What you see and what is there may not be the same.

Day and night

Daily path of the stars, sun, etc. on the sky


Structure of the reasoning so far:

We have made a model (or a theory).
We deduce consequences that can be tested by observation.

The moon's orbit

The earth's orbit

Motions on the celestial sphere

Motion of the moon

Motion of Venus

Motion of Mars

Motion of Jupiter

ASTR 121 Home
Davison E. Soper, Institute of Theoretical Science, University of Oregon, Eugene OR 97403 USA soper@bovine.uoregon.edu