Chapters 3, 4, & 5 Flashcards
What is the geocentric model of the universe?
Belief that the Earth was the center of the universe.
Who came up with the idea of the geocentric model?
Greeks
What is the ptolemaic model?
The geocentric model of the universe developed by ptolemy in about 150 A.D.
What is prograde?
The usual movement of the planets from West to East.
What is retrograde?
The “drifting backwards” of the planets from East to West and back to East again.
What is an epicycle?
The individual rotation of a planet or body.
What is a deferent?
The larger circle in which a planet orbits around another planet or body.
What is the heliocentric universe?
Theory that the Sun is the center of the universe.
Who is Copernicus?
Scientist who introduced the idea of a heliocentric (sun centered) universe.
Who is Tycho Brahe?
Scientist who supported Copernicus’ theory of a heliocentric universe but thought that the sun revolved around the earth while the other planets revolved around the sun.
Who is Johannes Kepler?
Scientist who worked under Tycho Brahe for some amount of time and eventually abandoned Tycho Brahe’s original idea of the sun going around the earth and the other planets going around the sun and developed the sun-centered elliptical model.
What is an ellipse?
A ovular shape, not a circle.
- Moderately to highly eccentric
- 2 centers and 2 foci
- 2 radii (1 radius=major axis and 1 radius=semi major axis)
What is Kepler’s first law of planetary motion?
With the sun at one foci, planets go around in elliptical orbits.
What is Kepler’s second law of planetary motion?
Planets sweep equal areas in equal intervals of time (planets closer to the Sun move faster).
What is Kepler’s third law of planetary motion?
The period of a planet is related to the distance to the planet by the equation P2=a3 (harmonic law).
What is an aphelion?
The point at which an object orbiting the Sun is farthest from the Sun.
What is perihelion?
The point at which an object orbiting the Sun is closest to the Sun.
Who was Galileo?
Philosopher and The father of Physics; created the first telescope and discovered tht the mooon is barren. Also discovered Jupiter has many moons.
How did Africans use the orientation of the moon to predict rainfall?
They observed and discovered that the orientation of the “horns” of a crescent moon is relative to the horizon and is closely tied to local rainfall patterns.
Describe the importance of the Egyptian obelisk and Stonehenge in England.
The obelisk was used to tell time and the stone henge was used to make the seasons.
Who suggested the geocentric model of the universe?
Greeks
What is Copernicus’ theory?
- That the sun was the center of the universe.
- The distance between earth and the other planets and the speed of Earths rotation makes other planets appear to go “backwards” in an infinity shape.
What is the harmonic law of planetary motion and how is it used today in interplanetary travel?
The harmonic law states that a period of a planet is relative to the distance to the planet by the equation P2=a3. Scientist use this law to determine how long it will take to travel to a given planet at a given time.