ASTRONOMY 101 TEST
1 STUDY GUIDE
Angular distance
The angle that appears to separate two objects in the sky, as viewed form a
location different from either of these objects.
Kepler's First Law of Planetary Motion
The orbit of each planet around the Sun is an ellipse with the Sun at one focus.
Kepler's Second Law of Planetary Motion
As a planet moves around its orbit, it sweeps out equal areas in equal times
Kepler's Third Law of Planetary Motion
The square of the orbital period of a planet is directly proportional to the cube of
the semi-major axis of its orbit (p^2 = a^3). This captures the relationship
between the distance of planets from the Sun, and their orbital periods. More
distant planets orbit sun at slower average speeds.
,Newton's First Law
(Law of Inertia) An object at rest stays at rest and an object in motion stays in
motion with the same speed and in the same direction unless acted upon by an
unbalanced force.
Newton's Second Law
F=ma; Force is equal to the change in momentum (mV) per change in time. For a
constant mass, force equals mass times acceleration.
Newton's Third Law
For every action, there is an equal and opposite re-action.
Kirchhoff's Law of Continuous Spectra
A hot solid, liquid, or gas, under high pressure, gives off a continuous spectrum.
Kirchhoff's Law of Line Spectra
A hot gas under low pressure produces a bright-line or emission line spectrum.
, Kirchhoff's Law of Absorption Line Spectra
A dark line or absorption line spectrum is seen when a source of continuous
spectrum is viewed behind a cool gas under pressure.
The Scientific Method
1. Make observations
2. Ask a question
3. Suggest a hypothesis
4. Make a prediction
5. Perform a test: Experiment or additional observations
If test supports hypothesis, repeat steps 4 and 5 and make additional predictions.
If test does not support hypothesis, revise the hypothesis or start a new one.
Occam's Razor
Of two explanations that account for all the facts, the simpler one is more likely to
be correct.
What makes for a good hypothesis?
That it is an educated, testable prediction.
1 STUDY GUIDE
Angular distance
The angle that appears to separate two objects in the sky, as viewed form a
location different from either of these objects.
Kepler's First Law of Planetary Motion
The orbit of each planet around the Sun is an ellipse with the Sun at one focus.
Kepler's Second Law of Planetary Motion
As a planet moves around its orbit, it sweeps out equal areas in equal times
Kepler's Third Law of Planetary Motion
The square of the orbital period of a planet is directly proportional to the cube of
the semi-major axis of its orbit (p^2 = a^3). This captures the relationship
between the distance of planets from the Sun, and their orbital periods. More
distant planets orbit sun at slower average speeds.
,Newton's First Law
(Law of Inertia) An object at rest stays at rest and an object in motion stays in
motion with the same speed and in the same direction unless acted upon by an
unbalanced force.
Newton's Second Law
F=ma; Force is equal to the change in momentum (mV) per change in time. For a
constant mass, force equals mass times acceleration.
Newton's Third Law
For every action, there is an equal and opposite re-action.
Kirchhoff's Law of Continuous Spectra
A hot solid, liquid, or gas, under high pressure, gives off a continuous spectrum.
Kirchhoff's Law of Line Spectra
A hot gas under low pressure produces a bright-line or emission line spectrum.
, Kirchhoff's Law of Absorption Line Spectra
A dark line or absorption line spectrum is seen when a source of continuous
spectrum is viewed behind a cool gas under pressure.
The Scientific Method
1. Make observations
2. Ask a question
3. Suggest a hypothesis
4. Make a prediction
5. Perform a test: Experiment or additional observations
If test supports hypothesis, repeat steps 4 and 5 and make additional predictions.
If test does not support hypothesis, revise the hypothesis or start a new one.
Occam's Razor
Of two explanations that account for all the facts, the simpler one is more likely to
be correct.
What makes for a good hypothesis?
That it is an educated, testable prediction.
