Re: Riddle me this:
It was my understanding that its spacetime getting bigger
Everything is affected by spacetime so theres a good idea that we're expanding at the same rate as the rest of the universe (maybe that explains my waistline.. burp)
Hence the the 'big rip' idea for the end of the universe, where space time has expanded so far that the forces involved in keeping stuff together are less than the force of the expanding spacetime.
Hence gravity loses its grip starting with galaxy clusters, down to galaxies and star systems, planets, then electro-magnetism loses its grip, followed by the weak force then the strong force .. at which point protons and neutrons are torn apart.
Makes a better movie than a long slow heat death of the universe I think