Timeline of Astronomy Flashcards
What evidence supported Aristotle’s idea of the geocentric model
The fixed positions of stars in the night sky and the day/night cycle, as well as the orbit of the planets.
What did Ptolemy notice about the motion of planets that led him to introduce the idea of epicycles?
Ptolemy noticed that planets, while orbiting the Earth, occasionally go through retrograde motion.
How did Ptolemy attempt to explain the complex retrograde motions of planets in his model?
Ptolemy introduced the idea of epicycles, which are subcycles within the orbit of planets. However, this solution led to increasingly complex models as more epicycles were added to account for observed motions.
How did Copernicus explain the apparent constancy of stars in their positions?
Copernicus hypothesized that stars remained constant in their positions due to their immense distance, causing negligible parallax.
What technological advancement helped validate Copernicus’s heliocentric model?
The telescope helped validate Copernicus’s heliocentric model by providing observational evidence supporting the motion of planets around the sun.
What key concept did Copernicus introduce in his heliocentric model to explain the retrograde motion of planets?
Copernicus proposed that planets orbit the sun, introducing the heliocentric model.
How did Kepler build on the heliocentric model, and what did he demonstrate about the planets’ orbits?
Kepler demonstrated that planets move in ellipses around the sun, building on the heliocentric model.
What is Kepler’s First Law of Planetary Motion?
The planets orbit in ellipses with the sun at one focus of the ellipse.
Describe Kepler’s Second Law of Planetary Motion.
Planets sweep out equal areas in equal periods of time, regardless of where they are in their orbit.
State Kepler’s Third Law of Planetary Motion.
The square of the period of a planet’s orbit is proportional to the cube of the semi-major axis of its elliptical orbit.
What is the modern explanation for the cause of seasons on Earth?
The seasons are caused by the Earth’s tilted axis about its orbit around the sun.
In astronomy, what is the celestial equivalent of latitude, and how is it measured?
Declination is the celestial equivalent of latitude, with +90 at celestial north and -90 at celestial south.
What is the celestial equivalent of longitude in astronomy, and how is it measured?
Right Ascension is the celestial equivalent of longitude, often measured in hours from 0 to 24 at the celestial equator.
