* Astronomy

One of nature's greatest mysteries may have been solved after scientists revealed a new theory on how salmon find their way home.
Every year, 20 million of them leave Scottish rivers and travel thousands of miles to Norway and Greenland to feed. Remarkably, they then return to Scotland, often to within 100 metres of where they were hatched, in a process that can take more than two years.
How salmon complete such voyages across sea and ocean without getting lost has baffled scientists for generations. But a new theory proposes that the fish use the earth's magnetic field to locate their origins in Scottish rivers.

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