ASTR test 2

Kepler's third law states that a planet's orbital period, p, is related to its average (semimajor axis) orbital distance, a, according to the mathematical relationship p^2=a^3 . Which of the following statements describe a characteristic of the solar system that is explained by Kepler's third law?

-Inner planets orbit the Sun at higher speed than outer planets. -Venus orbits the Sun faster than Earth orbits the Sun.

Kepler's first law states that the orbit of each planet is an ellipse with the Sun at one focus. Which of the following statements describe a characteristic of the solar system that is explained by Kepler's first law?

-The Sun is located slightly off-center from the middle of each planet's orbit. -Earth is slightly closer to the Sun on one side of its orbit than on the other side.

If an asteroid is in an elliptical orbit about the Sun, with the Sun almost at the center of the ellipse, which of the following would most likely be the eccentricity of the ellipse?

0.018

How many days separate two eclipses that occur within one lunar cycle?

14 days

Each of the following diagrams shows a planet orbiting a star. Each diagram is labeled with the planet's mass (in Earth masses) and its average orbital distance (in AU). Assume that all four stars are identical. Use Kepler's third law to rank the planets from left to right based on their orbital periods, from longest to shortest. If you think that two (or more) of the diagrams should be ranked as equal, drag one on top of the other(s) to show this equality. (Distances are to scale, but planet and star sizes are not.)

2 biggest orbit=same(longest), 2 smaller=same= shortest

Which of the following moon phases corresponds to waning crescent moon?

4

The eccentricity of the Earth's orbit is 0.0167. Which of the following best represents the shape of the Earth's orbit?

A

annular eclipse

A solar eclipse that occurs when the new moon is too far from Earth to completely cover the Sun can be either a partial solar eclipse or a(n)

The diagram below shows the Moon in orbit around the Earth, and indicates the direction from which sunlight emanates. The diagram is not to scale. Which of the moon phases shown at bottom best corresponds to the position of the moon shown in the diagram? (The "white" part of the moon is the illuminated part, the dark part is indeed in darkness e.g. C corresponds to New Moon.)

B

Which of the following pictures indicates an annular solar eclipse as seen by someone on Earth?

B

Two planets are orbiting around stars of the same mass. The orbits of planets are shown below. Both orbits have the same semi-major axis length. Which of the following statements is correct about the orbital periods of the two planets?

Both have the same orbital period.

The planet shown in the drawing below obeys Kepler's Second Law. Each lettered position represents the location for the planet during a particular day. At which lettered position is the planet moving the fastest?

C

Who was the first person to propose the heliocentric model from the list below?

Copernicus

Kepler's second law

Describes how the line that joins a planet and the Sun sweeps out areas as the planet orbits the Sun.

The diagram below shows the Moon in orbit around the Earth, and indicates the direction from which sunlight emanates. Which of the Moon locations in the orbit best corresponds to the phase shown at the left? (The "white" part of the moon is the illuminated part, the dark part is indeed in darkness.)

E

A lunar eclipse occurs when Earth, Moon and Sun are lined up so that

Earth lies between the Moon and Sun

Chapter 3, Question 24, page 78, with one answer choice slightly modified: Earth is closer to the Sun in January than in July. Therefore, in accord with Kepler's second law,

Earth travels faster in its orbit around the Sun in January than in July.

In the drawing below, the motion of a planet traveling around a star is shown. We have shaded in a triangular area that was swept out during the motion of the planet while moving from position A to B. Which two other planet positions (provided below) would sweep out another triangular area for the motion of the planet that would obey Kepler's Second Law?

F to G

Chapter 3, Question 22, page 78: Which of the following was not a major advantage of Copernicus' Sun-centered model over the Ptolemaic model?

It made significantly better predictions of the planetary positions in our sky.

Chapter 3, Question 25, page 78, with one answer choice slightly modified: According to Kepler's third law

Jupiter orbits the Sun at a faster average speed than Saturn.

A solar eclipse occurs when Earth, Sun and Moon are lined up such that

Moon lies between Earth and Sun

The units of force are

Newtons

Kepler's second law states that as a planet orbits the Sun, it sweeps out equal areas in equal times. Which of the following statements describe a characteristic of the solar system that is explained by Kepler's second law?

Pluto moves faster when it is closer to the Sun than when it is farther from the Sun.

Neptune's moon Triton has an orbital radius of 355 kilometers, and it takes around 6 days to travel around Neptune once. Neptune's moon Proteus takes around 27 hours to orbit Neptune once. Therefore:

Proteus has a smaller orbit than Triton

Why do we not see eclipses every new and full moon?

The Earth-Sun-Moon are not always in a straight line at these phases.

The video states that the planetary orbits are shown to scale. Which statement correctly describes the way the planet sizes are shown compared to their orbits?

The planets are all much too large compared to their orbits.

If the Earth's orbit were changed to be a perfect circle, what would happen to our seasons?

We would continue to have seasons like we do at present.

