If you're a science, physics, and technology buff like me, then you'll probably find these videos interesting. The first one with Galen Winsor would be where I'd start if you're not entirely into the heavier data and concepts that are in the following videos. If you think you have a good grasp on what radiation is, I encourage you to challenge your beliefs by watching this video.
NASA releases amazing images of deep space along with convoluted theories of the stuff space is made of. Stephen Crothers has become a favourite of mine. I like the cut of his jib, good sense of humour, even if it is rather corny at times. Very smart man. Listen to him challenge everything you have or may not have heard about black holes and the big bang universe.
Now, Bill Gaede is a great character! Entertaining, to say the least. He breaks down ideas that are often over looked and taken for granted. Definitions are important and he will show you have fundamental theories have run amuck because of it.
If you thought any of these videos interesting and you'd want me to share more, let me know!
Thanks for visiting!