Factual error: The premise for this episode has a major flaw: the only things that could shift the Earth's orbit significantly are a near passage of or a collision with an astronomical body of sufficient size to alter the course of a body weighing 6.6 sextillion tons - the mass of the Earth. Either event would cause sufficient disturbances that cities would probably not be left standing, nor would there be anyone left to stay in or flee from them. While the events of the episode are mostly a dream, the revelation is that the earth is actually moving away from the sun, not towards it, so the mistake applies regardless.
Suggested correction: The Earth's orbit moves outward and away from the Sun about 1.5cm every year. Eventually though the Earth will lose orbital energy and spiral into the Sun. Norma and the rest of Earth exist in a time when the planet has moved away from the Sun.
