PBS
When Time Breaks Down
Some define time by motion, but how exactly does this work? Space Time added a video as part of its The Origin of Matter and Time playlist to explore just this question. It breaks down the relationships between matter, motion, and time....
PBS
When Insects First Flew
Insects developed wings and the ability to fly earlier than any other animal—when exactly did that happen? Scientists know this fact but struggle to explain when insect wings developed and how this entirely new structure appeared. PBS...