According to the Vymannika Shastra, "There are seven sources of power of the vimaana: fire, earth, air, sun, moon, water and sky. The seven kinds of powers are named udgamaa, panjaraa, solar heat absorber, alien force absorber, solar electric dozen, kuntinee, and primary force." We already know of fire, water (hydro), air, sun (solar) power, but what do you think the earth, moon, and sky power could mean? Could earth mean mechanical, and moon mean magnetic? And what is this primary force it speaks of?