500 billions yes, how many are gas giants, how many are within the habitable zone? And what is the statistical likely hood of life existing in the first place? My point was these are unknowns, the original claim was a guaruntee that life exists on andromeda, a guaruntee is 100% chance. I'm merely stating that it isn't an absolute guaruntee.

To reiterate my point, if a galaxy the size of andromeda absolutely has life then among the billions of galaxies we observe - a type 1 civilisation must exist somewhere using the same logic yet we have yet to observe or find a signal of these possible civilisations.

The Fermi paradox and the Great filter are commonplace thoughts in regards to alien life for a reason.