SFRPG

The forum for Science Fiction Role Playing Game inspiration and information! So Say We All!
It is currently Sat Oct 21, 2017 8:19 am

All times are UTC




Post new topic  Reply to topic  [ 4 posts ] 
Author Message
 Post subject: Which way is North?
PostPosted: Sat Apr 29, 2017 2:55 am 
Offline

Joined: Sun Sep 07, 2008 12:06 am
Posts: 360
So what determines North on a planet's magnetosphere?

If a word rotates opposite from Earth (relative to it's orbit) will north be determined by the direction of rotation? The direction of orbit? Some random property of the core?

_________________
I really love Classic Traveller, especially without the Imperium ... There, I said it.
Now pass me a laser carbine and a couple of extra battery clips.


Top
   
 Post subject: Re: Which way is North?
PostPosted: Sat Apr 29, 2017 3:14 am 
Offline
Administrator
User avatar

Joined: Thu Jul 03, 2008 1:22 am
Posts: 5294
There's "Geographic north". If you look at Earth from outside its orbit, you can define the geographic north pole as the axis around which the planet rotates in a counter-clockwise direction.

The Magnetic north pole is sometimes aligned to the rotational axis , and sometimes not - depending on the type of body. The Earth's is off by a few degrees, and it's been known to flip direction in the past - it's all down to the circulation of molten metal currents in the outer core that generate the field, which changes over time. Uranus' and Neptune's fields are way off, by 40+ degrees and are even not generated in the centre of the planet.

Which one you'd actually call "north" is probably down to the individual planet's society to decide :).

_________________
SFRPG Owner/Admin
This post (or any other post I made here) may not be quoted or copied beyond the SF RPG boards without my explicit permission.
Check out the latest news from Spica Publishing!
evildrganymede.net - visit the The Worldbuilding Hub, and check out my Science Blog!


Top
   
 Post subject: Re: Which way is North?
PostPosted: Mon May 01, 2017 2:15 am 
Offline
User avatar

Joined: Sun Jul 06, 2008 1:04 pm
Posts: 1032
Location: the Retirement Coast, NSW, Australia
North is on your left when you face East. East is the direction where the Sun rises. That makes the north the positive pole of rotation in a right-handed co-ordinate system; i.e. a planet rotates anti-clockwise around its axis as seen looking down from above its North pole.

On Earth, magnetic "North" has been sometimes in the North and sometimes in the South, with geomagnetic reversals occurring apparently at random on timescales of 100,000 to one million years, sometimes shorter. There doesn't seem to be any preference between the two magnetic polarities.

_________________
— Brett Evill

My SFRPG setting, Flat Black

© My posts to this board are copyright under the Berne Convention. They may be quoted on the board with appropriate attribution. They may not be reproduced beyond the board except with explicit permission from me.


Top
   
 Post subject: Re: Which way is North?
PostPosted: Mon Aug 28, 2017 2:34 pm 
Offline
User avatar

Joined: Tue Jul 08, 2008 8:42 pm
Posts: 2658
Location: Texas, USA
I believe that you can use Magnetic North as an indication of which direction is north - assuming the world has a magnetic pole near the rotational pole - which is most likely.

Also, you could use the rotational direction and the "Right Hand Rule". Wrap the fingers of your Right Hand in the direction of rotation and your thumb points towards North. Doesn't work for tidally locked worlds, but for most others it should - Uranus being the exception in the solar system.

_________________
My friends call me Richard. You can call me Sir.
www.XmasDragon.com


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 4 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Limited