the.com/planet motion
heavy things falling forever and calling it an orbit.
means the movement of planets around the sun, governed by gravity and momentum locked in an endless tug-of-war.
from kepler cracked the code in the early 1600s, ditching perfect circles for ellipses after tycho brahe's decades of stubborn stargazing data; newton later explained why the orbits behaved that way at all.
kepler's second lawplanets speed up when closer to the sun
orbitsellipses, not circles, everyone assumed wrong
mercury's orbitactually shifts slightly, proving einstein right
no engine neededfalling and missing, forever, is the whole trick