Astronomy Ch 2

Asian astronomers _________.

(All of these choices are correct) Kept detailed records of unusual celestial events, Devised ways to predict eclipses, Recorded the existence of sunspots

Islamic scholars _________.

(All of these choices are correct) Studied and expanded upon older texts in astronomy, Made detailed studies of the motions of the planets, Influenced the naming of bright stars, Developed algebra

One of Tycho Brahe's major contributions to astronomy was to prove that _________ was _________.

(Both A and B) a supernova (exploding star); much farther away than the planets & a comet; outside Earth's atmosphere

One observation supporting the idea of a spherical Earth is that _________.

(all of these choices are correct) The shape of Earth's shadow on the Moon during an eclipse is circular; A traveler moving south will see stars they could not previously see; A ship moving away from the observer will move such that the hull is not seen, then the sails

The Sun and the Moon have an angular size of approximately ____.

0.5 degrees

The paths of the planets in the sky are tilted with respect to the celestial equator by about

23 degrees

What is the size of an object located at a distance of 1,000 meters and that has angular size A = 4 degrees?

About 70 meters

Which of the following objects passes through the zodiac?

All of these choices are correct. (Sun, Planets, earth & moon)

The apparent size of an object based on the amount of sky it covers is called its ____.

Angular size

_________ was the first person to measure the circumference of Earth.

Eratosthenes

Copernicus' model was significantly better at predicting future positions of planets than Ptolemy's.

False

During retrograde motion, the planet Mars rises in the west and sets in the east.

False

The Sun is located at the center of Earth's elliptical orbit.

False

The concept of the epicycle was introduced in the heliocentric model to explain the retrograde motion of the planets.

False

The motion of the Sun with respect to the stars is retrograde, i.e., east to west relative to the stars.

False

The paths of the planets' orbits lie in all different directions in the sky.

False

Tycho Brahe relied on the use of telescopes to record his accurate positions for the planets.

False

Which of the following is a contribution that Eratosthenes made to astronomy?

He determined the circumference of earth

Which of the following is a contribution that Galileo made to astronomy?

He discovered four moons (or satellites) of Jupiter.

Which of the following is a contribution that Kepler made to astronomy?

He discovered his Three laws (of Planetary Motion).

Where will a planet in retrograde motion rise?

In the east (just like everything else in the sky).

If you triple your distance from an object, what happens to its angular size?

It reduces to one third of what it was.

_______ used the extensive records of planetary positions measured by ______ to discover that the orbits of the planets are ________.

Kepler; Tycho; elliptical

The planets (other than Earth) known to ancient Western cultures were ____.

Mercury, Venus, Mars, Jupiter, and Saturn

Of the terrestrial planets, or inner planets, which exhibit(s) retrograde motion?

Mercury, Venus, and Mars

One of two identical buildings is nearby, the other is twice as far away as the first. The angular size of the more distant building is ____ the nearby building's angular size.

One half

One phenomenon that the geocentric models struggled to explain was ____.

Retrograde motion

What do we call it when a planet moves backward (east to west) through the stars?

Retrograde motion

From Kepler's ____ law, we conclude that the planets do not move with constant speed.

Second

Kepler's Third, or harmonic, law states that the

Semi-major axis of an orbit cubed equals the period squared.

In Copernicus' model of the solar system, the planets orbited the _____ in ______ orbits.

Sun; circular

Galileo's observation of sunspots showed that _________.

The sun was not a flawless sphere

From Kepler's ____ law, we conclude that Mars completes a full orbit much faster than Pluto.

Third

Observations indicate that it takes Saturn longer than Jupiter to complete one orbit about the Sun. This is in agreement with which of Kepler's laws?

Third

When the Moon is on the horizon, it appears larger than when it is high in the sky. Why?

This is an optical illusion.

According to Kepler's laws the Sun is located at one of the foci of Earth's orbit.

True

Copernicus was able to calculate the distances to the observed planets relative to Earth's distance from the Sun.

True

During the month of January, Earth goes through the point of closest approach to the Sun. Using Kepler's Second law we can conclude that Earth moves faster in January than in July.

True

In the heliocentric model, the retrograde motion of the planets was explained as the consequence of the different orbital speeds of the planets, without the use of epicycles.

True

Parallax is the shift in a star's apparent position due to Earth's motion around the Sun.

True

The angular size of the Moon as observed from Earth is about 0.5 degree.

True

The inability to observe parallax of stars contributed to the ancient Greek astronomers' rejection of the idea that Earth revolves around the Sun.

True

______ major contribution to astronomy is his extensive series of measurements of planetary positions.

Tycho Brahe's

Galileo was the first to observe the phases of _____.

Venus

The planets move ____ through the sky, relative to the background stars.

West to east

When was it first known that Earth was spherical in shape?

at the time of the Greeks

Copernicus' heliocentric model failed to work as well as it might fail to predict the positions of planets because Copernicus insisted the orbits were

circular

During the course of a single night, a planet that is moving in retrograde motion will move

east to west.

During retrograde motion, a planet moves from ______ to ______ relative to the stars.

east; west (moves westward)

As the planets orbit the Sun, they are never far from the ____ on the celestial sphere.

ecliptic

The geocentric model was based on the observation that _________.

everything moves around Earth from east to west

The parallax shift of a nearby star would be ____ that of a more distant star.

greater than

Where on the celestial sphere would you look for the planets?

in the zodiac (near the ecliptic)

The general heliocentric model proposed by Copernicus was appealing, and eventually became preferred, because

it was more aesthetically pleasing than the complicated Ptolemaic model.

The Moon appears larger when it rises than when it is high in the sky because

it's an illusion from comparison to objects on the horizon.

What is retrograde motion?

occasional east to west motion of the planets relative to the stars over many successive nights

The shift of a star's apparent position due to Earth's motion around the Sun is called ____.

parallax

One observation that supported an Earth-centered solar system is _________.

the lack of parallax in the stars

Galileo's observation of the satellites of Jupiter showed that _________.

there were objects that did not orbit Earth

In geocentric theories, Earth is assumed to be the center of the solar system.

true