On the west side of Otterswick Bay in Sanday, noted Walter Traill Dennison, and only visible with the the low spring tides – are the remains of many trees. And, he observed, Sanday folklore speaks of an old woman who asked the question: “What has become of the woods of Otterswick?” Associate Professor Scott Timpany of UHI Orkney has been studying pollen and plant macrofossils from the site, to build up a picture of an ancient forest and the probable date when it was drowned by the sea.

Old people in Orkney told George Marwick of Yesnaby, born in 1836, that they heard the shuffling feet of the dancers in the sky. But with the Northern Lights over 80 kilometres above us, few scientists believed it. It was only in 2012 that a researcher recorded the sound, and mechanisms are still unclear. Dr David Kerridge, who for many years led the British Geological Survey’s earth magnetism research, discusses the evidence for auroral sounds and describes the current understanding of how the aurora is created.

When Assiepattle slew the Stoor Worm, its teeth became the Orkney, Shetland and Faroe islands. Its body became Iceland – where its liver, set alight by a blazing peat, still burns today. How do Icelanders feel about their origin, and do they share the same fireside stories that Walter Traill Dennison recorded in Sanday of mermaids and selkies? Tom Muir introduces Prof. Terry Gunnell of the University of Iceland.

Orkney families have rich and varied traditions of their origins. Some say they're from a shipwreck – maybe a Spanish Armada vessel or the Crown, transporting Scottish Covenanter prisoners to the West Indies; or from a single survivor washed ashore. Others say they were settlers from Norway or servants of a Scottish earl – or escaping trouble in mainland Scotland. Dr Ragnhild Ljosland of UHI Orkney has been gathering up family origin legends and finding they build into a fascinating picture.