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Definitions

interplanetary space

[in-ter-plan-i-ter-ee spays] / ˌɪn tərˈplæn ɪˌtɛr i ˈspeɪs /
NOUN
deep space
Synonyms
WEAK
celestial spaces cosmic space cosmos intercosmic space intergalactic space interstellar space metagalactic space ocean of emptiness outer space region beyond Earth's solar system the heavens the universe the void the void above
NOUN
outer space
Synonyms
STRONGEST
cosmos
WEAK
celestial spaces cosmic space deep space empty space ether space infinite space infinity intercosmic space intergalactic space interstellar space metagalactic space ocean of emptiness pressureless space the heavens the void the void above

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Meanwhile, an interplanetary space race between the U.S.,

From The Wall Street Journal • Mar. 30, 2026

The fast solar wind -- a supersonic stream of charged particles -- originates mainly in the Sun's polar coronal holes and fills most of the heliosphere, shaping conditions in interplanetary space.

From Science Daily • Oct. 14, 2025

"Unlike the wind on Earth that circulates the globe, solar wind is ejected outward into interplanetary space," Chitta said.

From Reuters • Aug. 24, 2023

Solar sails have, of course, been built and successfully launched on proof-of-concept missions in both interplanetary space and low-Earth orbit.

From Scientific American • Aug. 23, 2022

It had been almost two years sailing through interplanetary space.

From "Cosmos" by Carl Sagan