Earth has a blanket of air

An example of metaphor in popular science writing:

"…as the gas rushes out of the rocket exhaust it propels the rocket itself in the opposite direction – and this will continue as long as the gas keeps rushing out, and obviously there is no need to 'push against' a surrounding atmosphere, which is why our probes can function excellently when beyond the top of the Earth's blanket of air."

Patrick Moore

Moore, P. (1994). The Great Astronomical Revolution. 1534-1687 and the Space Age epilogue. Albion Publishing.