Kwinkqubo yebhokisi yegiya yeplanethi, umthwali weplanethi udlala indima ebalulekileyo kuwo wonke umsebenzi kunye noyilo lwebhokisi yegiya. Ibhokisi yegiya yeplanethi inamacandelo amaninzi, kuquka aizixhobo zelanga,izixhobo zeplanethi,igiya yeringi,kunye nomthwali weplanethi. Nasi isizathu sokuba umthwali weplanethi ubalulekile:

Inkxaso yeeGear zePlanethi:

Umthwali weplanethi usebenza njengesiseko senkxaso yezixhobo zeplanethi. Isijikelezi-langa sigiya umnatha ngazo zombini iigiya zelanga kunye negiya yeringi, kwaye zijikeleza kwigiya yelanga ngelixa zikwajikeleza i-axis esembindini yesithwali seplanethi.

Ukuhanjiswa kweTorque:
Itorque eveliswa ligalelo (eliqhagamshelwe kwigiya yelanga okanye isithwala iplanethi) igqithiselwa kwimveliso ngokusebenzisaizixhobo zeplanethi. Umthwali weplanethi unceda ukusasaza le torque kwiigiya zeplanethi, ezivumela ukuba zijikeleze kwaye zibe negalelo kunciphiso lwegiya ngokubanzi okanye ukonyuka kwesantya.

Ukuhanjiswa komthwalo:

Umthwali weplanethi unceda ukusabalalisa umthwalo phakathi kweizixhobo zeplanethi.Olu nikezelo luqinisekisa ukuba umthwalo kwigiya nganye ulungelelene, ukuthintela ukugcwala kwegiya nganye kunye nokukhuthaza ukuqina nokuthembeka kwebhokisi yegiya.