Thanks for that reference. But the excerpt above doesn't explain what "Photophoresis" is.querious wrote:As much as I was looking forward to this mission finally proving or disproving that cometary jets are electrical discharge phenomena, it is now abundantly clear there are 2 things sublimating: water ice, and electric comet theory.Zyxzevn wrote:The water mantra is still going on..
http://www.esa.int/Our_Activities/Space ... -ice_cycle
They see the traces of water on the surface as evidence for water under the surface.
The model shows a cycle of heating the interior of the comet.
If their model is correct, then according to common physics the comet should soon explode.
Why are they so blind for the obvious electrochemical processes? (caused by sun's solar wind)
The only thing that was still puzzling to me was the "crystalline silicates" found in comets, but then I found this paper...
Hot temperature minerals have been detected in a large number of comets and were also identified in the samples of Comet Wild 2 that were returned by the Stardust mission. Meanwhile, observations of the distribution of hot minerals in young stellar systems suggest that these materials were produced in the inner part of the primordial nebula and have been transported outward in the formation zone of comets. We investigate the possibility that photophoresis provides a viable mechanism to transport high-temperature materials from the inner solar system to the regions in which the comets were forming. We use a grid of time-dependent disk models of the solar nebula to quantify the distance range at which hot minerals can be transported from the inner part of the disk toward its outer regions as a function of their size and density. The particles considered here are in the form of aggregates that presumably were assembled from hot mineral individual grains ranging down to submicron sizes and formed by condensation within the hottest portion of the solar nebula. Our particle-transport model includes the photophoresis, radiation pressure, and gas drag. .... Our simulations suggest that irrespective of the employed solar nebula model, photophoresis is a mechanism that can explain the presence of hot temperature minerals in the formation region of comets.
It is briefly explained below:
"Photophoresis effects in Protoplanetary Disks: a numerical approach
Nicolas Cuello 28 July 2014
Abstract @ http://www.ast.cam.ac.uk/talks/archive/3540
It is thought that planets form in the inner regions of protoplanetary disks (PPD) about 1-10 AU. However, the migration of solids, in some cases sending them in a very short time onto the star, is a problem for planet formation, known as the radial-drift barrier. It is crucial to overcome this major difficulty in order to build up planet cores next to the star. Several effects have been proposed to invert the radial drift of the planetesimals (magnetic breaking, dead-zones, meridional flow, turbulence, particle traps, etc...). In this work, we explore the star radiation effect on the inner regions of PPD, namely photophoresis. It is a very promising phenomenon which has been poorly explored from the numerical point of view. Based on recent experiments of Duermann, Wurm and Kuepper, photophoresis (i.e. the thermal creep induced by the star irradiation) seems a good candidate. Indeed, they showed that its effects could revert the inward motion of meter-sized planetesimals at 1 AU in the disk. By means of a semi-analytical model, it can be shown that this force depends on the total size of the grain and on its porosity. We include this effect in our two-fluid (gas+dust) SPH code in order to explore whether or not this effect can break the radial-drift barrier. We run a series of numerical simulations for various disk configurations and grain sizes to assess its impacts on dynamics and growth."
^^^^ Of course this mechanism for transport out to the alleged 1 LY distant "Oort Cloud" is only presumed. There are so many gaping flaws in this thinking that I don't even know where to begin listing them (not least of which is that nebular collapse is assumed a true event and that planetary cores overcome the alledged "the radial-drift barrier" and are then sent out from the star that formed via "collapse"--a contradictory and unaccounted for series of events).
First off (as I do know where to begin after all), why would tiny comets be singled out for this process--to then be transported 1 LY away? Such scrutiny reveals a leap of logic and reason.
Also, around the time of Stardust return sample analyses, some scientists proposed that the material may have been borne from "another star." What happened to that discussion?