Kurzgesagt – In a Nutshell YouTube channel

Entertaining 10–15-minute animated videos on a wide variety of scientific topics—for example, Did the Future Already Happen? (which includes some brain-bending concepts about what “now” even means given that time passes differently for things moving at different speeds), We Traveled Back in Time, Now Physicists Are Angry (time travel both real and imagined), and This Black Hole Could Be Bigger Than the Universe (is our entire universe inside a black hole?).