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Author Topic: How do I build an accurate galaxy simulator?  (Read 6660 times)

Offline CliffordK

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Re: How do I build an accurate galaxy simulator?
« Reply #25 on: 13/10/2013 23:42:14 »
One of the problems would be to find as much information as possible about every star.  Are all 300 Billion stars in the Milky Way classified by mass, velocity, direction, etc?  Are they all even distinguishable as discrete independent stars?

Doing even a single n2 calculation on 300 billion stars would be problematic. 

One, might be able, however, to do the calculation around various exemplars.  Say, one wished to calcuilate our sun's trajectory and mass interactions in relation to the other 300 billion stars.  This might be able to be reduced to an order-n calculation, and something one could calculate given the availability of the data.  Designed generally, one could pick other exemplars too, such as VY Canis Majoris, and then repeat the calculations around it (again an order-n calculation).

One could always choose some kind of a simplification such as choosing a smaller galaxy, or to consider imposing symmetry, so rather than calculating on 300 billion stars, perhaps choose a 1 degree sector, and do the calculation on 1 billion stars.  It still may be a n2 calculation, but on much fewer stars.  Also, doing the calculations on a certain sector of the Milky Way would help reduce the number of hidden stars.

If data errors are random, then they might average out to a large extent.  However, if there is a specific bias in the data errors, then the outcome could be off significantly.
 

Offline Pmb

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Re: How do I build an accurate galaxy simulator?
« Reply #26 on: 14/10/2013 00:55:18 »
One of the problems would be to find as much information as possible about every star.  Are all 300 Billion stars in the Milky Way classified by mass, velocity, direction, etc?  Are they all even distinguishable as discrete independent stars?
I sent him an PM and am hoping to get a reply to see what he's really looking for.

I recall him saying that he thought that using approximations in models which treated the stars more as a contiuum rather than a set of particles is what led scientists to believe in the existance of dark matter dark energy.
 

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Re: How do I build an accurate galaxy simulator?
« Reply #26 on: 14/10/2013 00:55:18 »

 

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