Herschel - first light

In article ,
Antares 531 writes:
Almost all galaxies have this spiral shape.

That's quite an overstatement, as someone else already pointed out.
In the local universe, if you count only relatively massive galaxies,
spirals comprise a modest majority. The various kinds of dwarf
galaxies far outnumber massive ones, though, and virtually none of
those are spirals.

One recent paper on galaxy counts by morphology is at
http://xxx.lanl.gov/abs/0905.3825

Is this caused by something similar to the Coriolis effect we see
in storm systems here on our own planet?

Probably not. Galaxies have nothing akin to the systematic radial
motion that storm systems have. (Coriolis effect is what gives this
radial flow its azimuthal component.)

If so, could this be an indication of curved space?

If you mean a global curvature of space, no. The upper limits on
overall space curvature are so small that curvature must be utterly
trivial on the scale of a single galaxy.

If you mean "curved space" as in the general relativity view of
gravity, then yes, but that's an odd way to look at things. More
specifically, spiral arms are almost certainly a gravitational
effect, but there's no need to invoke GR at the relevant mass
densities and velocities. Ordinary Newtonian gravity should work
fine, and curved space isn't needed.

--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
(Please email your reply if you want to be sure I see it; include a
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On Jun 24, 8:18*pm, (Steve Willner) wrote:
In article ,
*Antares 531 writes:

If you mean a global curvature of space, no. *The upper limits on
overall space curvature are so small that curvature must be utterly
trivial on the scale of a single galaxy.

If you mean "curved space" as in the general relativity view of
gravity, then yes, but that's an odd way to look at things. *More
specifically, spiral arms are almost certainly a gravitational
effect, but there's no need to invoke GR at the relevant mass
densities and velocities. *Ordinary Newtonian gravity should work
fine, and curved space isn't needed.


Relativity is a question begging exercise that is long past is shelf
life,more of a toxic expansion of Newton's ideas by being completely
indifferent to geometry.Humanity can no longer afford that particular
indulgence and most here in sci.astro.amateur now have a fairly good
idea what Newton actually meant in terms of absolute/relative space
(retrogrades) and absolute/relative time (the Equation of Time.

An unwary questioner would beg the question as to what in space is
'curved' but they can spare themselves that nonsense by going to the
original reasoning for 'curving' space,a idea that is so laughable
that I left sci.relativity almost immediately -

" This conception is in itself not very satisfactory. It is still less
satisfactory because it leads to the result that the light emitted by
the stars and also individual stars of the stellar system are
perpetually passing out into infinite space, never to return, and
without ever again coming into interaction with other objects of
nature. Such a finite material universe would be destined to become
gradually but systematically impoverished."

http://www.bartleby.com/173/30.html

Any number of participants here can bring you up to speed on the
framehopping misadventure of Newton which constitutes his
idiosyncratic difference between absolute and relative space -

"For to the earth planetary motions appear sometimes direct, sometimes
stationary, nay, and sometimes retrograde. But from the sun they are
always seen direct,..." Newton

They can also tell you that your 'curved space' is basically the Ra/
Dec conventions based on projecting the Earth's geometry into space.

I wish people would quickly grow out of the miserable condition that
emerged after 1905 and get back to dealing with the matter in a proper
geometric way.I am effectively finished with that relativity thing
which amounts to a wordplay wrapped up in an astrological framework
and so should everyone else.Too much to do with modern imaging to
dwell of early 20th century indulgences that make no sense except to
people who have an addiction for a late 19th century science fiction
novel -

"Really this is what is meant by the Fourth Dimension, though some
people who talk about the Fourth Dimension do not know they mean it.
It is only another way of looking at Time"

http://www.bartelby.com/1000/1.html


--
Steve Willner * * * * * *Phone 617-495-7123 * *
Cambridge, MA 02138 USA * * * * * * * *
(Please email your reply if you want to be sure I see it; include a
valid Reply-To address to receive an acknowledgement. *Commercial
email may be sent to your ISP.)