Earth Science Chapter 21 Quiz

________ accurately recorded the position of the planet Mars.

Brahe

Why did Galileo's observation that Venus showed phases like the Moon indicate that the geocentric theory of the solar system was not possible?

It demonstrated that Venus could not be in orbit around Earth between Earth and the Sun because it shows "full" and "new" phases that would never occur with geocentric geometry.

Which of these men formulated the Law of Universal Gravitation?

Sir Isaac Newton

Why do the planets "drift" east relative to the stars and then move west for periods of time?

They are moving in the same rotation sense as the earth around the Sun, but as the earth moves faster (or slower, depending on the planet) the motion appears to be backwards.

How did Eratosthenes estimate the size of Earth?

They measured the angle of the Sun above the horizon at midday in two places with different latitude and used the angle to estimate the circumference of Earth.

When Earth is the farthest from the Sun, it is said to be in the ________ position.

aphelion

The earliest astronomical records appear to have been made by the ancient Chinese, Egyptians, and Babylonians in order to ________.

determine when to plant crops or hunt animals based on seasonal changes

Solar eclipses are ________ lunar eclipses.

less common than

The ________ day is the time it takes for Earth to make one complete rotation with respect to a star other than our Sun.

sidereal

If you determine the number of days in a year with solar time and sidereal time how would they vary?

A year measured in sidereal time would be about one day longer than a year based on solar time.

In the Ptolemaic (Greek) model of the universe, ________.

Earth was the center of the universe

The first scientist to use a telescope for astronomical purposes was ________.

Galileo

Tyco Brahe set out to disprove Copernicus, so why is he famous for developing modern astronomical theory?

He made very precise measurements that were key data used by Kepler.

Galileo believed in a ________ view of the universe.

Heliocentric

The true shape of the planetary orbits was discovered by ________.

Johannes Kepler

Three laws of planetary motion were discovered by ________.

Johannes Kepler

The first modern astronomer to propose a Sun-centered universe was ________.

Nicolaus Copernicus

Axial precession is sometimes called the precession of equinoxes because it results in a gradual shift, relative to the celestial background, of the position where the Sun crosses the celestial equator at the equinox. Astrology is a mythology based on things like your "sign" which refers to the position of the Sun in the celestial zodiac (the 12 constellations along the ecliptic) on your birthday. This system was established almost two thousand years ago. If this mythology were true (and you believe your horoscope) can you use the dates for your "sign" based on this 2000 year old system?

No, because 2000 years is almost 1/12, or one full sign shift, in the zodiac, so the 2000 year old signs are off by almost one full sign.

Where will the North Star be, relative to the celestial coordinates, 12,000 years from now?

Several degrees from the North Pole position, and Vega will be the North Star instead of Polaris.

This scientist determined the nature of the forces that kept the planets in their orbits.

Sir Isaac Newton

The 5000 year old Stonehenge stone circle of Salisbury Plains, England, allows light shafts to come straight between two rocks on ________ in the Northern hemisphere.

Summer Solstice

Earth hits its perihelion position in January. Solar radiation is proportional to the distance squared between the Sun and the earth, so why isn't it hot in "winter" at perihelion?

The ellipticity of the orbit is small, so the affect is small; seasons are caused by tilt of Earth's orbit.

A statement you will sometimes hear people say is that a day is not 24 hours but is really 23 hr. 56 min. and 4 sec. What does this refer to?

This is sidereal time, not solar time; a solar day is 24 hours.

A very slow motion of Earth's axis that requires 26,000 years to complete is called ________.

axial precession

When the Moon appears as a thin crescent in the evening sky, just after Sunset, the lunar phase is ________.

between new Moon and first quarter

In the Ptolemaic (Greek) model of the universe, the stars are attached to the ________.

celestial sphere

According to the Ptolemaic (Greek) system, the planets have ________ orbits.

circular

Planets appear to move ________ each night, but occasionally they appear to stop and reverse direction.

eastward

The apparent path of the Sun upon the celestial sphere is called the ________.

ecliptic

One of the discoveries which led to the modern view of the solar system was that the orbits of the planets are ________.

ellipses

The proposal that contends that Earth is in the center of the universe is called the ________ view.

geocentric

Lunar eclipses last ________ than solar eclipses.

longer

Using the telescope, Galileo discovered that the planet ________ had polar ice caps not unlike those on Earth.

mars

The cycle of phases of the Moon is the basis for our ________.

month

A total eclipse of the Sun is only possible at ________.

new Moon

The Big Dipper is near the ________ celestial pole.

north

Any variance in the orbit of a planet from its predicted path is referred to as ________.

perturbation

Kepler said that the ________ go(es) around the ________ on ________ orbits.

planets; Sun; elliptical

The apparent westward "drift" of the planets compared to the background stars is called ________.

retrograde motion

What is the modern explanation for "guest stars" that appear in the night sky and then disappear?

stars that go nova or supernova and appear as bright objects during the event and then go away

Galileo discovered that the Sun has "blemishes," which we call ________.

sunspots

The period of time required for the Moon to complete a cycle of phases is called the ________ month.

synodic

The concept that Earth was a sphere was established around the time of ________.

the ancient Greeks

Why were planets called "wanderers" by early astronomers?

they move relative to the starts

Galileo observed several features using the telescope. Which one of the following did he not discover?

two moons of mars

The length of daylight on the Moon is about ________.

two weeks

Relative to the celestial background, the Moon moves ________.

west to east