Extragalactic rhymes with:
galactic, galactic, galactic, lactic, prophylactic, anticlimactic, chiropractic, climactic, didactic, galactic, lactic, prophylactic, tactic
galactic, galactic, galactic, lactic, prophylactic, anticlimactic, chiropractic, climactic, didactic, galactic, lactic, prophylactic, tactic