Early Astronomy
What is a period?
The orbit time of a planet
Kepler's 1st Law has the formula e=c/a. What is the distance from perihelion to aphelion called (a)?
The major axis.
This law explains that planets move faster when closer to the sun and slower when farther from the sun.
What is Kepler's 2nd law?
Creating the Geocentric model
Galileo was the first to observe that Venus orbits the sun.
True or false?
True!
The larger a planet's mass and the shorter the distance between two objects increases it's gravitational force. What law is this?
Bonus 300 Points: Write the formula!
The universal law of gravitation.
F= G((m1*m2)/d2)
The higher an eccentricity number is, what does it tell us about the shape of its orbit?
It is more elliptical (oval shaped)
Kepler's 3rd law would tell us that if Earth's distance from the sun was doubled, it's orbit time would be how long?
a) Less than twice as long
b) Twice as long
c) More than twice as long
c) More than twice as long.
What is Newton's 3rd Law?
For every action, there is an equal an opposite reaction.
This position in a planet's orbit is when it moves faster.
Perihelion
In order to explain retrograde motion, what did Ptolemy propose about planetary orbits.
They moved within their larger orbit in smaller orbits called epicycles.
Kepler's 2nd law states that planets move faster at perihelion. If it took 30 days to move through that area, how long would it take a planet to move through the area of aphelion?
a) Less time
b) the same time
c) More time
b) the same time
Write the formula for Kepler's 3rd law
T2=r3
or
P2=a3
Explain why planets such as Mars, Jupiter, and Saturn appear to move backwards and then forwards in the sky (retrograde motion).
Earth is moving faster than the other planet, approaches the planet, then passes it, looking like the motion in the sky is changing