North is up and South is down

**S.A.M.** · 07-07-07, 07:33 PM

Who decided the North pole is "up" and the South Pole is "down"; what is the history behind this convention?

**(Q)** · 07-07-07, 07:41 PM

Hmmm... I always thought the sky was up and the ground was down. Silly me. I'll stand on my head.

**S.A.M.** · 07-07-07, 07:43 PM

Originally Posted by (Q)

Hmmm... I always thought the sky was up and the ground was down. Silly me. I'll stand on my head.

If you're in Australia, you'll be the right way up.

**(Q)** · 07-07-07, 07:47 PM

Did you know that in General Relativity, we are all floating freely in space and the Earth is accelerating up towards us?

Can you picture two people standing on opposite sides of the Earth with the above in mind?

**S.A.M.** · 07-07-07, 07:50 PM

Originally Posted by (Q)

Did you know that in General Relativity, we are all floating freely in space and the Earth is accelerating up towards us?

Can you picture two people standing on opposite sides of the Earth with the above in mind?

What an interesting notion. So is our attraction to the earth a result of these accelerating forces upward toward us?

**(Q)** · 07-07-07, 07:52 PM

Originally Posted by S.A.M.

What an interesting notion. So is our attraction to the earth a result of these accelerating forces upward toward us?

Yup. Ever jump off a high diving board or on a trampoline. Do you "feel" any forces on you while in the air?

Better yet, have you ever sky dived?

**Oli** · 07-07-07, 07:56 PM

Originally Posted by S.A.M.

What an interesting notion. So is our attraction to the earth a result of these accelerating forces upward toward us?

In that particular case there is no attraction to the Earth, it's just accelerating towards us faster than we can get away.

**S.A.M.** · 07-07-07, 07:58 PM

Originally Posted by (Q)

Yup. Ever jump off a high diving board or on a trampoline. Do you "feel" any forces on you while in the air?

Better yet, have you ever sky dived?

Heh, sounds fascinating; unfortunately while diving from a 3 meter diving board a long time ago, I discovered that I suffer from unilateral vestibular system disturbances. This was aside from the fact that I lost my bikini top and sank like a stone so that I had to be rescued by a guy I had a semi-crush on (oooooh the humiliation), but it sort of soured me from sky diving and the like.

In this type of theory, what is the explanation for the gravitational attraction towards other objects (like moon, sun and whatever comes close enough to feel the pull)?

**S.A.M.** · 07-07-07, 08:01 PM

Originally Posted by Oli

In that particular case there is no attraction to the Earth, it's just accelerating towards us faster than we can get away.

I wish I'd paid more attention in physics class.

**Oli** · 07-07-07, 08:04 PM

Originally Posted by S.A.M.

I wish I'd paid more attention in physics class.

Looks like you had your mind on other things Saiyyadati...

Originally Posted by S.A.M.

I lost my bikini top and sank like a stone so that I had to be rescued by a guy I had a semi-crush on

**S.A.M.** · 07-07-07, 08:04 PM

Originally Posted by Oli

Looks like you had your mind on other things Saiyyadati...

Nah that was after physics class. Be serious Oli, I'm trying to make up for lost time here.

**Oli** · 07-07-07, 08:11 PM

In cartography, there are a variety of reasons. In fact, maps have been drawn in all sorts of fashion over the ages. During the Middle Ages in the Western World, maps were centered around Jerusalem as a spiritual center. Maps in many parts of the world were oriented according to sunrise and sunset also. Hence, East and West orientations. I ran across a blurb from a Usenet group that may prove interesting. My apologies, but I do not know the poster's name. Here is a link:
Geograph Usenet Archive

In reply to:

Try Peter Whitfield, "The Image of the World" (San Francisco:Pomegranate Art books, 1994. He has some interesting ideas "why things changed" North apparently becaome the preferred direction during the Renaissance in the fifteenth centuray, because: (1) the world map had to be widened withe the discoveries in the New World, (2) thus projection became of increasing importance, and (3) the first republication of Ptolemy in the west with reconstructions of his maps. In 1459 the world map of Father Mauro (p 33) had S at the top. In 1457 a Genoese World Map showed the influence of Ptolemy, twice the E-W direction than N-S and had N at top (p. 41) I don't know if there was an earlier N orientation in classical antiquity. Remember, NO maps from that time have survived, whatever maps of antiquity you have seen are reconstructions. Yours, Wolf

Interesting ideas there.

Of course, the "North Star" as a stable point in the heavens served as a common marker than everyone had access to. Look "up" and there it is. Glance at your map and start sailing. I would say that the Age of Sail cemented the use of "North" as an orientation direction for "up" on a map.

I am not sure of your question regarding referring to "North" as "up" in Astronomy. Unless, of course, you are referring to conventions that have been carried over from traditional mapmaking.

From: http://uplink.space.com/showflat.php...b=9&o=0&fpart=

And http://www.diversophy.com/maps/whatsupsouth.pdf

has some more information, including the interesting (and previously-unconsidered-by-me) fact the word orientation comes from "oriens" = East...

Be serious Oli, I'm trying to make up for lost time here.

Serious?
Moi?
You should know better than that.

**S.A.M.** · 07-07-07, 08:14 PM

Thats interesting. So it was during the renaissance?

Hmm and when we say North that is at the tip of the imaginary axis ?

Or not? (should've paid attention in geography too)

**Oli** · 07-07-07, 08:21 PM

Originally Posted by S.A.M.

Thats interesting. So it was during the renaissance?

Hmm and when we say North that is at the tip of the imaginary axis ?

Or not? (should've paid attention in geography too)

Well, since the Earth spins on a North-South axis it would only be logical to choose one or the other.
And most of civilisation (civilisation being defined as those nations doing the defining

) was North of the equator... they decided they were "up".

**S.A.M.** · 07-07-07, 08:30 PM

Originally Posted by Oli

Well, since the Earth spins on a North-South axis it would only be logical to choose one or the other.
And most of civilisation (civilisation being defined as those nations doing the defining

) was North of the equator... they decided they were "up".

But thats just convention isn't it? So we have a start and an end.

So does gravity work on air (gases) the same as it works on solids and liquids?

**Oli** · 07-08-07, 06:59 AM

Originally Posted by S.A.M.

But thats just convention isn't it? So we have a start and an end.

Of course it's just a convention.
There's no "reason" for it other than that everyone uses the same convention.
(Except my mother, who can never understand why somewhere we've just come from (if it's to the North), is marked as being ahead of us on a tourist map...

)

So does gravity work on air (gases) the same as it works on solids and liquids?

Yes.

**Baron Max** · 07-08-07, 07:07 AM

Originally Posted by S.A.M.

Who decided the North pole is "up" and the South Pole is "down"; what is the history behind this convention?

Cartographers did, Sam, ...the map makers.

Something had to be at the "top" of the map, didn't it?

And let's not forget that compasses point to the north, too.

Baron Max

**S.A.M.** · 07-08-07, 07:11 AM

Originally Posted by Baron Max

Cartographers did, Sam, ...the map makers.

Something had to be at the "top" of the map, didn't it?

And let's not forget that compasses point to the north, too.

Baron Max

Sure but if you're facing South, north is down on a compass, yes?