History of Astronomy Practice Flashcards

Practice flashcards covering the history of astronomy from ancient structures like Stonehenge to the laws of planetary motion by Kepler.

When was Stonehenge constructed and where is it located?

Constructed between $3000 – 1800\text{ B.C.}$ in Great Britain.

What are the primary astronomical alignments found at Stonehenge, and what was its likely function?

Alignments with locations of sunset, sunrise, moonset and moonrise at summer and winter solstices; probably used as a calendar.

Which rising stars are aligned with the Big Horn Medicine Wheel in Wyoming?

Sirius, Rigel, and Aldebaran.

By which culture was the Caracol in Mexico built, and approximately when?

Built by the Maya culture around $\text{A.D. } 1000$.

What celestial events are associated with the Caracol observatory in Mexico?

Venus maximum (Northern and Southern setting), Equinox sunset, and Achernar setting.

What is the Geocentric belief followed by early astronomers?

The belief that Earth was the center of the universe.

What was the 'Pythagorean Paradigm' established in $475\text{ B.C.}$?

A set of rules meaning 'common sense' stating that planets, Sun, Moon, and Stars move in perfectly circular orbits at constant speeds with Earth at the center.

What were Aristotle's ($322\text{ B.C.}$) views on the composition and motion of celestial bodies?

He believed planets, the moon, and the sun were stuck on perfect crystalline spheres and were 'perfect' and unchanging.

How did Aristotle define 'retrograde motion'?

The occurrence where planets seem to move backwards in their movement throughout the year and get brighter as they do so.

How did Ptolemy ($165\text{ A.D.}$) explain retrograde motion in his Geocentric model?

Using epicycles, which are small circles stuck to larger circles called deferents that represent the orbit.

What adjustment did Ptolemy build into his model to explain varied distances of the deferent?

He built in a 'wobble' to explain why the deferent was not always a constant distance away.

What was a major flaw in Ptolemy’s model involving crystalline spheres?

If planets were on crystalline spheres, the epicycle would crash into the sphere.

What scientific shift characterized the work of scientists $1500$ years after Ptolemy?

A shift to the Heliocentric universe where the Sun is the center.

What were the key features of Nicolaus Copernicus' (1543 A.D.) model?

He was the first to create an acceptable model with the sun at the center, placing the planets in the correct order up to Saturn.

What is an ASTRONOMICAL UNIT or AU, as derived from Copernicus' calculations?

A measurement of how many times a planet is farther from the sun as compared to Earth.

According to Copernicus, what is the cause of retrograde motion?

It is an optical illusion caused by the projected position of a planet on the background of stars as earth passes it.

What was Galileo Galilei ($1642\text{ A.D.}$) the first to record doing?

He was the first recorded person to use a telescope to observe the planets, sun, or moon.

What specific evidence did Galileo find to prove planets and celestial bodies were not 'perfect'?

He discovered the moon had huge craters, the sun had spots, and Jupiter had its own moons.

What was Johannes Kepler’s ($1630\text{ A.D.}$) major discovery regarding planetary orbits?

He discovered that planets do not orbit in circles but in ellipses (ovals).