[modest]

Originally Posted by paigetheoracle

That's very interesting - so are you saying that as something shrinks, it spins faster? If so, would water going down the plug hole be an equal analogy because I've noticed it seems to spin faster at the end, when it gets to gurgling stage.

Yes. A water particle or anything else moving with a whirlpool (free vortex) does conserve its angular momentum.

Angular momentum is here tangential velocity times radius from center of rotation:

L(angular momentum) = V(velocity) X R(radius from center)

Since angular momentum stays constant V and R are inversely proportional. As V gets bigger, R must get smaller and vice versa. This means water further from the hole is expected to have less velocity than closer water. This is consistent with water forming a whirlpool and the link above does a bit to explain that.

Originally Posted by paigetheoracle

Is there some connection then, between Quantam Mechanics ''spin' and larger bodies 'spin'

CraigD addressed this in the post preceding yours.

Originally Posted by paigetheoracle

Could this relate to all forms of reality and all forms of life? (Beaurocracy and anarchy) or am I jumping the gun with a theory of everything outlook? (Blasphemy! Heresy!...no, just wrong according to the evidence we have at present). Sorry if this seems a bit 'Strange Claims' area but I'm a layman trying to make sense of existence, not an astophysicist

I'm not sure where you're coming from here. Perhaps a thread in strange claims would be a better place to discuss such a proposition.

~modest

[Pluto]

G'day CraigD


I agree with what you say. You expalin it to the T.

the spin of quantum mechanical systems ("particle spin") possess several non-classical features and for such systems spin angular momentum cannot be associated with rotation but instead refers only to the presence of an 'angular momentum-like' property.

I was thinking along the lines of wave centres. Each part adds to the same direction spin.

[paigetheoracle]

Could the fact that heavenly bodies spin, be proof of the big bang? (Considering my observations and questions on this subject or has this already been thought of?).

[paigetheoracle]

Parkes radio telescope in Australia has discovered a pulsar wobbling on its axis, helping confirm Einsteins theory of gravity. Is it known what happens to a body in precession, in space? Does it react differently to a spinning top on Earth, which careers all over the place when spin is lost and if so why?
__________________

[CraigD]

Originally Posted by paigetheoracle

Could the fact that heavenly bodies spin, be proof of the big bang?

I don't think so.

Astronomical bodies and systems of bodies - planets, stars, stellar systems, galaxies, etc. - are predicted to spin by any theory that assumes classical and/or relativistic mechanics to be at least roughly accurate on astronomical scales. Every cosmological theory I've ever heard of - Big Bang theories, with and without inflation, steady state theories, etc. - assume this, so all predict that the universe should be moving about like it's observed to.

There are some subtle differences between different theories of mechanics precise predictions of various motions - for example, between a purely Newtonian and General Relativities predictions of the precession of the orbit of Mercury - but nothing as dramatic as a prediction that rotation and revolution, or their absence, should be much more or less common than observed.

One occasionally hears or reads very vague, speculative ideas along the lines of Mach's principle (which isn't really a scientific principle, but more of a philosophical guideline for speculation) in which the absence of large-scale spinning might have profound consequences - for example, the idea that if systems were not rotating relative to the universe as a whole, they'd not have their usual momentums - but to the best of my knowledge, no well developed theory makes such predictions, and as there's no practical way to experimentally test such predictions (how can you make the whole universe stop moving?), so the subject is mostly one of philosophical recreation, not rigorous science.

Originally Posted by paigetheoracle

Parkes radio telescope in Australia has discovered a pulsar wobbling on its axis, helping confirm Einsteins theory of gravity.

I think Paige is referring to the recently published study of the double pulsar PSR J0737-3039A/B (see this news thread).

Originally Posted by paigetheoracle

Is it known what happens to a body in precession, in space?

Though the detailed calculations are way above my head, yes, I believe this is pretty well-known and explained stuff.

Though we know that at some point, General Relativity will need to be radically revamped, because it doesn't include important known phenomena on very small scales, observations like these recent ones show that it continues to do very well on astronomical scales.

Originally Posted by paigetheoracle

Does it react differently to a spinning top on Earth, which careers all over the place when spin is lost and if so why?

Rotating pulsars behave differently than spinning toy tops, because they are subject to very different collections of forces. A pulsar has a very large mass and angular momentum relative to friction and external forces (such as the gravitation attraction of a nearby companion body), while a toy top has a small mass and angular momentum, is subject to the constant large forces of gravity, a tabletop or whatever is opposing gravity, and air and mechanical friction.

