posted January, 2005, jeb
Course Outline
Exam Schedule
Grading
Mid-term exams (two best of three, each count 30% of grade)
(you only have to take two of three)
Course Project (10%)
Final Exam (counts 30% of grade)
In class unannounced quizzes ()
Quizzes can increase your grade by about two percent
Course Project
Select a project based on your interests and imagination.
Examples:
- written report on a topic of interest
- report of an observational exercise
- poster on a topic
- the design of an astronomical instrument
Typewritten report of 4-6 pages, unless other content (such as a poster) are submitted. In any case, the report should be no less than two pages long.
Projects are due, without exception, no later than March 8th.
Suggested projects will be listed on the web page during the second week of the term.
Successful completion of the final exam and the course project are required to pass the course.
Class attendance is mandatory as the exams will contain material from the lectures as well as the textbook.
Exam, Quiz and Project scores will be posted on the web page
with the last five digits of your student number.
If you wish to
have a different number used, email Professor Brau with the number.
Professor
Inclement Weather
The university is very unlikely to cancel classes due to
inclement
weather.
Although highly unlikely, extremely dangerous weather conditions could
force the university to close.
If this class is cancelled, a notice will be posted on the top of the
class web page.
Astronomy 121, The Solar System, is the first course in a three course sequence:
Astronomy 121, The Solar System
Astronomy 122, Birth and Death of Stars
Astronomy 123, Galaxies and the Expanding Universe
The Sky
The full night sky reveals a concentration of stars (the "Milky Way")
Early astronomers had very practical reasons for studying the sky.
Some constellations served as navigational guides.
For example,
the star Polaris,
part of the Little Dipper, indicates north, and the near-constancy of its location in the sky,
from hour to hour and night to night, has aided travelers for centuries.
Study of the bright points of light in the sky revealed that some of these
objects were
"wanderers".
These "wanderers" did not following the
consistent pattern
of motion of the
rest of the stars in the sky.
Eventually these were identified as the planets, which circle the Sun.
The Planets
Asteroids, Comets and Meteroids
In addition to the planets and their moons,
the Solar System contains many bits of interplanetary debris, including:
Throughout history,
collisions of these objects with Earth has disrupted life.
- The orbital paths of the planets are
elliptical (not circular) with
the sun at
one focus
- An imaginary line connecting the Sun to any planet sweeps out
equal areas
of the ellipse in equal intervals of time
- The square of the planet's orbital period is proportional to the cube
of its semi-major axis
(see table)
Newton's first law of motion:
Newton's second law of motion:
the acceleration of an object is directly proportional to the applied force
.......and inversely proportional to its mass
in other words, the greater the force acting on the
object,
.......or the smaller the mass of the object,
.......the greater its acceleration
Kepler's Laws follow from
Newton
's Law of Universal Gravitation:
The same force (gravity) that determines the motion of celestial
objects (planets, stars, etc.)
....determines the
motion on the Earth
The equation describing the force is:
or Force is proportional to the product of the masses of
the objects
.... divided by the square of the distance between them
This is an
inverse square law
Planetary motion is determined by The Sun's inward pull of gravity
competing with the planet's tendency to continue moving in a straight line.
Escape velocity: Newton's Law of Universal Gravitation explains the
notion of
escape velocity.
Today most people recognize that Astrology is nothing but an amusing diversion
Basics
