No, what they're saying is this: Earth has two basic kinds of geo-physical features, those caused by extraterrestrial effects such as meteor impacts, and those caused by terrestrial effects such as techtonic plate shifting or magma bursts as lava through volcanos.
The point here is that mainstream thought suggests that the craters/valleys were caused by water pooling/travel akin to that of earth, whereas this new model suggests that the craters/valleys were exclusively caused by the impacts. In such a system, you explain why the tributaries that are normally associated with water bodies aren't present on mars, along with several other problems.
Re:like earth? (Score:4, Funny)
Re:like earth? (Score:1)
Well, *I* envision the god of speed, running through the skies at night.
A bit contrived, perhaps? (Score:5, Interesting)
While it's certainly possible that Mars would have been bombarded this way, it doesn't appear likely for two reasons:
For one, there is no evidence of any other planetary body which would have gotten a significant infusion of water this way and it seems unlikely that Mars would have been the only target.
But the most important detail seems to be to just be a question of quantity. Regardless of maturity, in order for deep riverbeds such as appear on Mars to form you need a lot of water flowing for a fairly long time (years, not days). To get that water from impacts would mean that a LOT of such impacts need to have taken place over a (cosmologically) short period; which makes the first point above all the more noticable.
Even if Mars did get significant amounts of water this way (or had enough of it melted out by side effects) the water wouldn't have been around long enough to make geological constructs unless there was an atmosphere allowing it to remain liquid long enough to flow around for years.
I'm surprised someone at NASA would publish national-enquirer quality science like that. More likely, Yahoo misread the paper to extract the nice sounding bits.
-- MG
Re:A bit contrived, perhaps? (Score:5, Informative)
Re:A bit contrived, perhaps? (Score:5, Informative)
Discover ran a story about someone who thinks Earth is still being bombarded by smaller bodies like this -- it was a couple of years ago I think. He's regarded as a flake, but he's at least on the edges of the real scientific community.
Regardless of maturity, in order for deep riverbeds such as appear on Mars to form you need a lot of water flowing for a fairly long time (years, not days).
Ever hear of the Lake Missoula ice-age floods? Water from a penned-in glacial lake burst through ice dams several times, ripping up the northwestern US in colossal floods. The entire surface of eastern Washington state was formed through quite sudden flooding [opb.org]:
Imagine ripples like in a streambed, only on the scale of hillsides. It doesn't necessarily take years.
Not that I'm buying this idea, but it's not as outrageous as all that.
Re:A bit contrived, perhaps? (Score:3)
Consider for a momment that ice did impact and formed a large crator. Is it now hot enough to melt? I thought it was more likely that it would of turned to a vapor (atmosphere required again right?). Even if it does melt into water, where is it going to go? It's in a crator. It's got no where to run off too. Even if it did, it would be a race for it to run off versus the cooling action of space. Skip ahead a little bit. Now, we should see a crator with vast amounts of ice. Even it hadn't frozen completely at the time, surely the top would freeze quickly enough (like a frozen lake) to prevent it from running off somewhere.
After it's all said and done, I can't believe that such a thing was very probable. As such, seems much more likely that Mars had an atmosphere with rivers and some event happened which destroyed it (huge chunk of ice anyone?
Re:A bit contrived, perhaps? (Score:2)
Objects with the kind of mass the article is talking about are relatively rare now, but it is thought that they were abundant in hte early solar system. Over the billions of years, the planets have kind of swept up most of the debris that crosses their orbits. Nature likes a tidy orbital plane.
Re:A bit contrived, perhaps? (Score:2)
See what I saying?
Re:A bit contrived, perhaps? (Score:2)
If a bolide impact at the end of the Cretaceous can so alter the Earth's climate for long enough to drive an entire order to extinction (Dinosauria), then a similar impact on Mars could certainly give it liquid water for a few decades.
Re:A bit contrived, perhaps? (Score:1)
A snowball the size of Earth wouldn't have any perceptible affect on a gas giant the size of Jupiter. Saturn and Uranus could also be hit by large asteroids without leaving marks. We can't really see Venus to know if it's been hit.
Regardless of maturity, in order for deep riverbeds such as appear on Mars to form you need a lot of water flowing for a fairly long time (years, not days).
