This article contains spoiler for The Mandalorian season 3, episode 3.Coruscant isn't actually the center of the Star Wars galaxy - it's far more exotic. Viewers can be forgiven for thinking the city-planet of Coruscant is the center of the galaxy. It was the galactic capital for millennia, with the politics of an entire galaxy revolving around its senate. Certainly the people of Coruscant got used to thinking of themselves as the most significant beings, the ones who decided the fate of the galaxy. Even the Jedi Order chose to establish its main temple on Coruscant, symbolically supporting the view this planet was more important than any other. The Mandalorian season 3, episode 3 riffed on this, with Coruscant residents admitting to their egos.
Coruscant is not actually the center of the Star Wars galaxy map, though. It is indeed situated in the Galactic Core, a region of cosmic stability and economic prosperity; there are stable hyperlanes binding many of these worlds together, explaining their dominance. It's generally believed humanity evolved on Coruscant in Star Wars, spreading out into the stars, which explains why the Core Worlds are dominated by humans and the Mid and Outer Rim are inhabited by so many diverse species. Palpatine's regime was centered on the Galactic Core, and he deliberately set humans against aliens, Core against Rim. But even the Core Worlds do not lie at the heart of the galaxy.
A Black Hole Lies At The Center Of The Star Wars Galaxy
Like most (possibly all) spiral galaxies, a supermassive black hole sits at the center of the Star Wars galaxy. This black hole warps spacetime, creating a region known as the Deep Core that is almost as inaccessible as Star Wars' more famous Unknown Regions. Both the Empire and the Rebel Alliance managed to map hyperspace routes into the Deep Core, but the constantly-changing gravitic fields mean these routes wouldn't remain viable for long - perhaps only a few years, perhaps centuries. Only Force-sensitives are really safe exploring the Deep Core, using the Force to navigate (a skill known, appropriately enough, as "Skywalking").
What Canon Star Wars Planets From The Inner Core Have We Seen?
The Deep Core may be relatively inaccessible, but it has indeed appeared on-screen in Star Wars. In The Mandalorian season 2, Din Djarin traveled to the world Tython - a powerful vergence in the Force, site of one of the first Jedi Temples. Tython also appears in Doctor Aphra #40, in which the corrupt archaeologist Dr. Aphra led Darth Vader there to launch a trap in another sacred Jedi site. Hopefully Tython will be explored in greater detail going forward.
Another key world in the Deep Core was set up in a canon Star Wars fact file in Build the Millennium Falcon #36, published back in 2015. This canonized the Legends planet Byss, described as "a strange world with an eerie glow caused by its sun" that was of particular interest to Emperor Palpatine. It contained a nod to a race known as the Rakata, who originated from Byss in Legends, stating that "empires were forged within [the] fiery furnace" of the Deep Core. The Rakata were officially canonized in Andor, which contained an unexpected Easter egg to the ancient race of conquerors who spread out across the Star Wars galaxy - and who seem to have inspired the Sith empires.
Episodes of The Mandalorian release Wednesdays on Disney+.