Talk:Relative direction

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This article claims that teh left and right brain differ in functions. I read on Wikipedia once that this is a myth. Juan Ponderas

Lateralization of brain function --J-Star 23:58, 11 March 2006 (UTC)

Contents

[edit] Inaccuracies

(Which I've tried to correct) Left and right can be defined precisely using Parity violation in Weak interactions. Of course, the *words* left and right are arbitrary. But nature cares about direction (or more to be more exact, helicity). The article also implicitly confuses *parity* invariance and *translational* invariance.

See this page for more information.

Amcfreely 02:00, 29 April 2006 (UTC)

[edit] Left & Right

I agree that most people are using right hand, therefore the parent teach their child to use a "Right" hand (it means correct) and to leave the other hand not be used, so the other hand is called left hand (a hand to be left). Furthermore, "Left" and "Right" did not simply mean the two direction as now we use, we should use "Left hand side" and "Right hand side" because people have been told whcih hand is right and which hand to be left.

"If you magnetize a sample of cobalt-60 atoms so that they spin counterclockwise around some axis, the beta radiation resulting from their nuclear decay will be directed opposite that axis. Since counterclockwise may be defined in terms of up, forward, and right, this experiment unambiguously differentiates left from right using only natural elements: If they were reversed, or the atoms spun clockwise, the radiation would follow the spin axis instead of being opposite to it."
Here's my question: If doing this experiment requires one to know what right is, how is this of any use, since left is merely the opposite of right? Right appears to be a given here, which seems to be what we want to define. I think that the only things that can be given are up and down, forward and backward, and a third axis, mutually orthogonal to these two, on which left and right lie. For all I know, the colbalt-60 thing does this, but if so, it is poorly explained.
Might it be beneficial to think in terms of vectors within dimensions here. If we use the definition of Up and Down discussed below, and replace a gravity well with either the strong, weak, or electromagnetic force, can the ambiguity between left and right be removed by defining each relative to up and down, or are left and right still arbitrary in three dimensions, but finite in four? Master at Arms 22:19, 7 August 2007 (UTC)
You need some starting point - the article is on relative direction, not absolute. If your starting point is right, then you don't need an experiment to tell you what left is. But up/down and forward/backward can still be tricky, so there's the right hand rule.
The vector cross product is used to define new directions in terms of given ones, in any number of dimensions. In three dimensions you need to define two to get the third. Potatoswatter 05:29, 8 August 2007 (UTC)
Woops, not in more than 3. Potatoswatter 05:35, 8 August 2007 (UTC)
Never heard the term "absolute direction". How can there be such a thing when all directions are relative? If there were such a thing as "absolute direction", would that not imply a center of this universe? I don't see the relevance of your reply. Master at Arms 15:57, 10 August 2007 (UTC)

[edit] Unexplainable

Is it true you cant explain left and right, you just go in circles? Like: left is not-right. left is west. right is like the shape L. (You always come back to needing a definition for left or right)

Yes, that is true. There is no universal explanation unless you start using observations of particle physics. The reason we call the directions "left and right" is simply because long ago, we decided to do so. These definitions have since been carried from generation to generation through word of mouth. --J-Star 07:59, 13 November 2006 (UTC)
I do not believe that this is true. The car diagram and its description in this article do unambiguously distinguish left from right, provided that one already understands that we are looking at the names for opposing relative lateral directions. 71.102.186.234 01:41, 20 November 2006 (UTC)

Deleted some fairly wierd vandalism in the car example.--70.157.78.223 01:24, 11 February 2007 (UTC)

[edit] rewrite

I rewrote a lot. Either the physics & math stuff is clearer now, or just more tortuously lengthy. Lemme know. Potatoswatter 10:02, 19 November 2006 (UTC)

[edit] Deleted unhelpful text

"In order to figure out which hand is which you will need a clock, a compass and the sun. Face the sun and check the compass. Before noon, the compass points to your left hand. After noon, it points to your right. If the compass points forward or backward, or the sun is directly overhead forcing you to lie down, take a nap and try again." Alex Law 09:36, 23 February 2007 (UTC)

Perhaps I was trying to be too humorous, but maybe it's better to fix it than remove it entirely? Elsewhere in the article it does promise to let you know which hand is which. Potatoswatter 16:46, 23 February 2007 (UTC)
Don't worry, it's fixed now. Improvements For All 07:06, 10 July 2007 (UTC)
Added clarification that the opposite is true in the southern hemisphere - you guys are always so hemispherist! P g chris (talk) 12:19, 20 January 2008 (UTC)

[edit] Up and Down

In one dimension, up and down are undefined / not applicable. In two dimensions, up and down are arbitrary. In three dimensions, up is a vector away from a gravity well, and down is a vector towards a gravity well. So in four dimensions, up is...? An interesting way to view time? Up a time line and down a time line as opposed to seeing time as linear and forward and backward? Master at Arms 21:52, 7 August 2007 (UTC)