Scientists work out origins of gold

A group of British and Swiss scientists says it may have solved the mystery of where gold comes from.

The earth does not have the extremes of pressure and temperature needed to create such dense metals and calculations by the team back up a theory that they were formed before the creation of the planet.

It's believed the metals are a by-product of nuclear reactions triggered by collisions between super-dense old stars -- objects up to a million times heavier than earth, but measuring only a few miles across.

The explosions threw the gold, platinum and other dense metals into space, polluting the gas around them, which then cooled into stars and planets such as earth, encasing deposits of gold within them.

From the newsroom of the BBC World Service