Photons do have mass, because energy has mass & photons carry energy. They have ...

		pja on Aug 10, 2021 \| parent \| context \| favorite \| on: How far could a spaceship go if we never ran out o... Photons do have mass, because energy has mass & photons carry energy. They have no rest mass, which is why they are usually described as massless, but this isn't the whole story!