That's where you're wrong, or at least speculating wildly.
Did you read the whole article? (Score:1)
Also from the article: "Only during the brief years or decades after the impact events would Mars have been temperate..."
So they are saying that approximately 2 meters of rain fell per years for a period of ranging from years or decades. That sounds like "a lot of water flowing for a fairly long time (years, not days)."
Re:A bit contrived, perhaps? (Score:1)
Mars was tectonically active until relatively recently (perhaps less than 100 million years ago). Yet the article talks about impacts 3.5 billion years ago, continuing for less tha 0.5 billion years. Why have these not been obliterated by the more recent tectonics? And as I recall some of the canyons have eroded much more recent small impact craters, suggesting that free water has flowed much more recently.
Note also that 3.5. billion years ago is close to the formation of the planets. Planets form by the accretion of many such impacts, so this *is* a good explanation of how mars aquired it's water (and indeed all of it's mass).
But it is unlikely to account for subsequent melting and flow of that water, which is more likely to be due to 'weather' system (which implies an atmosphere), or subsequent melting by volcanic activity. The mechanism described in the article ceases c. 3 billion years ago, yet 'water-based' errosion processes have been occuring much more recently.
Re:A bit contrived, perhaps? (Score:2, Insightful)
Re:A bit contrived, perhaps? (Score:2)
>which would have gotten a significant infusion of water
>this way and it seems unlikely that Mars would have been the
>only target.
You must not have read the article, or at least you didn't read it carefully. The water wasn't all delivered by the bodies that collided with Mars - much of it would have already been in place, trapped as ice beneath the surface and at the poles (as we believe it is today). Furthermore, we have lots of evidence that water ice can be delivered to planets via comets - we actually watched comet Shoemaker-Levy 9 smash into Jupiter in 1994. That comet consisted of around 21 fragments, some with diameters of well over a mile, and had a visible impact even on that giant planet's atmosphere. You can visit this site [tamu.edu] to get an overview of the massive (and unexpected) results of their fiery plunge into Jupiter. Had it smacked Mars instead, it would have injected a vast amount of water vapor (and other gasses) into the thin Martian atmosphere, radically altering its composition.
Even today, if a large comet or even a sufficiently sized iceless asteroid slammed into the surface, it would produce a massive explosion, throw mountains worth of material into the atmosphere and generate a tremendous shockwave. The heat that would result from such events - including the rain of ejected rock falling back to the surface of Mars - could melt that subsurface permafrost on a global scale. Throw in any ice delivered by the impactor itself (for example, from a 20 mile wide comet) and you'd have one hell of a flood.
As CO2 and water vapor poured into the atmosphere, they'd rapidly insulate the planet, allowing still more ice to melt and resulting in colossal floods on a global scale. Another article I've seen on this theory points out the atmosphere could become hotter than a self-cleaning oven (more than 800 degrees Fahrenheit). This flooding could go on for years, until Mars cooled and its water vapor / CO2 atmosphere largely precipitated out, seeped through all the regolith at the surface, and refroze as a layer of permafrost.
Re:NASA and Disney, you mean (Score:5, Funny)
Down in the corner there was a standard disclaimer to the effect that if you found any inaccuracies in the map during use, NASA and the USGS weren't responsible.
Use?
Re: (Score:2)
and in one moment... (Score:2, Funny)
Oh yes, you can! (Score:1)
Before the bombardement there was no water on Mars, so the O2 factory was of no use.
The aliens must have built it after the bombardment!
Red Mars (Score:1)
3.85 billion years ago ... (Score:5, Interesting)
Re:3.85 billion years ago ... (Score:3, Insightful)
We're working on it, though...
speculating (Score:3, Insightful)
Re:speculating (Score:5, Insightful)
In that light this is an interesting article: personally I still think the atmospheric therories carry more wieght, but this is an interesting new way of asking the Mars question all the same.
Real advances are often the product of what someone in an earlier post refered to as "National Enquirer Science", which might more neutrally be called "thinking outside the box"
Re:speculating (Score:3, Insightful)
"The fact that some geniuses were laughed at does not imply that all who are laughed ate are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright brothers. But they also laughed at Bozo the Clown."
