ΔE 26.0, loose: different enough that you should pick on purpose. Pale Blue Dot is noticeably lighter, much more saturated, cooler than Alien Purple.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 26). Pale Blue Dot is noticeably lighter, much more saturated, cooler than Alien Purple.
The same difference applies the other way round: Alien Purple is noticeably darker, much more muted, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Alien Purple on the colour wheel See Pale Blue Dot on the colour wheel
All matches: Alien Purple equivalents · Pale Blue Dot equivalents