Unusal question. Just curious.

[Nightshift]

Which way does a compass point in space? (Lets assume your in a plastic space capsual with no metal around)

[drmorbius]

Galactic north?

[ving]

towards the nearest magnetic source of course :)

[sheeny]

It'll follow the local magnetic flux lines. Near each of the planets it will be dominated by the magnetic fields of those planets (whatever orientation that is). Within the solar system but away from the individual planets I guess the Sun's magnetic field will dominate. No idea how far out you have to go to get away from that or even how it behaves!

Al.

[Miaplacidus]

Well, at some point my hair will be rubbing on the plastic, so I reckon it will be pointing at my head.

[Nightshift]

You have all been a great help . . . . . NOT

Bugger it, I'm going to pack my GPS and leave the compass at home, that'll do. :screwy:

[IanW]

It depends!

First off, how far out in space are you talking about, low orbit? geostationary orbit, between the planets? or outside of the solar system? next to a star etc?

Next!

[Nightshift]

My thoughts were outer space, say, half way between home and Alpha centauri, what the heck lets say half way between our galaxy and the next.

[mickoking]

Our Galaxy has a magnetic field. I don't know where galactic magnetic north is?

[ballaratdragons]

My suggestion is 'throw away the Compass'. Pretty useless in space. It's like having a box of matches on the Moon. We know they work . . . But!

[mickoking]

Our Galaxies magnetic field is pretty weak (Earths=50 micro tesla, Milky Way=0.1 nano tesla) so I dont know if a compass would respond to it in intergalactic space? The galactic magnetic north is above the centre (core) of the Milky Way, probably somewhere in Opiuchus.

[Astroman]

come to think of it the GPS will be pretty damn usless out in space too. especially if your outside the area where they operate.

[Argonavis]

Good point, the MW magnetic field is but a smidgeon of the Earth's.

The Earth's magnetic field is generated by our fluid iron core that creates a fairly coherent field, acting like a "giant bar magnet" as the textbooks put it. The magnetic north is easily defined as the north pole of the "bar magnet".

The Galaxy does not have a giant fluid iron core so does not act like a bar magnet with a north pole.

I believe that, relative to the Earth's, the MW magnetic field is fairly messy. The magnetic field lines are marked by sychrotronic radiation generated by pulsars, neutron stars and active black holes, of which there are numerous discrete and dispersed sources, creating magnetic force lines all over the shop. There is also the primordial magnetic field created when the galaxy formed. This has magnetic field lines running along the spiral arms. Your compass may be pointing somewhere along the magnetic field lines, but I wouldn't think it would be our version of the galactic north pole, or anywhere else in particular.

A good example of a messy magnetic situation is the Sun, which has its magnetic field twisted and distorted by the flows of plasma and magnetic storms (sunspots) on the surface. You wouldn't know where you compass would point next if you were on the surface of the Sun. Even here, the magnetic field would be more coherent than that which exists for the whole Milky Way Galaxy.