Wubbo Ockels at TEDxAmsterdam 2009

Time and gravity: In his mind-bending TEDxAmsterdam talk, Ockels explains how "time" is created by human beings, as a way our brains can make sense of gravity. The speed of light is constant, because it is made by us: it's the clock by which we have calibrated our existence. Based on this premise, Ockels proposes a new way to explore life in our galaxy.