History Main / TheMilkyWayIsTheOnlyWay

* ''VideoGame/{{Stellaris}}'' restricts everything to one galaxy, specifically due to the method of interstellar travel: hyperdrive can only proceed along "hyperspace lanes" between large stellar bodies, and none of these lanes travel outside the galaxy. Even late-game upgrades such as [[spoiler: the Jump Drive]], which tend to completely ignore hyperspace lanes, are still restricted to a maximum jump distance that is far less than intergalactic distances. [[spoiler: It ''is'' possible to travel outside the galaxy, however: the L-Gates will take you to a small star cluster that is explicitly shown to be outside the normal galaxy, if you manage to unlock them.]]

** [[BigGood Asgard]] themselves subvert this trope ''hard'', as Thor's ship was able to cross the distance between the Ida galaxy and the Milky Way in a matter of ''hours''.

* ''VideoGame/{{Stellaris}}'' restricts everything to one galaxy, specifically due to the method of interstellar travel: hyperdrive can only proceed along "hyperspace lanes" between large stellar bodies, and none of these lanes travel outside the galaxy. Even late-game upgrades such as [[spoiler: the Jump Drive]], which tend to completely ignore hyperspace lanes, are still restricted to a maximum jump distance that is far less than intergalactic distances. [[spoiler: It ''is'' possible to travel outside the galaxy, however: the Q-Gates will take you to a small "pocket galaxy" that is explicitly shown to be outside the normal galaxy, if you manage to unlock them.]]

Now, in RealLife, this is [[http://thatonewhojustis.wordpress.com/2013/03/24/extra-galactic-travel-is-harder-than-light-speed/ pretty realistic]]. The Milky Way is about 100,000 light-years across... but the nearest other spiral galaxy, Andromeda, is about 2.5 ''million'' light-years away, which is 25 times more for all you math-challenged types[[note]](there are "dwarf" galaxies in orbit around the Milky Way, and some are close enough that some of their stars are closer to Earth than the opposite end of the Milky Way is, but a work may treat them merely as extensions of the Milky Way since it took astronomers so long to realize they had their own center of gravity)[[/note]]. If your FTL drive takes 100 years from one edge of our galaxy to the opposite one while going full tilt, or your [[SubspaceOrHyperspace hyperspace]] shortcuts are limited by the need to return to realspace and assess your position after making a relatively short jump, then it is perfectly reasonable that you shouldn't be able to travel to another galaxy in a casual manner.

!Examples:

* In ''Website/OrionsArm'' a total lack of FTL has prevented anyone from leaving the Milky Way yet; indeed, the Terragen civilization mostly occupies the Orion Arm of the Milky Way galaxy alone, with some expansion into the neighboring Perseus and Sagittarius Arms as well. However a message from the Triangulum Galaxy has been picked up and massive telescope arrays have seen planetary scale building projects occurring in other galaxies. The Triangulum Transmission also told of a ten light-year wide object with the mass of ''billions'' of stars and made up of the artificially imploded remains of an entire galaxy headed toward the Local Group of galaxies. Not only is it crossing intergalactic space, it's also coming from an entirely different cluster of galaxies.

** The original trilogy and its associated materials is set in the Milky Way and [[spoiler:aside from the mechanical Reapers,]] none of the spacefaring civilizations in it are able to travel to other galaxies. This is because while the [[PortalNetwork Mass Relays]] which everyone uses to get around the galaxy allow instantaneous travel across hundreds to thousands of light-years, they are BlackBox technology, and not only does nobody know exactly how they work, a past BugWar has made TheFederation very cautious about activating relays without knowing where they lead. The limitations of non-Relay FTL technology are even starker; it's so slow in comparison (only 10 light-years a day, at best) that it takes forever to get anywhere, and your effective range is limited by the need to discharge the ship's drive every 48 hours on a planet or in a sufficiently powerful magnetosphere. More than 99% of the galaxy remains unexplored. All of this is a non-issue for [[spoiler:the Reapers]] given their immortality and vastly more advanced technology, and no explanation is given as to why they aren't interested in other galaxies.
** ''VideoGame/MassEffectAndromeda'' averts this trope, featuring an exploration party to the Andromeda Galaxy through going into stasis on a SleeperShip. Even traveling at the fastest possible speed the FTL drives could provide (and new tech to avoid the discharge problem), it still took the ships over 600 years to make the trip, and there is nothing in Andromeda that [[YouCantGoHomeAgain could possibly send them back again]].

** Finally explored in the ''Series/{{Ahsoka}}'' series. It turns out that [[SpaceWhale Purgills]] migrate between galaxies and the Jedi Order knew about this, as well as some of the hyperspace lanes that they used. This is also how the ancient Perdideans, more familiar as the Nightsisters of Dathomir, originally migrated from another galaxy to the main ''Star Wars'' galaxy. The reverse journey can in fact be accomplished using existing technology so long as one possesses the necessary navigational data and that the journey begin and end at the planets situated at the termini of the hyperspace lane connecting the two galaxies. Nightsister Morgan Elsbeth, has an enormous hyperspace ring constructed using seven salvaged hyperdrive engines from Super Star Destroyers. Massively-overpowered by the standards of most ships, it is capable of jumping far enough and fast enough to travel to the other galaxy.