The answer given in comment by hfsha-ga has some merit -
and is supported by this expert opinion:
(This may be opinion of the same person, of course)
but I think it does not fully answers your question.
There is some debate between the experts on the issue:
and the topic had to do with a profound issue of the
SEARCH TERM : Mach Principle
which was so far not fully resolved to universal satisfaction.
So - I will not give you a final, definitive answer, but I will comment on
(possible) meaning of the question itself:
The term 'angular momentum' is usually used on the context of
classical physics - as a vector in 3D space. Defind e.g. here:
This are two problems with answer given by hfshaw and others:
1) Vector quantity does not have a value. Only it's components
in some frame of reference have value. Meaning: if you are a man,
standing on the Earth, a spinning bullet passing by has a (non
zereo) angular momentum.
If you are a bug (or a microbe) sitting on that bullet , that same moment
The value depends on the frame of reference (aka coordinate system).
Hfshaw (and others) make an implicit assumption, that you are thinking of
certain 'preferred' system of coordinates, implied by today's accepted
(big bang) model of the universe - which is frame defined by microwave
background and by the stars - and then the answer is sort of a
with respect to the stars, the stars do not move (too much).
(This is ignoring the question of the 'missing mass' or 'dark mass'-
mass which is not visible (like stars) and is, according to some
making 90% of the total).
2) The second problem I see with glib answer to this question is that it shows
a 3D thinking, while cosmological theories are inherently 4D, and the
concept of angular momentum in relativistic (4D) theory is a topic for
a PhD thesis in itself.
The 3D thinking has some validity - since the big-bang moment defines
a special frame - in which there is e.g. universal time, but that
these do not have universal validity. There are (alternative) theories
which try to explain
red-shift (caused by expansion) by 'rotation of the whole universe' - however
the question 'rotation with respect to what' needs to be answered before the
concept of rotation has meaning - in relativistic (4D) universe.
So - in conclusion: your question is touching issues which are not
well defined and resolved. More simple questions: "For an observer on
- what is the angular momentum of our galaxy?" can be answered. The visible
stars clearly rotate around the Earth - and stars we see by naked eye are
in the Milky Way.
The questions about the whole universe, it's mass, energy, linear or
angular momentum, require either relativistic appoach, or an
assumption that one particular model (such as Big Bang) is valid, and
also that you specify a frame of reference. For the 'special frame of
reference implied by the Big-Bang' model - and assuming that the 'dark
mass' behaves -- well -
zero value is a good guess.
So - real answers is: no one really knows, as yet.
Request for Answer Clarification by
19 Nov 2004 01:09 PST
Hedgie-ga, thank you for the work, but in a sense the line of thinking
I was always interested in is more like racecar-ga's comment. This
was my argument with my professors that perhaps the argument that the
universe is isotropic is actually not really that strong.
I don't know if this is possible, if it isn't I'll accept the answer,
but can you tell me or conjecture if we did have a positive angular
momentum, what consequences would appear? For one there would be a
center of the universe, there would have to be... or there would have
to be an intertial reference frame for the whole and the whole
universe would have some kind of tails like galaxies do? Then the real
tricky thing for me to imagine would be that probably the curvature of
space would follow the outlines of this galaxy like structure?
The thing that makes this question a bit relevant is that afterall
most structure we see in the universe appears spinning around
Clarification of Answer by
19 Nov 2004 01:53 PST
To get a 'right' answer, one should disclose purpose and
if possible, motive when first asking the question. By default (that
is unless told otherwise) I assume that people ask about current
There are always alternative theories - and some are interesting:
and imaginative. For example guess that our universe is a black hole
or that we are part of computer model .. (I like the last one as
possible explanation of the QM weirdness :-)
One alternative theory, speculates that red shift of remote galaxies is caused
by rotation of the universe, not by expansion...
the SEARCH TERM "rotating universe"
brings quite a few such theories, some of them quite interesting.
However, as I said in the answer: Once you abandon (mainstream
Big-Bang model, which fits our 3D intuition) you need to think in
terms of General Relativity.
Your question, and racecar's remark, appear to be based on 3D concepts.
So I see an inherent conflict here. The question would have to be
formulated in 4D terms, before it can be seriously debated.
So answer is not 'NO' - but trather it is a different and even more
To get a feel of how 4D reasoning looks (and how much - or how little
can be explain without math) - please have a look at somewhat related