Along with orbiting around the sun at 66,600 mph, the Earth is also rotating at its axis at about 1,070 miles per hour. So you are simultaneously hurtling around the sun at 66,600 mph while sitting on a rock that is spinning at 1,070 mph. On top of that, our whole solar system is rocketing through space around the center of the Milky Way at around 559,234 mph. On top of that, our galaxy is hurtling through space at around 671,080 mph, with respect to our local group of galaxies. On top of that, for all we know, our entire Universe is careening through some unknown medium at some other ridiculous speed.