Space Is Magic

Once you leave the surface of the Earth, all bets are off. What we think of as immutable laws of nature are merely local phenomena, and all manner of things unexplainable by anything we know are out there between the stars—planets identical to Earth in every way, elements that no one has ever suspected existed, chemical compounds that don't behave the way "our" science says they should, and creatures with powers that seem paranormal. Why? Because they're from outer space.

See: Applied Phlebotinum, Deus Ex Machina, Space Does Not Work That Way.

Subtropes:
 * Negative Space Wedgie
 * Planar Shockwave
 * Space Romans
 * Subspace or Hyperspace
 * Unknown Phenomenon

In science fiction, space is rarely deliberately magical, but rather ends up that way due to insufficient research, The Rule of Cool, or excessive handwaving. Thus it's better described by its related tropes. However, when fantasy ventures into the final frontier, space is literally magical. Natural law isn't just ignored; it's shown the door and told not to come back. It's entirely replaced by a Here be Dragons sign. This is typical for fantasy, but when it's applied to outer space, things can get...weird.

The changes in the laws of physics generally do not cause manned spacecraft or the humans aboard to malfunction, shut down, or fall apart. Such a spacecraft is usually contained in a bubble where earth science remains 99.9% reliable.

Film

 * In Highlander II the Quickening, perhaps in an inversion, aliens coming to Earth gain immortality (though they seem hugely long lived already) for as long as there's more than one of them.
 * Treasure Planet. So much that if you are an actual scientist, this movie will require Brain Bleach. In its defence, it's intentionally overstylized in this direction.

Literature

 * An aborted trilogy from Margaret Weis and Tracy Hickman made this explicit, with the rules of the universe changing radically in different areas of space. This left a human exploration ship in rather bad shape, as while it could navigate well near earth, if it entered the zone where, for example, a circle of magical statues is required for safety there would be trouble.
 * Pretty much everything H.P. Lovecraft wrote relied on this trope. Lovecraft was writing at around the time of Edwin Hubble's discoveries, which cemented the idea of other galaxies as large as the known universe of the time and gave people for the first time an idea of how large the universe was. Lovecraft said that all his fiction was based on the idea that the laws of nature only apply locally, and so his horrors from the stars were literally impossible for us to imagine.
 * The "Zones of Thought" series by Vernor Vinge plays with this trope, even though it is (on some levels at least) moderately hard sci-fi. The basic idea is that the laws of physics become more lax at increasing distances from a galactic core. In the "Unthinking Depths" at the center of a galaxy, not even thought is possible. The "Slow Zone" further from the core (where Earth is located) uses Mundane Dogmatic physics. In the "Beyond", still further away from the galactic core, more fantastic things like FTL and strong AI become possible, and in the "Transcend", beginning at the farthest edges of a galaxy and extending out into intergalactic space, Space Is Magic. The series basically uses the entire Mohs Scale of Science Fiction Hardness.

Live Action TV

 * Many episodes of Star Trek, from each incarnation of the franchise, treat outer space in this manner. Why do species that evolved on other planets have telepathic or even godlike powers? Because they're from space! How does the Negative Space Wedgie take over the minds of the crew, and how do the waterfalls on the paradise planet run backwards? They're in space, that's how!
 * Few sci-fi series better embody this trope than Farscape.

Tabletop Games

 * In the Spelljammer Dungeons & Dragons setting, the Greek philosophers were right. Each solar system is enclosed in an enormous crystal sphere, which has the stars embedded in its inner surface. Spaceships are frequently modified ocean faring vessels. Gravity is uniform; even the ships have an intrinsic gravitational field. The laws of reality within the spheres themselves are wildly variable, with some being geocentric, while others are Dyson Spheres populated by planet-sized megafauna. Space outside the spheres is a flammable substance called Phlogiston that allows for fast travel between the spheres.
 * Likewise, the Ravenloft setting is situated in "the Demiplane of Dread", which is a pocket dimension that serves as a prison for various Big Bads. Looking up in the sky you'd see stars, but in reality the entire realm is surrounded by a thick, endless mist.
 * In the Old World of Darkness, a spiritual analog to outer space is the Deep Umbra. It is home to spirits, monsters, insane mages, relatively sane mages, gods, weredragons, and Eldritch Abominations. Celestial bodies represent various metaphysical aspects, and you can visit their spirit-world mirrors. And because in Mage: The Ascension reality is consensual, some books indicate that deep space (beyond the local solar system and its nearest neighbours) is really a part of the Umbra, because humans have only imagined it.
 * GURPS Technomancer has this in a technobabbly way. Magic is caused by Oz particles, which were initially scarce on earth. (A nuclear test and a necromantic ritual later though...) However, it's been discovered that there are indeed oz particles in space, radiated by the sun, they just got blocked by the atmosphere along with the other harmful rays.
 * In Warhammer 40,000, space is definitely magical. This is unfortunate, given what it spawns.

Video Games

 * In the Warcraft franchise the space itself (thought it's called the Great Dark Beyond) is quite normal and unmagical, but it exists beside an alternate dimension called the Twisting Nether, a space filled with chaotic magics. Since distances are significantly shorter within the Nether, all teleportation and portal magic works by short-cutting through it. The bad thing is that demons originate from the Nether and the magics required to warp through it are addictive and slightly corrupting. Certain more mystical races such as the Titans choose to instead travel through space.
 * Cosmology in The Elder Scrolls universe is a little weird. For example, the two moons of Nirn are actually the physical corpse of a dead god. And other planets are projections of Alternate Dimensions owned by the Aedra and Daedra puncturing through a murky region known as the Oblivion in which everything floats. Stars and the formal sun are other punctures in Oblivion but project into the Aetherius. Also, the Serpent constellation moves around the sky without rhyme or reason and is said to be made of "unstars." Yeah.