The “careening all over the place” Paige describes is, I think, less a description of a mechanical prediction, than of what's commonly called chaos. Very small differences in initial conditions - ie: the position and speed of the top when it's launched - result in large discrepencies in in its predicted behavior later on. Therefore, no matter how precisely we measure a toy top's initial state, it's practically impossible to predict its precise position and velocity later on. Many systems, not just rotating ones, exhibit chaotic behavior.


I’ve noticed a tendency for people to regard the spinning of heavenly bodies as unexpected and significant, rather than overwhelmingly likely and signifying only that likely outcomes are observed more often than unlikely ones. I think this is because, as with many physical phenomena, our intuitions are tuned to everyday phenomena on the surface of Earth. In our everyday experience, things set to spinning – a wheel on an axle, a stone on a patch of ice, etc. – quickly stop due to friction. In the high momentum, low friction domain of outer space, however, this intuition serves us false. Although there are many examples of actual friction and friction-like phenomena in space (such as the tidal locking of the Moon to always point the same hemisphere at Earth), the norm, in space, is for objects set to spinning to continue spinning for a long time.

[paigetheoracle]

Originally Posted by CraigD

I don't think so.

Astronomical bodies and systems of bodies - planets, stars, stellar systems, galaxies, etc. - are predicted to spin by any theory that assumes classical and/or relativistic mechanics to be at least roughly accurate on astronomical scales. Every cosmological theory I've ever heard of - Big Bang theories, with and without inflation, steady state theories, etc. - assume this, so all predict that the universe should be moving about like it's observed to.

There are some subtle differences between different theories of mechanics precise predictions of various motions - for example, between a purely Newtonian and General Relativities predictions of the precession of the orbit of Mercury - but nothing as dramatic as a prediction that rotation and revolution, or their absence, should be much more or less common than observed.

One occasionally hears or reads very vague, speculative ideas along the lines of Mach's principle (which isn't really a scientific principle, but more of a philosophical guideline for speculation) in which the absence of large-scale spinning might have profound consequences - for example, the idea that if systems were not rotating relative to the universe as a whole, they'd not have their usual momentums - but to the best of my knowledge, no well developed theory makes such predictions, and as there's no practical way to experimentally test such predictions (how can you make the whole universe stop moving?), so the subject is mostly one of philosophical recreation, not rigorous science.

I think Paige is referring to the recently published study of the double pulsar PSR J0737-3039A/B (see this news thread). Though the detailed calculations are way above my head, yes, I believe this is pretty well-known and explained stuff.

Though we know that at some point, General Relativity will need to be radically revamped, because it doesn't include important known phenomena on very small scales, observations like these recent ones show that it continues to do very well on astronomical scales.Rotating pulsars behave differently than spinning toy tops, because they are subject to very different collections of forces. A pulsar has a very large mass and angular momentum relative to friction and external forces (such as the gravitation attraction of a nearby companion body), while a toy top has a small mass and angular momentum, is subject to the constant large forces of gravity, a tabletop or whatever is opposing gravity, and air and mechanical friction.

The “careening all over the place” Paige describes is, I think, less a description of a mechanical prediction, than of what's commonly called chaos. Very small differences in initial conditions - ie: the position and speed of the top when it's launched - result in large discrepencies in in its predicted behavior later on. Therefore, no matter how precisely we measure a toy top's initial state, it's practically impossible to predict its precise position and velocity later on. Many systems, not just rotating ones, exhibit chaotic behavior.


I’ve noticed a tendency for people to regard the spinning of heavenly bodies as unexpected and significant, rather than overwhelmingly likely and signifying only that likely outcomes are observed more often than unlikely ones. I think this is because, as with many physical phenomena, our intuitions are tuned to everyday phenomena on the surface of Earth. In our everyday experience, things set to spinning – a wheel on an axle, a stone on a patch of ice, etc. – quickly stop due to friction. In the high momentum, low friction domain of outer space, however, this intuition serves us false. Although there are many examples of actual friction and friction-like phenomena in space (such as the tidal locking of the Moon to always point the same hemisphere at Earth), the norm, in space, is for objects set to spinning to continue spinning for a long time.

Excellent reply! Usually CraigD leaves himself open to attack by people like me (Well me in particular) but I believe this covers everything very well. I personally wouldn't expect things in space to behave like they do in space - hence the question. You mention chaos as the likely outcome of loss, of momentum and spin: It's a bit like saying that life without motion leads to and is death (chaos) as well, meaning to me at least that both systems couldn't exist without some kind of movement (hold their form). Does this tie in with Quantam Mechanics and the atom, even though the laws governing this level of reality is so different or should I be asking this in the physics forum?