Dr. Kaii wrote:
In fact it was but I agree we need a gentle reminder
Just to point something out. Not only should be procedurally generated but also generated considering there are integalactic stars in catalogue right now. For example HE 0437-5439
it's 200.000 ly from us (consider that the diameter of the Milky Way is around 120.000 ly), os consider ULAS J074417.48+253233.0
or ULAS J001535.72+015549.6
, that are respectively 770.000 ly and 890.000 ly away. ULAS J001535.72+015549.6
is in fact more than 7 milky way diameters away (I attached a picture from that distance and angle of the Milky Way using SE in the old forum but I can't find it again).
Another important thing is that these stars have motions that trace back to our galaxy, so they are all runaway stars that escaped the Milky Way. This imposes several conditions on the future representation on Space Engine. First of all, the farthest from a galaxy the older the star has to be. In fact it should be impossible to find O type stars too far from the galaxy in intergalactic space for example, since they live at max 6 million years (they become B type or die in a supernova explosion before that). There are hipervelocity stars with 1200 km/s speeds exiting the Milky Way (none are so massive as main sequence O type stars but we are going to make the calculations with that), like US 708
that is 62.000 ly away from Earth. Considering all of this the maximum distance we should expect an O type star in intergalactic space is 24.000 ly from the galactic plane (inside the Milky Way). The same calculation can be made for B type stars; considering they should not live more than 90 million years, we shouldn't find any of those more than 360.000 ly from the galactic plane. So there is a gradient in the stellar type for intergalactic stars related to the distance to the closest galaxy that has to be taken into account for the sake of realism.
This is avoinding the idea of stellar formation in intergalactic space, that maybe could show up once in a while. I don't know the probability but it would be awesome to search for blue stars in the middle of giant intergalactic voids, finding one would be awesome, it would mean that a giant gas cloud in the middle of nowhere collapsed because of the existence of an unknown perturbation. But the probability of finding one in the game should be tiny, really tiny.
For M type stars and stars with lifespans of 100 billion years there is not such a big void as to be perfectly clean of runaway M-stars from neighbouring galaxies, so all the intergalactic space should have some M stars from time to time. The only void that could maybe have a central zone depleted from any stars could be the Canes Venatici Supervoid.
For M stars to be absent you have to go 400.000.000 ly away from the galaxy, and this void is 1.300.000.000 of ly across, so maybe at the center you could have distances grater than 400.000.000 ly from the closest galaxy. But it would be a very strange ocurrence in all the SE universe.