Anchor: Our world has what is for them a normal gravity, but because of our much higher gravitational potential, our atmosphere is too dense to support them comfortably over sustained periods.
Entailed: You world has the same type of gravity as them.
Contradiction: They can stay in our world indefinitely.
Contradiction: The children are fighting over a ball.
Contradiction: You can buy books, clothes, and cheese at the stalls here.
Contradiction: Pinker prohibited them from behaving like that ever again.
Contradiction: Cynics believe the government allows certain stories to get into the public to attract sympathy.