Short version, just to get something in here and not give too much up about HOW it works:
You can explore across galaxies.
Soul found, in addition to this, that you can spell/op across galaxies.
Walkthrough of exploring across galaxies, as requested by Pie:
- Go to map.
- Change the URL’s “galaxy=…” to the ID of another galaxy.
- Find a system with more than one unexplored planet.
- Mass explore unexplored planets.