Tap the Brain is now live on CosmOnline: http://www.cosmonline.co.uk/tap-brain. So why did I feel compelled, you will wonder, to field a question about spaceships? It turns out that the theory of relativity that one has to use to answer it is the same that one would use to understand some superconductors – see this post in the papers category for an example of recent research on that topic.