SOLUTIONS to Homework 1.

1. Sketch the phases of Jupiter as seen from (a) Earth, and (b) Saturn.
Show the location of the planets in their orbits,
and the corresponding appearance of Jupiter.

notes & sketch to (a)
notes & sketch to (b)

2. Discuss the common characteristics of the physical sciences.
How are they different from the life sciences?
How does astrology differ?


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Physical Sciences: Predictive theories, Mathmatical foundation,
High precision prediction & measurement are goals and are often achieved.
Much of physics can be derived from a few fundamental concepts.

Life Sciences: Complete complex systems (e.g. DNA, cells) which are
allowed by evolution to become even more complex, in both
an individual and corporate sense.
Parts make little sense without regarding full enviroment.
e.g. a cell is a part of a whole organism.

Astrology: Predictions vague & unreliable. No underlying theory.

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3. Explain the astronomical basis for the following lengths of time:
a. year
*** Earth's revolution around Sun.
b. month
*** Moon's revolution around Earth.
c. day
*** Earth's rotation (spin about polar axis)


4. A planet is said to be at opposition when it is
on the other side of the sky from the sun (opposite the sun).
Why is Mars (or Jupiter, Saturn,) brightest when it is at opposition?
a. When a planet at opposition it is closest to the Earth.
And when an object is nearer, it appears brighter even as it reflects the same amount of light.


b. In this position the planet is in full phase - the full disk is illuminated,
meaning that a maximum amount of light from the illuminated surface reaches us.

c. The geometry of oppostion means the sunlight is more direct.
Sunlight at an angle upon a rocky relief creates shadows,
thereby darkening parts of the surface - an effect which is least at opposition.
This is only for Mars, though. Jovian surfaces are gaseous & smooth.
notes & sketch