Is the atmosphere of Mars reducing?

[indrek120]

Is the atmosphere of Mars still reducing today by the influence of the solar wind? Or is it now a balanced ?

 

[neilsox]

I don't think we know for sure. Mars looses oxygen and traces of other elements due to solar wind and to a much lesser extent due to meteorites, Mars gains atmosphere, due to outgassing from below the surface, and comet impacts. The average temperature may be increasing over the past century or more, which means volatiles escaping the ice caps = more atmosphere. A tiny gain occurs due to solar wind captured by Mars. These likely balance almost exactly in recent years, but small changes may shift the net total atmosphere. Do we even know if Earth is loosing or gaining atmosphere? Neil

 

[Shpaget]

It's the process that lasts billions of years. You shouldn't concern yourself about it. By the time it changes significantly there might not even be humans left to care about it.

 

[indrek120]

But isn´t it possible that Mars didnt lost its early atmosphere because of some catastrophe (comet impacts, the end of activity of magnetosphere) but it happened just because hydrodynamic escape occured?

 

[Saiph]

the atmospheric loss due to normal thermal escape for a planet the size of mars, and the position of mars (i.e. it's solar flux intake) would take tens of billions of years.

Now, if it didn't start with much atmosphere, it could have reached this state gradually, but evidence suggests a much thicker atmosphere.

So it isn't really likely.

 

[yevaud]

It's more than likely that all species that could be swept away have been and what remains would, as Saiph says, take many billions of years to slowly be swept away by the solar wind, even with the spotty geomagnetic field. So it's quasi-stable at this point in time, I'd say.

 

[3488]

Also when the core of Mars solidified to the point that it was no longer convecting / or that Mars once had a dual layered core like Mercury or Earth, but it solidified enough to become a single core, losing the convection in the process, resulting in the loss of the global magnetosphere, allowed the solar wind to start eroding it.

Also when volcanism waned considerably, atmospheric replenishment / maintainance ceased, so not only was it being eroded awy by the solar wind, it was not being maintained.

My hunch, is that the atmosphere of Mars is reducing & I suspect Mars will eventually turn into a Mercury or Moon type world, but has been correctly pointed out, this is a slooooooooooooooooooooooooooooooow process & the Sun will have most likely morphed into a red giant by this point.

The oxymoron is, that before Mars loses its atmosphere entirely, it may get a much denser temporary one as the remaining volatiles are driven off by the brighteneing Sun, only to be lost to space.

Andrew Brown.

 

[indrek120]

But what you think to be the most likely reason why Mars lost its original atmosphere?

 

[MeteorWayne]

2 factors. Lack of gravity. Lack of a magnetosphere.

that pretty much covers it.

 

[indrek120]

But if Mars lost its early thick atmosphere about 3.5 billion years ago as scientists think and planet itself is about 4.6 billion years old then how the loss of almost entire original atmosphere took only billion years if only reasons of loss where the lack of magnetosphere and lack of gravity? And now the loss is almost null and disappearance of its thin atmosphere would now take ten millions years.

 

[MeteorWayne]

Physics

 

[yevaud]

But what you think to be the most likely reason why Mars lost its original atmosphere?

I'll explain. This is fairly simple Planetary Science.

The possibility of a gasseous species (that's what Atmospheric Physics types refer to gasses as, "Species") being lost is determined by an escape velocity formula, as follows:

Where:

M Mass of the planet (kg)
r Planetary radius (m)
h Height of the exobase, use h = 0 if unknown (m)
L Luminosity of the star, sol: 3.86 x1026 (W)
Ro For a planet: Minimum orbital radius of the planet (m)
For a moon: Minimum orbital radius of the planet - Maximum orbital radius of the moon (m)

Full Explanation Here

 

[indrek120]

Were there enough hydrogen and other lighter atoms to cause such a giant loss of CO2 or were there so hot atmosphere which caused so intensive escape of CO2?

 

[yevaud]

The factors to take into account is the surface gravity, the average global temperature, the particular gasseous species, and the presence/absence of a geomagnetic field.

In the case of Mars, it would be a lack of a significant geomagnetic field to help retain the lighter species, and a low-ish surface G, which would lower each species' atmospheric escape velocity. A Billion or so years ago, when (if) Mars had a significantly denser atmosphere, it also had a higher average surface temperature, which increases molecular activity - again allowing various species to escape more easily.

 

[neilsox]

When carbon dioxide is decomposed by the solar wind, the lighter oxygen atoms would sometimes escape into space, Would the fact that free carbon is a solid reduce the probability of escape into space? If yes, the surface of Mars should be sprinkled with soot = carbon dust, unless carbon dioxide is rarely decomposed. When burning magnesium decomposes carbon dioxide, lots of soot is released. The magbesium oxide is white. Neil

 

[andrew_t1000]

Does this mean that talk of "terraforming" Mars is just pie in the sky?
Unless somehow a way to "reboot" Mars' magnetic field is found?
Say we did find a way to melt the polar caps, wouldn't the newly "generated" atmosphere be lost?
When ever I hear or read about someone waxing lyrical about terraforming Mars, thats the first thing that springs to mind.

With all the insane interest in nuclear power thats flying around these days, we could dump tons of waste into the Martian core, get a Martian "China syndrome" going.

 

[neilsox]

China syndrome is likely a serious exaggeration, The molten plutonium likely sinks into the soil about 30 feet instead of 3000 miles to reach the core of Mars. Our present technology suggest that we can not get the high level nuclear waste to the core of Mars and all of it would likely warm the core only about one degree for a few centuries. Even if we could heat the core of Mars to 1000 degrees c = 1832 f a much weaker magnetic field than Earth is likely. Induction heating is a possible way to heat the core of a planet, but the electric bill would exceed all the riches of Earth.
Mars settlers can likely survive the extra radiation long enough to have children at least half of the time, but the life expectancy may be half that in advanced Earth countries, unless they stay in radiation shelters most of the time.
There are numerous hurdles to complete the terraforming of Mars and the final results may be unsatisfactory in hundreds of ways. We can be sure of the engineering of hardly anything until we try, and the present cost says don't try until we are much richer and much smarter. Neil

 

[andrew_t1000]

China syndrome is likely a serious exaggeration, The molten plutonium likely sinks into the soil about 30 feet instead of 3000 miles to reach the core of Mars. Our present technology suggest that we can not get the high level nuclear waste to the core of Mars and all of it would likely warm the core only about one degree for a few centuries. Even if we could heat the core of Mars to 1000 degrees c = 1832 f a much weaker magnetic field than Earth is likely. Induction heating is a possible way to heat the core of a planet, but the electric bill would exceed all the riches of Earth.
Mars settlers can likely survive the extra radiation long enough to have children at least half of the time, but the life expectancy may be half that in advanced Earth countries, unless they stay in radiation shelters most of the time.
There are numerous hurdles to complete the terraforming of Mars and the final results may be unsatisfactory in hundreds of ways. We can be sure of the engineering of hardly anything until we try, and the present cost says don't try until we are much richer and much smarter. Neil

I was joking!
You know like "humour"?
My point was if, and I stress IF, an attempt at terraforming Mars was made, I would be worried that the atmosphere would be lost faster than the polar CO2 ice could be sublimed.

My China Syndrome quip was a poke at the current squawking about nuclear energy being the saviour of the planet!

You might wanna lighten up!