it's quite different but there are many concepts that are in both. there are lots of threads on here about the differences but real quick summary i'd say:
-it's more variable game to game as the map can change, the technologies available can change and the positions of those technologies on the replacement cult track can change - as an example imagine if Earth 1 ability - 2 VP per dwelling changed favor tiles game to game.
-the cult track has been replaced with a technology track which has 6 columns instead of 4. those technologies improve your ability to terraform / give you income / give you special abilities / etc.
-if you've played TM before you will pick up the rules quickly and easily. if you haven't the rules / leaning this game will be significantly harder than learning TM