View Full Version here: : Magnetic Fields May not Hold Atmospheres
22-03-2011, 07:45 AM
The idea that a planetary magnetic field being responsible for retention of atmospheres, is something I have always felt uncomfortable about.
So here's some good news about research which probes into this hypothesis ..
The importance of being magnetized (http://www.physorg.com/news/2011-03-importance-magnetized.html)
They go onto to compare the cases for Mars, Venus and Earth.
Its only my opinion (I have no evidence) but I have always felt the planetary field explanation to have been a 'weak' one.
Great to see scientists questioning the hypothesis, rather than blindly moving on assuming it is so !
22-03-2011, 09:48 AM
Strangeway goes on to hypothesise about 'neutral' atom loss form the atmosphere may be one explanation:
He concludes with:
Re-examine the geological evidence of liquid water on Mars, I say.
In my opinion, in the case of Mars, perhaps the erosion there was primarily caused by ablation/sublimation of CO2 and H2O ices, and Mars never had any liquid water to begin with .. that's going back to square one !
So far, we seem to skip through the quantum leap from observing formations on Mars, to immediately concluding that because they look like those we've seen on Earth, they must have been caused by the same process - ie: liquid water erosion. Hence large volumes of liquid water must have been present in Mars' past. Then we go pursuing the catastrophy theories centred around where did it all go ?
(IMHO, of course - but based on observation and reading).
22-03-2011, 10:25 AM
I can see a big issue at the bottom of all this:
If the planetary formation process is purely Chaotic, then the process is highly sensitive to the initial conditions. These conditions may end up determining the outcomes, which we observe today. And today, the outcome most obvious, across the Solar System, is the diversity of planetary environments within a comparatively tiny volume of space.
Monitoring the buildup of the extraordinary diversity of the environments we observe amongst the Solar System planets and then beyond to exo-environments, would then become a key scientific focus area.
If the count of planetary environment diversity starts to look like a bottomless pit, then our perspective on what it takes to get life started, (perhaps also a Chaotic process), may also be hugely broadened (ie: well beyond those we presently have).
If it takes way more environmental diversity than we currently imagine to get life started, then perhaps the common view that because the universe is so big, the chances of exo-life must be enormous, is vastly moderated. The rationale would be that maybe it takes a universe of the size we see, for one instance of life bearing environments to occur. And the alignment of diverse conditions, may just happen to occur rarely, in a given large volume of space. The particular alignment of the right initial conditions for life has happened at least once. Our problem is in trying to extrapolate from this instance without fully understanding the scale of numbers of non-life bearing environments, and then, the scale of of numbers of life-bearing environments. The parent population (the sum of the two) may just add up to what we presently see in our observable universe.
The more instances we see where things like planetary magnetic fields, perhaps not being the sole driver behind the presence of an atmosphere, the more we may start to emerge from what I feel may turn out to be a very narrow, myopic perspective of how life bearing environments may actually come into existence.
The perspective provided by Chaos Theory, suggests that many initially complex processes and elements spontaneously result in emergence of self-organisation, and that this emergence is sensitively dependent on the initial conditions, from amongst what might be a huge array of diverse environments.
The above thinking, (I believe), also fits in nicely with all the known Laws of Physics and Biological/Evolutionary processes. The only thing I can think of at the moment which stands in the way of this, is our present classical, fully deterministic thinking, inherited from our education systems and, perhaps, the classical physics eras.
At this is all in my humble, speculative opinion, of course - and discussion is most welcome. ;)
22-03-2011, 10:33 AM
Oh yes .. we also need to be very careful in our thinking about exactly which parts of our own planetary environment may or may not be sensitive to anthropogenic influence.
This is particularly important, if we are in the midst of an invisible (to us), long-term Chaotic process, sensitive only to the initial conditions.
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