Henrik Isaksson Garnell - Apsis (2011)
"An apsis, plural apsides, is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the centre of attraction, which is usually the centre of mass of the system. Historically, in geocentric systems, apsides were measured from the centre of Earth.
The bedrock basic stratum of reality is irreality; the universe is irrational because it is built not on mere shifting sand — but on that which is not.”