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Fitting the evidence to the theory

Fitting the evidence to the theory - have been properly...

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Fitting the evidence to the theory The Gases that we find around bodies as we go out from the sun also seems to show trends that would fit with our general picture. Models of the equilibrium concentrations expected in a radial temperature gradient, given the nebula's initial composition, suggest that near the sun one would get a primarily CO and N 2 mixture as the most stable components. We would expect this to dominate in the early nebula inside the radius where the temperatures are above 680K. Below this (and hence further out) CH 4 and nitrogen would be the most stable combination, and then out beyond the point where the temperature drops to 330K ammonia and methane would be expected to dominate. Unfortunately this picture is drawn from models which assume equilibrium conditions, and as we discussed above, the 10 5 years we have for the material to settle to the final locations from the nebula may not hanebula may not have been enough for this equilibrium to
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Unformatted text preview: have been properly established. However, it does seem to fit in a crude way with the way volatiles and gases are distributed through the current system. Non-co-eval Theories Just for completeness we should note that there are also the non-co-eval theories of planetary formation. An example of these is the theory due to Woolfson, wheretwo molecular clouds, with protostars already forming or formed, meet head on, leading to turbulence and shock waves in both systems. These in turn lead to compression and condensation out of planetary bodies from the nebula: This model implies that a lone protostar retains its original angular momentum and would have no planets. Any lone star with planets must have captured them from a passing protostar by tidal forces. This "Tidal Capture Theory" can obviously take a number of varying forms, and there are several theories along these lines, though the nebulaic theories currently seem to be holding sway....
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