Put simply, is the explanation for velocity-based time dilation toward the end of this video correct? http://www.iflscience.com/physics/t...-video-explaining-einsteins-theory-relativity Considering he won $400k in an international science video competition, you would hope the judges would know! I haven't been able to find this explanation elsewhere, though. Essentially, he says that the subatomic particles within our body travel at a fixed speed at or near the speed of light, and that any of the macroscopic processes we experience are dependent on the interactions of these subatomic particles. The more closely matter approaches light speed, the longer it takes those subatomic processes to happen (from the viewpoint of a stationary observer) because their speed relative to their macroscopic context is less great. Most explanations for SR seem to me to explain why we must infer that time dilation would be observed relative to velocity, rather than a mechanism by which it happens. We know that time dilation must occur because otherwise the math leads to nonsense or paradox, and experiments have proven to death that it happens, but that's different from this explanation telling us how. It's a bit like how 18th- and 19th-century thinkers were able to get pretty far in describing how we must infer positive and negative charges in electricity, but that's different from being able to specify the mechanisms we can now theorize with our understanding of electrons. The above explanation feels satisfying in this regard of mechanism, but it's absent from other articles or posts I've read, so is it consistent with current scientific consensus? Thanks for your attention! I suspect this question has come up before, but I didn't find it readily in the forum history.