Introduction, Scientific Method and Observation
What is Astronomy ?
a science - includes physics, chemistry, geology, biology .
a human experience - beauty, inspirer of poetry and song
The study of the
Observations, Constellations and Coordinate systems
To express numbers over a large range (like those describing distances in
the solar system), we use scientific notation (powers of 10).
1.62 x 105 = 162,000 . 1
Motions: yearly motion
arise from the orbit of Earth around the Sun
causes different stars to be visible at different times of year in our night sky
stars which are behind the sun in space are in the daytime sky and not
Gravity and the Laws of Motion
History: Newton and Gravity
1670 . England
Recognized that motion of a ball thrown on Earth and motion
of planets are governed by SAME laws of physics.
Mass - amount of matter
We often want to know the force of gravity on the surface of a planet or a
Surface gravity is important for
shape of a planet (will be a sphere if gravity is strong enough)
keeping an atmosphere
Light: General Properties, Temperature
Much of the information we get in astronomy is carried by "light"
What information does "light" contain ?
location of light in the sky . gives position of a planet, moon, or star
Light: Spectroscopy and Atoms
Sometimes we are interested in determining the composition of a star or the
atmosphere of a planet. We can do that by studying the spectrum of light
coming to us from these objects.
Earth: Properties, Interior, Surface
We will examine the Earth and Moon first to get some ideas about what
planets and moons should be like. This will allow us to develop some
models for the rest of the solar system.
Earth: Atmosphere, Magnetic Field
From space Earth looks blue:
1. scattered light in atmosphere
2. reflected light from oceans
molecules and dust in atmosphere scatter light
which colors scatter b
The moon is not a planet, but it is another object in the solar system which we
know alot about. We will examine it is some detail. Then we will step back and see
what predictions we can make from studying Earth an
Having examined the two objects which we know the best, we find they are very
different. We have developed several models, however, which seem to apply to
both Earth and Moon. I summarize those models here before
Solar System Overview
Observations -> Model
We developed models based on our observations of Earth and Moon.
Now we will test those models with observations on each planet.
New observations from:
reflected light fr