TV-PG
S31 • E7 Nov 18, 2003 55m7.7
In this PBS "Nova" documentary, scientists discuss the bewildering causes and effects of the Earth's magnetic field, including the fact that the field appears to have weakened during the last few decades. A group of experts, including physicists and geologists, examine the individual elements that make up the field - from the molten core to the far reaches of space - in search of answers to these perplexing questions.
