Magnet Earth
Why do bacteria need a magnetic compass? How do crabs in a laboratory know the time of the tides? Why do homing pigeons sometimes get hopelessly lost? What do sharks and bees have in common? These are some of the mysteries that stem from the Earth's magnetic field.
We are all living on a giant magnet and it would be surprising if biological organisms were not affected by it in some way ... even humans. Precisely how is slowly becoming clear. But the earth's magnetism is not stable.
At irregular intervals it completely reverses so that compass needles point south. The fossil record shows that strange things happen at such reversals. The next one is long overdue and the strength of the field is fading fast.
Narrator PAUL VAUGHAN
Film editor GEOFFREY BOTTERILL Editor SIMON CAMPBELL-JONES
Written and produced by richard REISZ Preview: p 29