[emphasis added]New computer visualization technology developed by the Harvard Initiative in Innovative Computing has helped astrophysicists understand that gravity plays a larger role than previously thought in deep space's vast, star-forming molecular clouds.
Excuse me; but the characteristic of "... hierarchical structure" and "regions within regions" is a well known electro-plasma dynamic often referred to as "self-organization". A characteristic noted by Erving Langmuir which also led to the predicted recognition by Hannes Alfven that astrophysical plasma would take on a hierarchical "cellular" nature.Previous technology, Goodman said, doesn't allow for careful consideration of what she described as "hierarchical" structure — essentially regions within regions — and would have obscured specific details in the molecular cloud, such as nested areas of varying density and a physical break from one area to another.
Note the vague, unspecified use of the word "turbulence". I would posit that gravity is not making any sort of "comeback" what so ever but that these simulations probably keep gravity in more of a proper perspective in relation to the still overwhelming forces of electricity and plasma which either aren't accounted for or are indirectly referenced using the word "turbulence". This article sounds like a software advertisement as opposed to anything new and original regarding the influence of gravity.These popular models, Kauffmann said, assume that most of the changes in the clouds come from turbulence and that it is only after turbulence pushes molecules close enough that gravity comes into play.
Once denser groupings of molecules are formed and gravity becomes a factor, they attract more and more particles until either something disrupts them or they have enough mass to collapse and form a star.
But it is the process up to the point where the dense groupings form that Goodman and colleagues examined. Their analysis shows that, rather than turbulence being the only significant force pushing these gas molecules around, their gravitational influence on each other is also significant. That finding means that existing models, which leave gravity out until very dense clumps have formed, would over-predict the rate of star formation in these clouds.
There is nothing wrong with computer simulations per se, just as long as they are not given the same clout as EXPERIMENTAL EVIDENCE.earls wrote:Computer simulations are an invaluable tool. While I do subscribe to the "garbage in, garbage out" doctrine, all too often computer simulations are quickly criticized or ignored. While the "results" of any computer simulations maybe as fictional as pixie dust, they provide a beautiful baseline to guide research.
[emphasis added]Re: Electricity and Plasma, from Micro to Macro and Beyond...
by ZeuZ on Mon Jun 30, 2008 3:03 pm
Plasma scaling is the most interesting aspect about plasma in my opinion. Thats how people get data about planets (or the suns) magnetic fields from using Terellas, a shame that most Terellas have been replaced with computer simulations that dont tend to show the effects that Birkeland and others achieved with actual experiments.
Users browsing this forum: No registered users and 7 guests