Its amazing to see this beast and think that all the firey stuff isn't the primary energy source (although totally necessary to pushing the mass out the back fast enough).

  The reason it’s very small is that almost all of the energy in hydrogen and oxygen is not stored in the chemical binding energy of these things going together.

  The vast majority of it is stored in just the rest mass energy of the protons and the neutrons, which chemical burning doesn’t affect at all.

[Edit note: Starship and Booster are methalox, yes. The physicist is talking generically, not about this launch specifically)