A couple years ago I read two novellas/novels set in the same universe. The outer galaxy is united in a largely digital civilization. Anyone that tries to enter the galactic core mysteriously finds themselves turned around.
In the first one, two travellers from different planets meet at a hot rock passing between their two solar systems. The main character, while she is on the trip, her whole planet slows down so that they will only experience a few years subjectively like her, as is there custom. On the planet/rock they find an aquatic species. The heat is caused by them figuring out how to turn themselves into little quantum strings or something that can run simulations and produce energy. Most people are in the circle faction but some are spiral in and others are spiral out.
In the second one, two travellers are invited to the galactic core as a planet is found that has DNA on it. The story alternates between their investigations and strange tale of weird alien life. It turns out the aliens are the source of the DNA and they evolved in the galactic core. Realizing how much the core sucks, they vowed to always push away others who try to enter the core. Thus they are revealed to be the mysterious keepers of the core.