We spend a lot of time asking whether ghosts exist. But perhaps there's a more important question we should be asking first.

What actually IS a ghost?

Is it the spirit of someone who's died? A memory trapped in a building? Some form of energy? Or could the explanation lie in the extraordinary workings of the human brain?

This week on It's A Small World!, Tanya and Mich explore the theories, science and strange questions surrounding one of humanity's oldest mysteries.

From intelligent hauntings and poltergeists to the Stone Tape theory, sleep paralysis and the psychology behind paranormal experiences, we're looking at what people might really be seeing, hearing and feeling.

And we're asking some rather awkward questions along the way.

We also discuss ghost-hunting evidence, unexplained experiences and the bigger question of whether proving ghosts exist would actually prove there's life after death.

Are ghosts evidence of something beyond this life, or simply proof that there's still so much we don't understand?

Expect curious questions, a little scepticism, plenty of humour and probably more questions than answers.

Whether you're a believer, a sceptic or somewhere in between, join Tanya and Mich for another fascinating conversation about the unexplained.

And tell us: what do YOU think a ghost is?