science
Heliocentric
based on the belief that the sun is in the center of the universe.
Ellipse
Oval shape the planets take around the sun
nebular hypothesis
The theory that a solar system evolves from a hot gaseous nebula
retrograde
moving backwards
barycenter
The point between two objects where they balance each other
Geocentric
Based on the beleif that the earth is the center of the universe
nutation
wobbling of the earths axis
precession
Change in the orientation of the rotational axis of earth
rotation
spinning of earth on its axis(24 hrs = 1 day)
Revolution
Movement of earth around sun (365 1/4 days = 1 year)
Waxing
Pertaining to the period during which the visible surface of the moon increases
waning
Pertaining to the period during which the visible surface of the moon decreases