What would be the new clockwise?

[chakka35]

This may be an old chestnut; I have certainly thought about it for years:

If analogue clocks and watches, and all memory of them, disappeared, how would one define clockwise?
Unlike north, south, east and west which are absolute, clockwise is relative to the observer. If I rotate my hand in front of me in what is to me a clockwise direction it is anticlockwise to someone looking at me from the front. To a fly on the face of a clock the hands between him and the glass are going anticlockwise, and so on.

One definition is "the direction which the sun appears to take around the sky to an observer in the northern hemisphere looking south". Not exactly snappy. Or "the direction in which a normal screw is tightened". The word"normal" dilutes that one but is necessary to allow for left-handed screws.

Is there a natural object or phenomenon which moves in a circle and which can be viewed only from one direction? Something astronomical comes to mind, since it cn be viewed by us only from the earth. But what?

(Incidentally, have you noticed that , in the opening titles of Have I Got News For You?, the villain who is presumably supposed to be turning the pipeline off is actually turning it on?) chakka35 (Thu 16:54 28/Jan/10)

[bibblebub]

change the word from clockwise to sunwise then you have something snappy

[chakka35]

But only if you are looking south from the north, bibblebub.

[bibblebub]

(I would argue that the term clockwise also imposes certain conditions on the observer)

How about using something astronomical e.g. The Whirlpool Galaxy http://www.star.le.ac.uk/edu/Galaxies.shtml and you define clockwise as the rotation involved tracing each arm from the centre to the outwards

[rov1200]

I have no trouble when the radio announcer talks about the clockwise or anticlockwise direction on the M25.

[Old_Geezer]

That is because you imagine yourself looking down from above, rather than looking up from below.

But it shows one can define it by spining a top in a clockwise manner because no one is peering up from below at it.

[fredpuli47]

Have I Got News For You may be, unwittingly, right. Somebody answered this question on the BBC a while back.The answer was that (Russian) pipelines are turned off in the opposite direction to ordinary water taps.It's certainly true that the gas pipe connection on my calor gas supply here has a thread which runs 'left-handed' and the first time you think you're tightening it you're undoing it, and getting it connected in the beginning is a puzzle ; maybe the pipeline engineers abroad have extended the practice to the 'taps'.

[chakka35]

Thanks for that, fredpuli47. I am fascinated by the idea that the graphics cartoonist thought of checking the Russian version first. If he/she did, I'm impressed.

And thank you again, bibblebub. That is what I said and suggested in the first place. If that galaxy is the answer that's a good one. But is there something more everyday that can be as accessible as the clock is now?

[bibblebub]

There is a more absolute definition involving the motion of charged particles in magnetic fields (using the right-hand rule).

[Teleph0ne]

I think you need to get out more!!

[chakka35]

TelephOne, to whom is that boring cliche of a remark addressed?

[jake-the-peg]

Chirality (or handedness) is very interesting, firstly it is a sign of life.

Excuse this if you already know, but some chemicals have what are called isomers. These are reflections of each other for example look at this picture you should see that these are reflections of each other and not the same

http://www.elmhurst.e.../images/209mirror.gif

In chemical reactions you often get equal amounts of both types produced but in biological ones you only get one type.

This extends to DNA - if you imagine a clock face moving forward as it's minute hand goes around this is a left handed spiral, if its minute hand went back that would be right handed

(Most) DNA is right handed this could be your basis for a definition.

Ctd....

[jake-the-peg]

....

However this is a rather Eath specific definition.

It was for a long time thought that chirality was a symmetry of physics, that the laws of physics were the same for left handed as right handed.

However in 1957 it was demonstrated that some radioactive decays under a magnetic field occur with a predominant handedness.

http://universe-review.ca/I15-31-parity.jpg

In this picture a cobalt atom in a magnetic field emits fewer beta rays in the direction of the field than against it with a certain spin

This gives you a definition of left and right handed spin good for the entire Universe

It may be a bit obtuse but as I say it was only discovered 50 years ago ( and the discoverers got Nobel prizes ) It was damn hard to find - and important because it shows that deep down the Universe does care whether or not you are right or left handed

[vascop]

Imagine you're at the north pole or the south pole and that the pole is literally sticking up out of the ground. If you walk round it keeping it on your right you are going in a clockwise direction and vice versa. You could call them the "right-pole" direction and the left-pole direction.

[chakka35]

That's very good, vascop. But the pole doesn't need to be either Pole, so to speak. If I walk around any object in my garden, keeping that object on my right, I will be moving clockwise.
Except, alas, to a worm looking up between my feet. So, as with so many other ideas, we would have to add "when seen from above".

[McMouse]

But to the worm the term "clockwise" would provide the wrong description.

[McMouse]

Unless qualified by "as viewed from above"

[chakka35]

That's what I said, McMouse.

[vascop]

But chakka that was always the case!. If you had a clock with a transparent face then somebody standing behind it would say that it was going in an anticlockwise direction.

[vascop]

Another example: Imagine a large sheet of transparent glass person A on one side and person B on the other side. If person A has a marker pen and draws a circle on the glass and puts an arrow on it pointing in the clockwise direction, then person B will say that the arrow is pointing in the anticlockwise direction.
The only reason car's don't usually bump into each other is because right and left depend on which way you are travelling.

[chakka35]

Yes, vascop, that was the whole basis of my question: that clockwise is relative to the observer! All you have done is repeat it. Read my question again, please.

At the moment we define clockwise as the direction followed by the hands of a clock when viewed from the side where 3 is on the observer's right and 9 on his left. To make sure that we always see it that way we arrange for an opaque face behind the hands so that we can't see the hands from the other side.

Right.

So in an age without clocks how do we define clockwise in an equally ordinary, everyday way, accessible to all?