Just because the odd breakthrough comes from some really bizarre sounding theory, doesn't negate the fact that most crackpots are just that - crackpots.
Re:speculating (Score:1)
incidentally your argument works equally well the other way up: just because most crackpots are crackpots, doesn't negate the fact that breakthroughs are often made with really bizarre sounding theories.
I wonder, (Score:4, Interesting)
Re:I wonder, (Score:2, Informative)
Gravity per se has nothing to do with precipitation. However, if it affects the small dust particles then it can also affect the precipitation.
For instance on Earth the formation of water droplets would be practically impossible without small dust and ice particles in the atmosphere.
Re:I wonder, (Score:2)
Could you post a simple explanation of how the size of raindrops is determined?
Re:I wonder, (Score:1)
Sure the gravity affects the terminal velocity as well as does the density of the atmosphere.
For a slow travelling particle, the terminal velocity is linearly proportional to the gravity and inversily proportional to a "friction" coefficient which, obviously, depends on the viscosity of the atmosphere. I do not know how exactly the viscosity/friction depends on the pressure (gas density) but I would expect the dependence to be rather weak (in a pressure range of 0 - 1 earth atm). Hence, the gravity would dominate the terminal velocity and, since the gravity on Mars is less than on Earth, the droplet terminal velocity would be less on Mars.
All this is, however, complicated by the final size of the raindrop as both the friction and the gravity pull depend on it.
The size of the raindrops is determined by the water vapor pressure inside the drop and outside it: How much energy would be gained/lost by creating a water surface and taking water molecules out through the surface, out of the droplet into the gas phase or vice versa. If you do the calculation, it turns out that under the ambient conditions in Earth's atmosphere, nucleation of pure water is highly unlikely. Evaporation of water molecules into the gas phase is energetically way too favourable in comparison with the forming of a water surface with surface tension. However, mix a nucleation center such as a dust particle, the coalescing of the molecules becomes much much easier.
Re:I wonder, (Score:1)
Re:Primitive? (Score:1, Funny)
Atmosphere (Score:3, Insightful)
Such objects tend to burn up in the atmosphere- and those which don't are rather uncommon, even geologically. What would be likely to make it through a thicker atmosphere?
I think this is a long shot, personally. It's a possibility- but for it to be a real possibility, this would have had to somehow occur before Mars had its atmosphere. Which is not impossible- far from it- but not particularly consistent with the data.
Admittedly, it's possible that the atmosphere was carried in a solid-frozen format on said bombardial objects, but that's even more of a stretch.
Re:Atmosphere (Score:1)
Re:Atmosphere (Score:1)
My point still stands, however. While it would explain Mars having more impacts than Earth, it wouldn't explain that many.
Re:Atmosphere (Score:3, Funny)
I'm not sure about that. Every time I play as Mars in SimEarth I always bombard the hell out of it immediately with at least 20 Ice Meteors to form an ocean.
Who's to say that the universe doesn't play SimEarth the same way that I do?
Re:Atmosphere (Score:3, Informative)
Re:Atmosphere (Score:1)
However, I still can't see as many objects as They seem to imply impacting with Mars. Space is not dense with objects, no matter what sci-fi movies may tell you.
Re:Atmosphere (Score:2)
Re:Atmosphere (Score:1)
Re:Atmosphere (Score:5, Informative)
Interesting. There's only one problem. You're incorrect. Mars' surface density is pretty close to the Earth's at 35000 meters. Roughly 0.015 kg/m3. Earth's at the surface (sea level) is approximately 1.2 kg/m3.
The martian figure is from Nasa (http://www.grc.nasa.gov/WWW/K-12/airplane/eqstat
and the Earth figure is from any standard atmosphere chart available on the web. I don't have my texts with me so I just grabbed the one off USA Today's site. (http://www.usatoday.com/weather/wstdatmo.htm)
Even if it were, Mars' atmosphere is much thinner and has a much lower pressure than Earth's. Meteors entering Mars' atmosphere stand a much better chance at reaching the surface than they would on Earth. Combined with the ambient atmospheric temperature of the planet's atmosphere, even the density wouldn't prevent this.
