Astronomy Flashcards

Flashcards covering key concepts from the Astronomy lecture, including ancient roots, Greek science, the Copernican Revolution, and the nature of science.

What is scientific thinking based on?

Everyday ideas of observation and trial-and-error experiments.

What are some systems rooted in ancient astronomy?

Daily timekeeping, tracking the seasons, calendars, monitoring lunar cycles, and predicting eclipses.

Which celestial bodies were the days of the week named after?

The Sun, Moon, and visible planets.

What was the purpose of the Egyptian obelisk?

To tell the time of day using shadows.

What is Stonehenge, and when was it completed?

An ancient monument in England, completed around 1550 B.C.

What could ancient people of central Africa (6500 B.C.) predict from the orientation of the crescent Moon?

Seasons

Why does modern science trace its roots to the Greeks?

The Greeks were the first people known to make models of nature and explain patterns without myth.

When did the Library of Alexandria thrive?

Starting after 300 B.C. for centuries.

What is the Greek geocentric model?

A model with the Earth at the center of the universe and the heavens moving in perfect circles (c. 400 B.C.).

Who was Eratosthenes?

He measured the circumference of the Earth around 240 B.C.

What are the underpinnings of the Greek geocentric model?

Earth at the center and heavens "perfect" with objects moving in perfect spheres or circles.

What is the Ptolemaic model?

The most sophisticated geocentric model, accurate enough to remain in use for 1,500 years.

What did Copernicus propose?

A Sun-centered model of the solar system (published 1543).

What was Tycho Brahe known for?

Compiling the most accurate naked eye measurements of planetary positions.

Who was Johannes Kepler, and what did he discover?

He used Tycho's observations to discover the truth about planetary motion, including elliptical orbits.

What is Kepler's First Law?

The orbit of each planet around the Sun is an ellipse with the Sun at one focus.

What is Kepler's Second Law?

As a planet moves around its orbit, it sweeps out equal areas in equal times.

How do planets move according to Kepler's Second Law?

Planets travel faster when nearer the Sun and slower when farther from the Sun.

What is the major difference between the geocentric and Sun-centered models?

Earth is stationary in the geocentric model but moves around the Sun in the Sun-centered model,

What is Kepler's Third Law?

More distant planets orbit the Sun at slower average speeds, following the relationship p^2 = a^3.

How did Galileo solidify the Copernican Revolution?

He overcame major objections to the Copernican view through experiments and observations.

What did Galileo's experiments show about motion?

Objects in the air would stay with Earth as it moves; objects stay in motion unless a force acts to slow them down.

What observations did Galileo make with his telescope?

Sunspots on the Sun, mountains and valleys on the Moon, and four moons orbiting Jupiter.

What did Galileo's observations of Venus reveal?

Venus orbits the Sun, not Earth.

What are the hallmarks of modern science?

Explanations based solely on natural causes, creation and testing of models, and testable predictions.

What is a scientific theory?

A model that explains a wide variety of observations with few simple principles, supported by evidence, and that has not failed any crucial test.

How does astronomy differ from astrology?

Astronomy is the scientific study of celestial objects, while astrology is a belief in hidden influences on human lives based on celestial positions.

What is science from the Latin scientia?

knowledge

What is an educated guess?

hypothesis