Give us enough time to get clear out into the galaxy, he said.

All sorts of species are moving out into the galaxy.

"And because the planets were close they would have continued to press deeper into the galaxy."

Except that he'd not gone out into the galaxy, neither he nor Martha.

"Shall we give you the knowledge to rush out into the galaxy and cause chaos?"

The story starts 4 hundreds of years after humanity spread out into the galaxy.

M'Benga wanted to go out into the galaxy, not wait for it to come to him.

The implication is that over time, these clouds have formed into galaxies.

"I'm actually impressed you knew; my people aren't renowned for getting out into the great, wide galaxy all that much."

Humans like yourself moved into the galaxy a thousand years ago.