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Planet formation

13 September 2014

At http://phys.org/print329463697.html … the question is, how do planets form? Okay, we have the mainstream model in which the idea is that dust from the remnants of supernova acretes into discs around young stars. Such dust is thus thought, over time, to clump together in order to form pieces as big as pebbles, and over time, into even bigger and bigger pieces that eventually gell into a planet size body. However, at the point the pebbles form the consensus view is not entirely sure just how they expand into bigger objects. An answer is suggested in a paper in the Monthly Notices of the Royal Astronomical Society (2014) 'Evidence for Large Grains in the star forming filament OMC-2/3' See also arxiv.org/abs/1408.5429

At http://phys.org/print329382985.html … is about the formation of the solar system – and an oddity. Rather, odd as far as models and simulations of the solar system are concerned. Mars is the oddity. It shouldn't be there. The fact it is there suggests there is something the matter with the models – but no, this is not what this story is about. The models are based on the consensus view and that is to be defended – until it becomes impossible to defend. For example, it is believed (their words) that Jupiter and Saturn formed before the rock planets – such as Earth and Mars. This is because they are thought to be almost entirely gaseous and so they must have scooped up the gas around the Sun before the latter blew it all away. The gas giants were able to hold on to the gas because of their immense gravity – it is claimed. Simulations of the early solar system always begin with this premise – perhaps that is why Mars comes out as an oddity.

It gets better as the model also incorporates the idea that water (as on the Earth in large amounts) originated in the outer solar system – hence the idea tha comets come from a hypothetical Oort Cloud. This region is supposed to be thick with icy objects which are occasionally kicked towards the inner solar system – the comets. This is why astrophysicists still insist comets contain lots of water ice – in spite of recent visits to comets that show them as rocky objects.

The evidence that mainstream theory may not be quite right is in the fact their models are unable to replicate the solar system as it is. The paper is published in Earth and Planetary Science Letters 392 (15) April 2014, Rebecca Fischer, Fred Csesla, 'Dynamics of the terrestrial planets from a large number of N-body simulations' – see also NASAs astrobiology web site at www.astrobio.net


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