
- Home
- Movies
- Best New
- Astronauts
- Features
- Collections
- Regions
- Past Favs
- Expedition 56 favs (6/4/18-10/4/18)
- Expedition 55 favs (3/1/18-6/3/18)
- Expedition 54 favs (12/15/17-2/28/18)
- Expedition 53 favs (9/12/17-12/14/17)
- Expedition 52 favs (6/3/17 - 9/11/17)
- Expedition 51 favs (4/10/17 - 6/2/17)
- Expedition 50 favs (10/30/16 - 4/9/17)
- Expedition 49 favs (9/6/16 - 10/29/16)
- Expedition 48 favs (6/19/16 - 9/6/16)
- Expedition 47 favs (3/2/16 - 6/18/16)
- Expedition 46 favs (12/11/15 - 3/1/16)
- Expedition 45 favs (09/11/15 - 12/22/15)
- Expedition 44 favs (06/11/15 - 09/11/15)
- Expedition 43 favs (03/11/15 - 06/11/15)
- Expedition 42 favs (11/10/14 - 03/11/15)
- Expedition 41 favs (09/10/14 - 11/10/14)
- Expedition 40 favs (05/13/14 - 09/10/14)
- Expedition 39 favs (03/10/14 - 05/13/14)
- Expedition 38 favs (11/10/13 - 03/10/14)
- Expedition 37 favs (09/10/13 - 11/10/13)
- Mystery Image Interactive
- Cupola Sim
- Overview Effect
- Dan Picks
- Search
- About
In Reid's compass experiment, why does the compass rotate one way, then another?

NOTE: This is a first guess at an answer. Maybe Reid can chime in with a REAL answer (!)
As shown in this illustration (credit Peter.reid@ed.ac.uk), the Earth's magnetic field loops into space. Reid's compass, which is mounted vertically, shows the curvature of these lines. When ISS is in the northern part of its path, the compass follows the lines of the curve, pointing mostly down. If it were directly over the north pole, it would point straight down.
The opposite effect takes place in the southern part of the ISS path.
And as it crosses the equator, the magnetic lines (and compass) are horizontal.
If you have a better explanation, send a note to us (see contact button above)