The umbral shadow of an object is

a dark shadow that is smaller than the penumbral shadow.

The Ptolemaic model is

a geocentric (Earth-centered) model

From the Fundamentals of Cosmic Perspective second edition, used with permission: Question: Kepler made a major break from ancient beliefs when he

abandoned circular orbits in favor of elliptical orbits.

Each of the four diagrams below represents the orbit of the same comet, but each one shows the comet passing through a different segment of its orbit around the Sun. During each segment, a line drawn from the Sun to the comet sweeps out a triangular-shaped, shaded area. Assume that all the shaded regions have exactly the same area. Rank the segments of the comet's orbit from left to right based on the length of time it takes the comet to move from Point 1 to Point 2. Rank from longest to shortest. If you think that two (or more) of the diagrams should be ranked as equal, drag one on top of the other(s) to show this equality.

all are equal (middle of longest and shortest, stacked)

Each of the four diagrams below represents the orbit of the same asteroid, but each one shows it in a different position along its orbit of the Sun. Imagine that you observed the asteroid as it traveled for one week, starting from each of the positions shown. Rank the positions based on the area that would be swept out by a line drawn between the Sun and the asteroid during the one-week period. Rank from largest to smallest. If you think that two (or more) of the diagrams should be ranked as equal, drag one on top of the other(s) to show this equality.

all the same

A geocentric model of the universe

any model that place Earth at the center of the universe.

According to Kepler's second law, Jupiter will be traveling most slowly around the Sun when at _______

aphelion

The following diagrams all show the same star, but each shows a different planet orbiting the star. The diagrams are all scaled the same. (For example, you can think of the tick marks along the line that passes through the Sun and connects the nearest and farthest points in the orbit as representing distance in astronomical units (AU).) Rank the planets from left to right based on their average orbital distance from the star, from longest to shortest. (Distances are to scale, but planet and star sizes are not.)

biggest to smallest orbit

Consider again the diagrams from Part A, which are repeated here. Again, assume that all the shaded areas have exactly the same area. This time, rank the segments of the comet's orbit from left to right based on the distance the comet travels when moving from Point 1 to Point 2. Rank from longest to shortest. If you think that two (or more) of the diagrams should be ranked as equal, drag one on top of the other(s) to show this equality.

biggest/widest shaded area to smallest

The figure below shows the orbit of Halley's comet. The orbit has an eccentricity of 0.97. Which of the positions indicated best represents the location of the Sun in this orbit?

c

For a total solar eclipse to occur, the Moon must be in the part of its orbit that puts it

closer to Earth

Consider again the diagrams from Parts D and E, which are repeated here. Again, imagine that you observed the asteroid as it traveled for one week, starting from each of the positions shown. This time, rank the positions (A-D) from left to right based on how fast the asteroid is moving at each position. Rank from fastest to slowest. If you think that two (or more) of the diagrams should be ranked as equal, drag one on top of the other(s) to show this equality.

closest to furthest from sun

Consider again the diagrams from Parts A and B, which are repeated here. Again, assume that all the shaded areas have exactly the same area. This time, rank the segments of the comet's orbit based on the speed with which the comet moves when traveling from Point 1 to Point 2. Rank from fastest to slowest. If you think that two (or more) of the diagrams should be ranked as equal, drag one on top of the other(s) to show this equality.

closest to sun to furthest from sun

Consider again the diagrams from Part D, which are repeated here. Again, imagine that you observed the asteroid as it traveled for one week, starting from each of the positions shown. This time, rank the positions from left to right based on the distance the asteroid will travel during a one-week period when passing through each location. Rank from longest to shortest. If you think that two (or more) of the diagrams should be ranked as equal, drag one on top of the other(s) to show this equality.

closest(longest) to furthest(shortest) from sun

Chapter 3, Question 26, page 78: Tycho Brahe's contribution to astronomy included:

collecting data that enabled Kepler to discover the laws of planetary motion.

A total lunar eclipse occurs when the moon is

completely in the umbral shadow of the Earth

As seen from above, the Moon orbits the Earth

counter-clockwise

Kepler's first law

describes the shape of the orbit of a planet.

The extent to which Mars' orbit differs from a perfect circle is called its _______

eccentricity

Earth orbits in the shape of a/an _________around the Sun.

ellipse

Newton found that orbits can be

ellipses, circles, hyperbolas and parabolas (bound and unbound orbits)

Newton's Law of Gravitation

explains how to determine the strength of the gravitational force between the planet and the Sun.

