The further down the theoretical rabbit hole you go, the more so even high-level discussions probably need a general comfort with the field.<p>Discussion about these soft particles, zero-energy photons and gravitons, being added to a vacuum changing its state out to infinity is pretty fascinating. I would have liked him to explain a little more in-depth how one of these particles could have no energy but still have a spin, though I imagine that&#x27;s left to the reader to go find the papers that define it.