This statement either comes from confusing Sakaar with the asteroid Fixit destroyed or the Planet Hulk Gladiator Guidebook, which gives data on the solar system Sakaar occupies. Sakaar has a listed equatorial diameter of 12,150. No unit is given, but as the whole guidebook is "translated" into English, I think we're to assume it is either miles or kilometers. Being 12,150 kilometers makes Sakaar ~600 kilometers smaller than Earth. However, if these are miles, it makes Sakaar ~4224 miles larger than Earth. This only makes Sakaar one and a half times larger than Earth, though, not 2 times.