What do you mean by worlds apart?

As different as heaven and hell.

There is a big difference

Far apart-far apart

Very different

totally different

differ in thousands of ways

be totally different

apart from each other

There is a big difference between the two.

an immeasurably vast difference

[Interpretation] Heaven and earth have one pole above and one pole below. The metaphor is very different.

[Quotations] Lu Xun's letter to Cao Jinghua: "The illustrations printed in the book are really different from those printed by the author."

A different world, a different world.

[Usage] Too formal; Become an object; Metaphors are very different.