General:
* Extraterrestrial: This is the most common and direct term. It literally means "outside of the Earth."
* Cosmic: This refers to the universe as a whole, including space and celestial objects.
* Celestial: This specifically refers to objects in the sky, like stars, planets, and moons.
* Extraneous: This refers to something that is irrelevant or extraneous to a particular situation, but can also be used to describe things that are external or outside.
More specific:
* Interstellar: This refers to events or objects that occur between stars.
* Interplanetary: This refers to events or objects that occur between planets.
* Lunar: This refers to events or objects related to the moon.
* Solar: This refers to events or objects related to the sun.
* Galactic: This refers to events or objects related to our galaxy, the Milky Way.
Other possibilities:
* Otherworldly: This describes something that seems mysterious, supernatural, or not of this world.
* Transcendent: This describes something that goes beyond the limits of ordinary experience.
The best word to use will depend on the specific context of your sentence.