direction of rotation?

[jajrussel]

Clockwise, counter clockwise in space seems to be a matter of position, so I am assuming that all things turn in the same direction in space, and that this direction is determined by the objects surroundings. An object rotates clockwise, or counter clockwise depending on my position, Therefore I'm in a sense seeing a mirror image of the forces acting on the object. Since the direction of rotation seems to be dependent on my position. I seem to need a more accurate definition of the direction of rotation. Down seems to be the best I can think of at the moment. Is there a better definition?

[Markus Hanke]

I am unsure what you are asking, to be honest.

In general terms though, a choice of direction is arbitrary only if the situation you find yourself in has a corresponding rotational or translational symmetry. For example, if you start off at the International Space Station and you go DOWN, then you will gain energy (free fall). But if you go UP, you need to invest energy (thrust). So these cases are distinguishable, and hence not equivalent. On the other hand, if you go around a perfectly round and featureless body that is not itself rotating, then which direction is “clockwise” and which one is “anti-clockwise” is a completely arbitrary label, since there is no physical difference at all (assuming there is not some outside point of reference).

[studiot]

The point is that clockwise v widdershins is part of a larger fact of life in the Physical universe.

You are right about the mirror.

Here is an interesting experiment with one.

Take a reasonable diameter bolt with a wing nut on it.
(I just tried this with an aerial clamp)
Hold it out level in front of you.

Now take the wing that is on the right and move it over to the left.

You should notice that this instruction is incompelte.

There are two ways to move it over.

After several rotations you should notice that one way makes the wingnut proceed forwards along the bolt.

The other way makes it move backwards.

 

That is why we we need our mathematics to distinguish the two directions of rotation, anddirection of travel of the screw forms the definition and distinction of clockwise and widdershins.
The choice is purely arbitrary.

 

However I mentioned this is part of a larger class of such phenomena, which are hugely important in Mathematical Physics.

Another simple example is that of the area of something.
An large number of physical phenomena a related to the line at right angles to the surface.

We choose the 'outward pointing normal' by convention as ther is another, equally valid one pointing inwards.
Or if you like, pointing outwards on the other side of the surface.

 

[swansont]

5 hours ago, jajrussel said:

Clockwise, counter clockwise in space seems to be a matter of position,

It depends on your choice of axes, not position.

5 hours ago, jajrussel said:

so I am assuming that all things turn in the same direction in space

No, they don't. 

 

[jajrussel]

30 minutes ago, swansont said:

It depends on your choice of axes, not position.

No, they don't. 

 

If I apply force doesn't an object always turn In the direction of the applied force? This was a question I asked myself when i agreed with your posistion that things don't always turn in the same direction in space.

When choseing an axis wouldn’t I be in effect be arranging my point of view?

Okay, I’m not meaning to create a trap that i can pounce on. I’m just trying to stay young by exercising my mind. For me it is like me thinking all i need do is lift weights and i will start to look like charles Atlas... Nope, it aint gonna happen. So Newton, and Eistiens intelect by my own acceptance may be beyond my abilities.

Originally, i was reading about how stars form. Then I was distracted by wondering why things spin. What came to mind was all mass vieing for a point singular. Since there is usually an uneven distribution of mass i surmized pherhaps this was the reason for the rotation. Which for my own best interest, and maybe everyone elses is probably where i shoud have taken a nap.

But then i asked, but why the direction they turn, and from there my thoughts got confusing until i decided that everything turns in the same direction. So, i am guessing that if i am wrong. I’m gonna have to decide whats best for my health? A little more mental exercise, or a nap?

I’m leaning toward a nap...zzzz...

Thanks for the replies...

[Markus Hanke]

36 minutes ago, jajrussel said:

Then I was distracted by wondering why things spin.

Because angular momentum is a conserved quantity. Stars form (roughly speaking) from dust accretion disks, which themselves rotate - this angular momentum has nowhere else to go, so if the disk becomes hot and dense enough, and the star forms, it must rotate too. The same with the planets when they form from the remnants of the disk. So it’s essentially due to conservation laws.

[swansont]

1 hour ago, jajrussel said:

If I apply force doesn't an object always turn In the direction of the applied force? This was a question I asked myself when i agreed with your posistion that things don't always turn in the same direction in space.

Things tend to turn that way, yes. (I can't think of any exceptions) But I don't see the connection to things turning in space. There are counter-examples. Venus basically rotates backwards, and Uranus rotates about 90º off from the sun, and there are dwarf planets that rotate "backwards" (retrograde), as well as some of their satellites — Triton has a retrograde orbit around Neptune, for example. Comets can be retrograde as well.

1 hour ago, jajrussel said:

When choseing an axis wouldn’t I be in effect be arranging my point of view?

Yes, but that's not the same thing as choosing your position.  

1 hour ago, jajrussel said:

 Originally, i was reading about how stars form. Then I was distracted by wondering why things spin.  

A starting point is that angular momentum is conserved as long as there is no external torque.

[Janus]

2 hours ago, jajrussel said:

Originally, i was reading about how stars form. Then I was distracted by wondering why things spin. What came to mind was all mass vieing for a point singular. Since there is usually an uneven distribution of mass i surmized pherhaps this was the reason for the rotation. Which for my own best interest, and maybe everyone elses is probably where i shoud have taken a nap.

 

Start with a large cloud of dust and gas.  It is a collection of particles with a random distribution of velocities, which also means a random distributions of angular velocities/momentum with regard to the center of the cloud. The Sum of all these individual angular momenta gives the net angular momentum of the cloud.  It would be a pretty rare coincidence if all canceled to to zero.   There is always going to be some net left over. this mean the cloud as a whole is going to have some net rotation about an axis. (even if it is not readily noticeable)  As the cloud contracts to form a star and its planets, in order to conserve this angular momentum, the rate of rotation must increase and it becomes more and more noticeable. 

So basically, objects rotate because the original individual motions of the particles it was formed from didn't exactly cancel each other out.