The equation of state for an ideal gas shows this relationship. (http://www.grc.nasa.gov/WWW/K-12/airplane/eqstat
"Admittedly, it's possible that the atmosphere was carried in a solid-frozen format on said bombardial objects, but that's even more of a stretch."
I have one word: "Comets" They are believed to be responsible for a large amount of the atmospheres of Venus, Earth, and Mars.
Anyway, just my $.02..
Daniel
Aerospace Engineering major
University of Central Florida - Orlando
Re:Atmosphere (Score:1)
True but, I claim, unimportant. Anything big enough to make a significant change to the Martian surface is big enough to get through the Earth's atmosphere and have interesting side effects when it lands here. A 10km body impacting the earth hardly notices the atmosphere.
Paul
Re:Atmosphere (Score:2)
>explanation for these formations- if a bit
>uncreative- it forgets the element of the
>atmosphere, which is the only reason Earth
>doesn't get pounded into rubble every meteor
>shower.
Eh? Did you read the article at all? We aren't talking about shooting stars here - we're talking about asteroids and comets that are miles across slamming into the planet. Objects that big wouldn't even notice the thin atmospheres of worlds like Mars and Earth. At the speeds they're traveling, they'd blow right through them in a couple of seconds and smash into the surface, releasing a tremendous amount of energy in the process and - if they're large enough - melting much of the subsurface permafrost on a world like Mars.
Your scientists are all wrong. (Score:3, Funny)
Spare me your "theories" of a harsh surface! If our democratically elected President believes we can breathe there, we can!
Re:Your scientists are all wrong. (Score:1)
Re:Your scientists are all wrong. (Score:1)
- Homer Simpson
Re:Your scientists are all wrong. (Score:1)
You do realize that it was Quayle that said that, right? [snopes.com]
Then again, you probably got that from an email forward, and nothing that's forwarded along is fake. I should know -- I earned a little girl $11.50 towards a kidney transplant by forwarding emails to everyone on my contact list!
Why dont we have concrete evidence? (Score:1)
Sometimes I feel we know a lot.
Juz sharing my thoughts guys..:-)
Misinterpreted article (Score:5, Informative)
For a better article head to the bbc website http://news.bbc.co.uk/1/hi/sci/tech/2546923.stm
The gist is that large impacts by asteroids or other bodies would heat water in subsurface ice, leading to massive flash flooding. They are speculating that very large impacts would have planet wide effects for short periods of time. This isn't that contrived, as there is evidence around small martian craters that suggest that ice has been melted leading to mud flows around the crater rim.
However, this doesn't explain why the northern hemisphere of mars looks like a dessicated ocean floor, which suggests a relatively long period of warm conditions.
Re:Misinterpreted article (Score:2, Interesting)
The impacts would have injected steam into the atmosphere, both melted from the surface and from the asteroids and meteors themselves.
That is, they suggest the warm conditions you mention were created by steam and hot water. And the source of the water would not only be ice on the planet, but also from the meteors. The flooding and stormy rains that would follow would no doubt be able to shape the surface of the planet, creating all the valleys and such.
And its significance now is? (Score:4, Interesting)
Thass nice. So what?
Well, it seems to me that if we begin to terraform Mars, or in fact, even build a base there that heats the surrounding area and spreads some moisture just by mistake, then we may get some sorta Martian kudzu [tbep.org] spreading everywhere. Sounds fine to me.
Rustin
Re:And its significance now is? (Score:1, Funny)
BBC version (Score:4, Informative)
a little nicer one the eyes in my opinion and has a picture too
Compelling (Score:1, Insightful)
hell on earth too (Score:3, Interesting)
Hellish Vision? (Score:1)
Re:Hellish Vision? (Score:2)
Which is ironic, considering Mission to Mars is widely regarded as a cure for insomnia.
Bullshit... (Score:1, Flamebait)
On a related story, the earth is NOT flat. Oh, and WE go around the SUN! Amazing, isn't it?
Re:Bullshit... (Score:3, Insightful)
Isn't that why the creationists are so annoying??? Because they can't make evolution fit with their preconceptions so its a lie?
Re:Bullshit... (Score:2)
That opposing "theory" usually involves people who walk on water, a globe covered in water with one little boat floating around, etc.
