( I recommend playing "Stay" by "Hans Zimmer" while reading this ;) )
The Ingame technology already exists to make this possible!
Just a Perfectly round planet, made with a black reflecting texture
So the goal of this would be to let it look like the Black Hole from Nolan's masterpiece "Interstellar" (This Clip also explains why a Black Hole should be Like a Sphere and not like a Disk :D) : https://www.youtube.com/watch?v=HUpwwdTCcs4
When Touching the Black hole or getting within a specific radius it teleports you to another solar system. The teleportation thing from the Jumpdrive could be usable for this.
-A good soundtrack
a good soundtrack that plays while you are near that black hole :D
and maybe not music but like sounds that play while near it just like the sounds of trees and birds that play while you are on earth.
So you Have the regular solar system maybe with gas giants or something and NO alien planets and In some way or another you explore space and find the black hole. You drive into it and get teleported to another solar system/galaxy/universe whatever. Maybe this world has a lot of different planets (Maybe take some of the community planets) including the Alien planet. You explore this universe and find out about the species that have lived there before. So the alien planet is no more in the normal solar system. Also there is a black hole to get back to the normal Universe.