PES 105 General Astronomy I - Exam 2 Study Guide
The Earth
What are the causes of the Earth’s spherical shape, equatorial bulge, and high core pressure?
Why do we think the Earth’s core is iron? How do we deduce details about the interior of the Earth?
What is the most abundant gas in Earth’s atmosphere? What breaks up methane, ammonia, carbon dioxide and
oxygen molecules to change the atmosphere?
What are the greenhouse gases? What is the greenhouse effect?
Where does the Earth’s internal heat come from?
What are tectonic plates? What causes them to move? How is the interior of the Earth structured?
Know the source and effects of the Earth’s magnetic field.
Radioactive decay can be used to estimate the age of the Earth. What is the estimated age?
Precession (top-like rotation of Earth’s axis over 26000 years) is caused by the Sun and Moon acting on the
equatorial bulge.
What weather-related effects does the Coriolis Force cause?
If craters are so prevalent in the Solar System, what happened to the ones on Earth?
The Moon
What is the source of lunar regolith, and the rays around some craters on the moon?
What are lunar rilles and how are they formed? How are craters formed?
Why does the Moon lack an atmosphere and significant internal heat?
What are the long-term effects of tidal braking? At what rate is the Earth slowing down?
How were the lunar maria formed? Why are maria believed to be younger than the lunar highlands?
What effects are observed due to the Moon’s day being equal to its orbit (month)? What does “tidally locked” mean?
What is the prevailing theory about the origin of the Moon?
There is little or no evidence of volcanic activity on the moon, though the inside of the Moon is believed to have
been molten at one time.
Does the Moon currently have a magnetic field? Why or why not?
What are the phases of the moon during Neap and Spring tides, and during eclipses?
What are the types of eclipses? What time of year do eclipses occur?
Which side of the Moon is thicker? What visual clues support this theory?
How much weaker is the Moon’s gravity than Earth’s? How much smaller is the Moon’s mass? Its radius?
Timekeeping
How long is a solar day, a mean solar day, and a sidereal day? How are they defined?
Know the definitions of the International Date Line and the Prime Meridian, and their longitudes.
Know the characteristics and distinctions between the Roman (Julian) Calendar, the Gregorian Calendar, the Julian
Date System, and religious and cultural calendars.
Why are leap days added to calendars? How many days are in a Julian and a Gregorian year?
Which culture is the source of our 24 hour day? Which culture originated division of times into 60 parts?
To which city in England are astronomical times referred?
R. Gist