Last week James Cameron spoke at CalTech about Avatar, where he copped to all the compromises he had to make for the sake of entertainment. Talking about the floating mountains of Pandora, Cameron argued they might be possible thanks to magnetic fields, before admitting, “We figured that to actually lift mountains, the magnetic field would have to be strong enough to rip the hemoglobin out of your blood. But we decided not to go there.†So much for accuracy! Later, when Cameron was asked to explain how it’s possible that “most of Pandora’s fauna have a six-limb design while the Navi inexplicably evolved into a humanoid form,†he abashedly said he thought six limbs would really inhibit the actors’ performances. [Discovery]