Re: Nature Article

From: Anders Sandberg (asa@nada.kth.se)
Date: Fri Aug 16 2002 - 04:05:09 MDT


On Fri, Aug 16, 2002 at 11:12:48AM +0200, Amara Graps wrote:
> Anders Sandberg:
> >Thanks. But what about finding the tangential component of the peculiar
> >velocity?
>
> Tangential with respect to what? To us? I had thought that your 'tangential'
> was my 'peculiar' velocity, i.e. that caused by the gravitational
> pull of their neighbor galaxy. I am assuming root-mean-square velocity
> for the peculiar velocity, then.

I was referring to the velocity perpendicular to the line connecting us
to the galaxy.

> Here:
> http://nedwww.ipac.caltech.edu/level5/March01/Strauss/Strauss6.html
> it says that 'only the radial component is what they can measure'.

Yes. They also discuss a cool method of estimating velocities from
assumed potentials and density fields.

Thanks, now I feel that I have learned something :-)

> This is a nice paper that should answer your question (I didn't
> read further, it's a long......)

Yummy!

-- 
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Anders Sandberg                                      Towards Ascension!
asa@nada.kth.se                            http://www.nada.kth.se/~asa/
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