Planet's rhymes with:
planets, planets, gannett's, janet's, planets, baronets, benet's, bennett's, bluebonnets, cabinet's, cabinets, chestnuts, coordinates, electromagnets, gannett's, hornet's, hornets, ignatz, janet's, laminates, magnet's, magnets, minute's, minutes, minutes', peanuts, planets, tenets, unfortunates, units
Planet's sounds like:
palmitic, planets, plant's, plants, plants', plantz, playmates, plummets, plymouth's, poland's, pollinates