Do all stars belong to a galaxy, or are there some stars which are orphans?
[We put this question to Carolin Crawford as part of the Planets and Cosmology show]
Carolin: Well certainly all the stars we know about do form in a galaxy but solitary stars would be very difficult to find.
Stars can leave a galaxy. Sometimes two galaxies merge, and in this process they can throw stars out into the vastness of space.
So there may well be lots of orphaned stars out there, but they are very difficult to find. All of the stars we know about are in galaxies.