Most religious types don't like evolution because it forces them to realize that although there is a factual core to their religion, it is mostly stories. Stories. Back in the day, if you didn't understand something, it was attributed to God, demons, etc. Apart from the BSD devil, demons don't exist. Sickness is caused by GERMS, BACTERIA, etc. So don't bother with holly water, you need to visit your pharmacy.
When I see people start comming up with so many reasons why water doesn't exist on mars, chances are it is because they don't want to find life on other planets. That fact alone would discredit most religions on this planet.
Nothing wrong with religion. I was raised cathlic, and plan on a white church wedding (yum, honeymoon!). But to explain things, I turn to a page of science first, the bible dead last. And when I see scientists try to discredit water on mars, martian bacteria in rocks, etc, it is most of the time obvious that they are Sunday church goers to have to face their own fears that their religion is one big story, before they can let the science through.
This sounds reasonable to me (Score:1)
Asteroids sizes unlikey (Score:2, Insightful)
I cant believe this one. Especially if you look at our own impact craters. The Chixaclub crater in the Yucatan made rings 180 miles wide and the asteroid was estimated to be only 6 miles wide. Doesnt anyone think we'd notice the pothole left by a 150 mile wide asteroid? I would have to doubt there would be enough melt from teh asteroid or enough steam or water from the planet to wipe these out.
Maybe if these guys are feeling really adventuresome they can read about the Sudbury impact (hit Canada 1.8 billion years too early) and the Vredefort impact in central Africa. These two left similar impact crater sizes and theyre still noticible 2 billion years after they hit. We found Chixaclub underneath all that marsh and muck and its 65 million years old (gets credited for dinosaur extinction).
Re:Asteroids sizes unlikey (Score:3, Interesting)
>Doesnt anyone think we'd notice the pothole
>left by a 150 mile wide asteroid?
Please READ the article:
"Segura and colleagues used photographs of the Red Planet's surface and computer models to show that large asteroids or comets hit the planet 3.5 billion years ago."
That's 3.5 *billion* years. Almost any impact crater from 3.5 billion years ago on the surface of the Earth would have long ago been eroded away, uplifted by faults into mountains, or subducted down into the mantle. In any case, they'd be difficult or impossible to identify now. Very little of the Earth's surface from 3.5 billion years ago remains intact. On Mars, it's a completely different story.
There are a handful of large craters on Earth that are still identifiable after around 2 billion years, as this article [meteor.co.nz] makes clear. But the giants formed by large impactors from early in our solar system's history have long ago been erased (or at least thoroughly obscured) from the surface of this world.
Our moon on the other hand has plenty of gigantic impact scars left over from before 3.5 billion years ago. For example, the gigantic Imbrium crater on the lunar surface is around 700 miles in diameter, and was formed about 3.85 billion years ago. There are several lunar craters in excess of 500 miles in diameter. Our moon is also home to the largest known impact crater in the solar system, the colossal 1,300 mile wide South Pole-Aitken Basin [nasa.gov].
Re:Asteroids sizes unlikey (Score:1)
She also does say that she is making the assumption that the craters and river valleys are the same age. I would like to know if any of those river valleys are interupted by crater impacts, showing that some of them are newer, leading to this idea that it has happened many times. I doubt some of these incredibly deep valleys could be carved with even a millenia of 6 foot annual rainfalls. The Grand Canyon is small compared to some on Mars and it has been forming with a rather steady flow (remember the used to erode much quicker, when it was prone to sudden burts of water) for for five or six million years, a geologically young feature.
I still think Ms. Segura is missing some very important details when it comes to this theory.
Re:Asteroids sizes unlikey (Score:2)
The Grand Canyon wasn't carved by the explosive melting of permafrost encased in a layer of regolith, either. With that much sediment in suspension, who knows how long it might take to carve deep features, even in relatively hard rock. Similar events could have been commonplace on the early Earth as well, but all trace of them would have been erased by geologic forces on this planet's active surface.
You're also assuming the water carved all of the features we see today on Mars unaided. The problem with that assumption is that water would naturally flow through any existing cracks and low spots in the crust, ones that should have formed naturally as the planet cooled and its crust contracted.
