NASA has said, the mysterious hexagon at Saturn's northern pole has changed colour from blue to gold. <br/><br/>The observation was made by Nasa's Cassini spacecraft, which has been exploring the sixth planet since 2004. <br/><br/>The change in colour is thought to be the result of seasonal changes on the planet.<br/><br/>The hexagon is essentially a rotating cloud pattern, its shape may originate as the result of large differences in the speeds of Saturn's winds.