In reviewing the surface of Mars it appears that it has been pelted by numerous meteors and small asteroids. My initial question is; is it possible that the atmosphere of Mars at one time ceased to exist thus resulting in many hits of various sizes to the surface of the planet causing this visible damage/extinction? These missiles were unable to be burned up much as they are today on Earth. On another note, is it now possible that the atmosphere has "re-formed" and explains why there is a realtively thin one today? It is known that we are slowly destroying Earth's atmosphere, could we be heading in the same direction as fateful Mars?
It certainly is. Mars is about 11 percent of the mass of the Earth. It's escape velocity is a lot lower. The mass of its atmosphere would be roughly proportionate, It would be a lot easier for Mars to lose its atmosphere. The loss of the Martian atmosphere might coincide with an extinction event on Earth that took away some of Earth's atmosphere. It might be that giant life forms require, more than anything, enough air to breathe. Thus larger life forms died out and left smaller ones surviving.
It is unclear if the martian atmosphere was indeed much thicker, however the main points to remember is that the gravity of the planet is not enough to fully sustain the atmosphere, it is obvious that in past water flowed in abundance on the planet surface due to the presence of numerous of crevices that could not have been formed by just sand. However not to be optimistic, underneath the numerous meteorite impacts on the surface another layer of old meteorites is revealed underneath. Earth although is heading towards the Apocalyptical environment collapse...this will be unlike Mars...since Mars is much more bombarded by meteorites than Earth...perhaps Earth is to end up more like Venus. I am no optimist, but I hope by that time people will be able to travel on their own in-situ-ecosystem spaceships.
The idea of Mars slowly losing its atmosphere presumes that the atmosphere is not being continually replaced. The Earth has vulcanism that releases water, carbon dioxide, sulfur dioxide, and chlorine into the atmosphere. Venus has the kind of atmosphere that you would expect if internal forces kept replenishing it. Mars is the one planet that might have its atmosphere stripped away by forces that would leave the Earth relatively intact, like this supernova that some scientists think caused the Earth to be pelted with iron that was moving at about 3 percent of the speed of light. You've got to think that whatever embedded those iron particles in those tusks, if that iron was travelling that fast, it had a nasty effect on the atmosphere.
You need to learn a lot about astronomics in our solar system when it evolved over 4.5 billion years ago. Meteors and asteroids were the norm and reigned down everywhere. Look up at the Moon at night and you'll see the results.
All of your answers make sense, but my primary question is, can an atmosphere dissolve and then rebuild itself from the gasses, etc released from the planet? I was unaware that gravity played a role in containing and maintianing an atmosphere. If you have more information on this it would be appreciated.
A whole atmosphere will not dissolve into, say, oceans on a planet if that is what u are asking. Fractions of certain types of gases will. As for the second part, an atmosphere can certainly be created from outgassing.
A lot of nitrogen has been removed since earlier days in the same way that a lot of carbon dioxide has been removed from the earths atmosphere since about 400-500 million years ago. But the whole atmosphere will not be removed by any one process let alone dissolution.
>> can an atmosphere dissolve and then rebuild itself from the gasses, etc released from the planet? Atmospheric gases are constantly lost from Earth. Some gases are released by the planet others are "unnatural". If some of these are not regenerated on Earth then they would be lost forever. Water and methane are readily lost. IMO the planets are ejected from the Sun, then Venus is a prime example of a planet early in the degassing phase. Earth has been heavily modified, but given enough time it will become like Mars as Earth moves away from the Sun. Mars is being slowly but actively stripped of any atmosphere it has left by the solar wind and Jupiter's magnetic bloch wall. The planet Mars has expanded quite a lot which reduces its surface gravity, and I expect it will disintergrate (via the above process) and add to the asteroid belt. Earth next!
All rocky body's with significant atmosphere have been heavily modified over the course of their existense (meaning venus, earth, mars, titan) some for the better some for the worst. However mars is not going to break up because of Jupiter, it isn't going to break up at all. What ever formed the asteroid belt was proberly hinderd by Jupiter to form a single object but the asteroid belt has in total less mass then the moon, mars on the other hand has almost 8 times more mass then the moon. The clear example that low gravity doesn't result in in atmospheric loss, is offcourse titan, a moon with less surface gravity then our moon but with a more dense atmosphere then Earth. So the problem with preventing Mars atmosphere is proberly preventing in from cooking by the sun. So preventing this would take some sort of planetairy shield, that's not inpossible.
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No, as far as I know atmospheres do not undergo such large changes as "ceasing to exist then re-forming". Mars has (and has always had, to my knowledge) a thinner atmosphere than Earth. This atmosphere will burn up asteroids of a certain size or less, but no bigger than that. Hence the presence of only large craters. If there was no atmosphere then Mars would look more like the Moon, with hundreds of craters of every size. We aren't destroying Earths atmosphere, we are polluting it and making it less friendly to life. Its density, and capacity to burn up asteroids is unaffected EDIT: also, ignore URIs post. He's a crank.
I would like to note that the north pole of Mars has the least number of craters...is that an indication of thicker atmosphere, different asteroid trajectory (elliptical), or a surface cover up (due to dust devils and such...)?