The following diagrams are the same as those from Parts A and B. This time, rank the planets from left to right based on their average orbital speed, from fastest to slowest. If you think that two (or more) of the diagrams should be ranked as equal, drag one on top of the other(s) to show this equality. (Distances are to scale, but planet and star sizes are not.)

fastest=smallest orbit, slowest= biggest orbit

Earth is located at one _____ of the Moon's orbit

focus

A lunar eclipse occurs at

full moon

Four pairs of objects, A - D, are shown in the figure below. The masses and separations are shown in arbitrary units. Rank the strength of the gravitational force between each pair from greatest to least.

greatest D, C, B, A least

The figure below shows 5 pairs of rocky asteroids with masses (m), expressed in arbitrary units, separated by a distance (d), also expressed in arbitrary units. Rank from greatest to least the strength of the gravitational force exerted on the asteroid located on the right side of each pair

greatest E, B, C, A, D least

The figure below shows 5 pairs of rocky asteroids with masses (m), expressed in arbitrary units, separated by a distance (d), also expressed in arbitrary units. Rank from greatest to least the strength of the gravitational force exerted on the asteroid located on the left side of each pair.

greatest E, B, C, A, D least

In the picture below, a spacecraft is shown traveling to the Moon. Five possible positions (A - E) for this spacecraft are shown. Rank greatest to least the strength of the gravitational force at positions A - E exerted by the Moon on the spacecraft.

greatest E, D, C, B, A least

How much of the Moon's surface is illuminated by the Sun?

half

Suppose you see a crescent Moon; how much of the Moon's entire surface (the full globe of the Moon) is in daylight?

half

Which of the following is not a phase of the Moon?

half moon

The units of mass are

kilograms

The following diagrams are the same as those from Part A. This time, rank the planets from left to right based on the amount of time it takes each to complete one orbit, from longest to shortest. If you think that two (or more) of the diagrams should be ranked as equal, drag one on top of the other(s) to show this equality. (Distances are to scale, but planet and star sizes are not.)

longest= biggest orbit, shortest= smallest orbit

A solar eclipse occurs at

new moon

A point at which the Moon crosses Earth's orbital plane is called a(n) node

node

As seen from the Earth, the moon orbits the Earth in about

one month

Chapter 4, Question 32, page 103 (with one more answer choice): If Earth were twice as far as it actually is from the Sun, the force of gravity attracting Earth to the Sun would be

one-quarter as strong.

During some lunar eclipses, the Moon's appearance changes only slightly, because it passes only through the part of Earth's shadow called the

penumbra

According to Kepler's second law, Pluto will be traveling fastest around the Sun when at __________

perihelion

Chapter 2 Question 34, page 51: The fact that we always see the same face of the Moon tells us that the Moon

rotates with the same period that it orbits Earth..

The mathematical form of Kepler's third law measures the period in years and the ________________ in astronomical units (AU).

semimajor axis

The figure shows a comet's orbit around the Sun. Rank the time the comet takes to travel through the regions shown, going from shortest to longest time as best as you can.

shortest 1, 2=4, 3 longest

The figure below shows four identical stars, and four planets of various masses in circular orbits of various size. In each case the mass of the planet is given in Earth masses and the orbital distance is given in Astronomical Units (AU). Note that the sizes of the stars and the orbital distances have not been drawn to scale. Which of the following is the best possible ranking for the period of the orbit of these planets from shortest to longest?

shortest A = C < B = D longest

When you read the speedometer in your car, this tells you your

speed

Kepler's 3rd law

tells us how the orbital period of a planet changes when the size of the orbit is changed.

The reason we do not have a solar eclipse at every new moon is that

the Moon's orbit is inclined relative to Earth's orbit around the Sun.

Chapter 2 Question 35, page 51: If there is going to be a total lunar eclipse tonight, then you know that

the Moon's phase is full.

Chapter 3, Question 21, page 78: In the Greek geocentric model, the retrograde motion of a planet occurs when

the planet actually goes backward in its orbit around Earth.

We see phases of the moon because

the position of Moon relative to the Sun and the Earth changes over one lunar cycle.

Nodes of the Moon's orbit refer to

the positions where the Moon's orbit intersects the Earth's orbital plane.

The Spitzer Space Telescope is in the same orbit as the Earth, but it orbits some distance behind Earth. Therefore, its orbital period is

the same as Earth's.

Anyone looking from the night side of Earth can, in principle, see a(n)

total lunar eclipse

A _________can occur only when the Moon is new and has an angular size larger than the Sun in the sky.

total solar eclipse

During an annular solar eclipse, you learned that the Moon is farther from the Earth than during a total solar eclipse. This means the Moon's orbit is elliptical. It in fact has an eccentricity of 0.055. Therefore, the Moon is traveling faster during which eclipse?

total solar eclipse, when it is closer to the Earth

A partial lunar eclipse begins when the Moon first touches Earth's

umbra

The following image depicts which Moon phase?

waning gibbous moon

To be able to determine if Mars is undergoing retrograde motion,

we need to observe it for several nights in a row.

Say your friend told you that Saturn is showing retrograde motion. Your friend concludes that Saturn is moving backwards as it travels in the sky. You say that

you disagree, because Saturn is really moving forward in its orbit and Earth is overtaking Saturn, so it appears that Saturn moves backwards (or retrograde).