question

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

answer

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

question

What contribution to astronomy did Eratosthenes make?

answer

He determined the circumference of the Earth.

question

What is meant by the phrase 'angular size'?

answer

how big an object looks, expressed as an angle

question

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

answer

it reduces to one third of what it was

question

The Sun and the Moon have an angular size of approximately ___

answer

0.5 degrees

question

The similarity of the Sun's and the Moon's angular sizes allow ___ to occur.

answer

eclipses

question

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

answer

angular size

question

The Sun and the Moon have the same angular size. If the Sun is 400 times farther away than the Moon, the Sun must be ___ times the size of the Moon.

answer

400

question

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.

answer

one half

question

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

answer

This is an optical illusion.

question

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

answer

the lack of parallax in the stars

question

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

answer

Eratosthenes

question

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

answer

parallax

question

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

answer

greater than

question

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

answer

23 degrees

question

One of the methods used to date supernova remnants (the remains of exploded stars) today is by using

answer

the records of ancient Chinese, Japanese, and Korean astronomers.

question

The ___________ , _____________, _________ and __________ pass through the zodiac.

answer

Earth, Moon, Sun, Planets

question

What is retrograde motion?

answer

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

question

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

answer

east;west

question

Retrograde motion is discernible by watching a planet over the course of

answer

many nights.

question

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

answer

east to west.

question

Imagine the much more massive Jupiter were to switch places with the less massive Mercury. What would accurately describe the outcome?

answer

Jupiter would orbit the Sun in less time than it did before.

question

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

answer

at the time of the Greeks

question

The paths of the planets' orbits lie in ________ in the sky.

answer

a plane

question

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

answer

parallax

question

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

answer

False

question

During retrograde motion, the planet Mars rises in the ___ and sets in the ____.

answer

east; west

question

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

answer

parallax

question

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

answer

geocentric

question

In the _______ 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.

answer

heliocentric

question

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

answer

in the zodiac (near the ecliptic)

question

If you see a bright "star" in the sky, how could you tell whether it is a star or a planet?

answer

Look at it several days later—if it's a planet, it will move across the background stars.

question

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

answer

west to east

question

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

answer

about 70 meters

question

Of the earliest known planets, which exhibits retrograde motion?

answer

Mercury, Venus, & Mars

question

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

answer

retrograde motion

question

Where will a planet in retrograde motion rise?

answer

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

question

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

answer

Mercury, Venus, Mars, Jupiter, and Saturn

question

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

answer

ecliptic

question

The path of the planets through the sky is tipped 23.5 degrees from the ________.

answer

celestial equator

question

The geocentric model was based on the observation that ________.

answer

everything moves around the Earth from east to west

question

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

answer

retrograde motion

question

An epicycle was used in geocentric models to explain ________.

answer

retrograde motion

question

Islamic scholars ________.

answer

studied and expanded upon older texts in astronomy

question

The angular size of an object _____ as the distance to the observer increases.

answer

increases

question

Asian astronomers ________.

answer

recorded the existence of sunspots, kept detailed records of unusual celestial events, and devised ways to predict eclipses

question

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

answer

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

question

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

answer

circular

question

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

answer

a supernova (exploding star); much farther away than the planets and the Sun; the center of the solar system

question

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

answer

it was more aesthetically pleasing than the complicated Ptolemaic model.

question

In ________ models, the Sun is assumed as the center of the solar system.

answer

heliocentric

question

Galileo was the first to observe the phases of ________.

answer

Venus

question

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

answer

Sun; circular

question

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

answer

Tycho Brahe's

question

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

answer

Kepler; Tycho; elliptical

question

The angular size of the Sun as observed from Earth is about ___degree.

answer

0.5

question

Kepler's ________ law states that the orbits of planets are elliptical, with the Sun at one focus.

answer

First

question

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

answer

2nd

question

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

answer

3rd

question

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?

answer

3rd

question

The time between the vernal equinox and the autumnal equinox is somewhat greater than the time between the autumnal equinox and the vernal equinox. This is a result of Kepler's ________ law.

answer

2nd

question

T/F. Copernicus' model was significantly better at predicting future positions of planets than Ptolemy's.

answer

false

question

_____ deduced many empirical laws of motion before Newton was even born.

answer

Galileo

question

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

answer

January

question

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

answer

solar system

question

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

answer

focus

question

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

answer

Moon

question

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

answer

Kepler's

question

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

answer

Copernicus

question

What did Kepler contribute to astronomy

answer

His three laws of planetary motion

question

What did Galileo contribute to astronomy

answer

He discovered four moons of Jupiter

question

Galileo's observation of sunspots showed that ________.

answer

the Sun was not a flawless sphere

question

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

answer

there were objects that did not orbit the Earth

question

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

answer

false

question

Observations supporting the idea of a spherical Earth is that ________.

answer

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, and the shape of the Earth's shadow on the Moon during an eclipse is circular

question

The curved shape of the Earth's shadow during an eclipse was evidence for ________.

answer

a spherical Earth

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