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

Day and night

• The earth rotates about its axis once each day, creating day and night.
• Which way does it rotate?
• A traveler flies from Tokyo to San Francisco, leaving Tokyo at 9 pm Sunday evening, just two hours after sunset. While he sleeps, the sun rises. He arrives in San Francisco. The clock at U.S. Customs says 1 pm. What day is it?

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

Seasons

Structure of the reasoning so far:

• Earth rotates counterclockwise as seen from the north.
• Earth revolves around the sun counterclockwise as seen from the north.
• Earth's axis is tilted.

• Day and night.
• Height of the sun above the horizon at noon.
• Seasons.

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