The second closest galaxy to Earth is the Sagittarius Dwarf Elliptical Galaxy, discovered in 1994, which is about 70,000 lightyears from us. Third are both the Large and Small Magellanic Clouds, which are approximately 163,000 and 200,000 lightyears from us, respectively.
Fourth closest to Earth, and perhaps best-known, is the Andromeda galaxy, which is about 2.5 million lightyears away. The Milky Way contains dark matter, so it is technically the larger of the two galaxies, but Andromeda is nearly as large. It’s predicted that in about 4 billion years, Andromeda and the Milky Way will collide, causing them to merge into a single mash-up galaxy of epic proportions. Bad news, though: “Grand Theft Auto VI” will still not have been released.
Given what we know about warp engines in “Star Trek,” let’s do some calculations. Luckily, resourceful Trekkies have constructed online warp speed calculators, so if we’re going by the warp gauge on “Star Trek: The Next Generation,” it would take a starship traveling at warp-9 approximately 1,648,663 years and three months to reach Andromeda. Heck, at warp-9, it would still take a vessel 16 and a half years just to reach the much-closer Canis Major Dwarf Galaxy.
The space between galaxies is called the warm-hot intergalactic medium, or WHIM, and it doesn’t contain a lot of stars. It contains … well, gas. The theories as to what’s out there are based on computer models and the behavior of various particles, but as stated in a handy rundown in Wired, “The WHIM is so hot that it ionizes hydrogen, stripping its single electron away. The result is a plasma of free protons and electrons that don’t absorb any light.”
Whatever’s out there, though, it sure ain’t stars, and it sure won’t contain the kinds of places where Starfleet vessels are used to stopping. “The Next Generation” crew would need to spend over a decade trekking through a big span of gassy nothingness to get to the friendly aliens on the other side.