I'd say this theory is by far the best yet for explaining how the surface of Mars came to look the way it does today. I certainly find it more plausible than the assertion that Mars was once warm, wet and earthlike, sporting vast oceans. Perhaps that was the case *very* early in its history, but once the surface began to cool the tiny planet was far too small to hold an appreciable atmosphere at that distance from the sun, particularly given how dim the sun was over 3.5 billion years ago. Lighter greenhouse gasses like methane would have quickly escaped into space, while heavier ones like water vapor would have frozen out at the poles. Eventually, the surface of the planet became so cold even CO2 started to freeze, and at that point it was all over for Mars.
Earth went through its own snowball phase at least once, perhaps several times during its evolution after its surface had finally cooled (a process that took far longer here than it did on tiny Mars, I might add). It apparently never became cold enough here for CO2 to freeze out of the atmosphere though, and Earth is massive enough to retain enough lighter greenhouse gasses (like methane) long enough for them to make a significant contribution toward warming the planet's surface. Eventually, that volcanic activity belched enough greenhouse gas into the atmosphere to free the oceans of their coat of ice. It didn't hurt that Earth was much closer to the sun than Mars either, or that by the time Earth was going through its big freeze, the sun was significantly brighter than it had been when Mars began to freeze over.
Quick geography lesson (Score:2)
Vredefort is in South Africa, which is nowhere near central Africa.
http://vredefortdome.co.za/ [vredefortdome.co.za]
Mars sounds familiar (Score:1)
Sounds like the condition of the streets where I live.
A Theory is a Theory (Score:1)
But you have to admit it's a well throught-out viewpoint, and contains no more hols than any of the other upproven Martian theories
Point is people, we all need to take this in stride. Start favoring one theory with no rational evidence, and suddenly you become religion. I personally don't care, I'd rather hear what scientests have to say WHEN they land on Mars ( hopefully within my lifetime ). Until then, all we've got is pictures and a handful of samples.
Interesting place (Score:1)
An ocean on Mars? (Score:1)
There is convincing evidence that Mars once had an ENTIRE OCEAN covering most of the northern part of the planet, early-on during the period of extensive meteor bombardment. This theory was further substantiated using a sensitive altimeter onboard the Mars Global Surveyor. Just take a look at this map: (It speaks for itself!)
http://ltpwww.gsfc.nasa.gov/tharsis/shademap.html [nasa.gov] Pretty amazing, eh?
I am aware that there is considerable debate on the matter, but I haven't seen convincing evidence that could explain the lack of cratering and extremely flat terrain of this northern region. Perhaps someone here who knows more about planetary science than I could provide possible explanations?
The true story. (Score:3, Funny)
Phobos to blame ...... (Score:1)
-- Everyone knows that Death Stars were the biggest destroyers of planets, UNTIL the crew of the 'Dark Star' set off on their twenty-year mission of unstable planet destruction.------
CORRECTED VERSION of MARS' HISTORY:
Does anyone recall the fact that the mass of Phobos is TOO low for it to be a solid body?
Now think, if Long, long ago in a galaxy far, far away the Empire built a THIRD Death-star but had to hide it because Luke and Hans kept blowing those things up
then, when they thought it was safe to use it - no one remembered where they put it?!
and of course, the skeleton crew manning it HAD to try out the BIG Weapon so they took a shot at the Fifth Planet - BAMM! Blown to asteroids, making the inhabitants of FOURTH Planet (where they had parked it in orbit ) extremely edgey!
(They had to run around for a time avoiding a fantastic large-scale meteor bombardment which caused a great deal of damage!)
"I hear a great tremour in the Force - as of a million voices crying out in fear and then, suddenly, nothing at all!"
"You're imagining things Luke!"
"Perhaps I am - it seems so far, far away - it would have to be in another galaxy infact."
So, the inhabitants of the FOURTH Planet transmitted an ultimatum to the crew of the orbitting THIRD Death-star - that they would have to allow an inspection of ALL Weapons-of-mass-destruction
"Or what?" asked the Death-star Crew.
"Or we'll strike your space-station with our Barsoom V3 Super-gun!" they answered!
So, what do YOU think happened millions of years ago?
They had a VERY BIG gun battle between the Planet-destroying Death Ray and the Barsoom V3 Super-gun
So what happened?
Well, it was an atmosphere blown off that planet and big pieces blown out of the Death-star
.