Apparent Motions Part 1
What is the Geocentric Universe?
The idea that Earth was at the centr\er of the universe. All the planets, sun, and moon rotate and revolve aroung Earth
What is Revolution and Period of Revolution?
Revolution: the motion of one body around another in orbit.
Period of Revolution: the amount of time required to orbit the Sun.
What are Ellipses?
the oval shape of a planet's orbit
What is the Moon?
a body that orbits a Planet or Asteroid as they orbit the Sun.
What is a Lunar Eclipse?
The moon is blocked from the Sun by the Earth.
What is the Heliocentric Model?
Current model of the solar system where the Sun is at the center and all the planets revolve around the Sun.
What are Star Trails?
long exposure photos as they move across the sky.
What is Eccentricity?
the degree of flatness or "ovalness" of an ellipse
Eccentricity of a perfect circle is 0, Less Eccentric: more "circular" closer to 0
Eccentricity of a flat line is 1, More Eccentric: more "squashed" closer to 1
How did Earths Moon form?
After an impact with a large asteroid a portion of Earth created the moon.
What are Tides?
cyclic rise and fall of Earth's ocean waters due to gravitational attraction between Earth, Moon, and Sun.
Problems with Geocentric Model?
-Location of the planets could not accurately be predicted.
-Changes in the apparent diameter of the Moon and Sun could not be explained.
What are Circumpolar Stars?
starts that move around a polar star
Part of an Ellipse
Foci
Major Axis
Minor Axis
Hwo long does it take the moon to Rotate and Revolve
It takes the moon 27.3 days for the moon to rotate and revolve.
What are the different Tides?
High Tide: strong gravitational pull
Low Tide: low gravitational pull
What is Rotation and what is Period of Rotation?
Rotation: the movement of an object in a circular motion around around the line of axis.
Period of Rotation: the amount of time to make a complete rotation.
star directly above the North and South Pole.
What is the Foci, Major Axis, and Minor Axis
Foci: two fixed center points of an ellipse.
Major Axis: longest straight lined distance across an ellipse.
Minor Axis: shortest straight lined distance across an ellipse.
How long does it take the moon to complete one moon phase cycle?
It takes 29.5 days for it to complete one complete moon phase cycle.
What is a Spring Tide?
1. A tide with a large range that occurs two times a month. (new moon and full moon)
2. Sun, Earth, and Moon are in a straight line position called sysygy.
Evidence of Rotation
A. Foucault Pendulum: large pendulum when allowed to swing freely changes its path due to Earths rotation.
B. Coriolis Effect: the tendency of all particles on Earth's surface to be deflected from a straight line.
What is Polaris?
The North Star
Eccentricity Formula
Eccentricity= Distance between foci/Length of major axis
What is a Solar Eclipse?
The moon blocks the Earth from the Sun.
What is a Neap Tide?
1. A tide of maximum ranges that occurs during the first and third quarters of the moon.
2. The Sun, Earth, and Moon form a 90 degree angle.