Tarot and the Planets
When Arthur Waite and Pamela Coleman-Smith designed the Rider-Waite-Smith (RWS) deck, between them they managed to include symbology from pretty much every esoteric system available. Therefore it should come as no surprise that astrology and the planets play a large part in the design of the RWS deck.
If you’ve been reading the other posts on this page, you should know by now that the minor arcana cards represent the astrological elements of air (Swords), Earth (Pentacles), fire (Wands) and water (Cups). The major arcana also has specific cards for each astrological sign and therefore, that signs ruling planet as well.