Vocab
a model of the universe where the sun is at the center
Heliocentric
the castle built on a private island for the purpose of studying the stars
Uraniborg
Describe Copernicus' model
the method of determining the location of an object by measuring the angle from two other objects
triangulation
the task given to Copernicus when he began working for Brahe
plot the orbit of Mars
a model of the universe where the earth is at the center
geocentrism
The reason Tycho decided he needed to get new data on the positions of the heavenly bodies
because he realized the measurements made by the ancient Greeks weren't accurate
4 arguments for Copernicus' theory
1) order & symmetry
2) predicted location of planets as well as Ptolemy's
3) simple
4) beautiful - sun is source of life
the problem Kepler tried to solve using the Platonic solids
what explains the spacing of the orbits
The Law of Elliptical Orbits says:
planets move around an elliptical orbit with the sun at one of the foci
the oval shape of the orbits
ellipse
how did Tycho improve the observations of the heavens?
large, stable instruments
4 arguments against Copernicus' model
1) huge mindset shift - ppl used to Aristotelian philosophy
2) lack of visible parallax
3) earth "heavy & sluggish" - cannot move around sun
4) religious reasons - earth must be center since we're special
the Platonic solids are special because:
equal angles and sides; corners all touch the inside of a sphere around it
the law which states "a line drawn between the sun and a planet sweeps over equal areas in equal time periods"
the Law of Areas
the two points within an ellipse
foci
What did Tycho like about Ptolemy's and Copernicus' model?
simplicity of Cop's model; earth at center of universe (Ptolemy's)
the technical term used to describe the time it takes for a planet to travel once around its orbit
period
the book published by Kepler to explain how he used the Platonic solids to explain the spacing of the orbits
Mysterium Cosmographicum
the law which describes how the planet's average distance from the sun is related to the time it takes that planet to circle the sun
Law of Periods
eccentric
Explain Tycho's model
earth at center, sun around earth, planets around sun
how planets actually move, since they don't have uniform circular motion
they move on an elliptical orbit, moving faster when closer to the sun
the book published by Kepler to explain his first two laws
Astronomia Nova
Kepler's three laws allowed him to do what amazing thing?
determine the position of any planet at any time in the past or future