After the "Time" lecture and readings you should be able to answer and discuss the following questions.

Which planets are considered to be terrestrial planets? Why?

Which planets are considered to be gas giants? Why?

What is the physical basis for a year?

How long is a year?

What is the average distance from the Earth to the Sun?

What is the physical basis for a day?

How long is a day?

What is the Earth's current axial tilt?

How is axial tilt measured?

What is the plane of the ecliptic?

What is precession?

How long does it take the Earth's axis to make one complete precession?

How many years does it take the Earth's axis to precess one degree?

What are seasons?

What are the two factors which control the change of seasons?

What is an Equinox?

What is the subsolar point?

During an Equinox, where is the subsolar point and the circle of illumination?

What are the dates of the Vernal and Autumnal Equinox?

What is a Solstice?

During a Solstice, where is the subsolar point and the circle of illumination?

What are the dates of the Winter and Summer Solstice?

What are the Tropics of Cancer and Capricorn?

What is the latitude of the Tropics of Cancer and Capricorn?

What are the Arctic and Antarctic Circles?

What is the latitude of the Arctic and Antarctic Circles?

How do the Tropics of Cancer and Capricorn and the Arctic and Antarctic Circles all relate to the Plane of the Ecliptic?

What is time?

Why is this a difficult concept?

What are the basic units of time keeping from smallest to largest?

What are the origins or basis of the week and the month?

What is Solar Time?

What is an Apparent Solar Day?

How does an Apparent Solar Day differ from a Mean Solar Day?

Of these two, which is more commonly used?

What is Lunar Time?

Compare and contrast a Sidereal Month and a Synodic Month.

How many standard time zones are there?

What is Geologic Time?

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