◎◎◎ perigee ⪢⪢
Now about half a month later, the moon has
orbited halfway around its path and it gets to its closest point to the earth. We refer to this as perigee.
￫ apogee, perihelion
http://qindex.info/i.php?x=9985
○○○ synchronous ⪢⪢
Because the moon's period of rotation is equal to its period of revolution, that is to say, because the moon takes the same amount of time to spin as it does to
orbit the earth, we from the earth only ever see one face of the moon.
http://qindex.info/i.php?x=14015
○○○ heliocentric ⪢⪢
In a heliocentric model the Sun, not the Earth, is in the center and all other objects including the Earth
orbit the Sun. In this model the Earth is moving in two ways. It revolves arround the Sun and it also rotates on an axis.
￫ spin
http://qindex.info/i.php?x=14014
○○○ spin ⪢⪢
Once swallowed, the smaller star continued to
orbit within the larger one which eventually led to the larger star rotating so fast that its mass was spun outwards creating the nebula.
http://qindex.info/i.php?x=19932
○○○ module ⪢⪢
◌◌◌ Moon
