I've noticed that sometimes some particles that should be the nearest are under other particles of other objects:
For example, open the milky way - andromeda collision: when you whatch the milky way and behind it there is andromeda, the milky way looks like it is "hidden" by the particle of the other galaxy when it is nearer to you.
o ===> O ===> O
You Milky Andromeda
Way
Andromeda is better visible.
I've noticed this both on this and the old pc