The Fabric of the Cosmos - What is Space?

Very good explanations of spacetime/relativity, the Higgs field (before it's semi proven demonstration at CERN) and dark matter.

Via Occular Delusions who curate some very good content.

Space Time

So much is dependant on the velocity and vectors of space time as we perceive it. I was reading about meditation increasing the clock cycle of the brain and thus slowing time down ( I may have that the wrong way round) which is an insight into conciousness.

Dark Matter

One

This is the best I've seen yet (you generally know something is good on Youtube if it's under 50000 views and preferably under 5000). Sean Carroll is brilliantly lucid and engaging in this presentation.