astronomy hw 2

Which stars we see at night depends onChoose one or more:A.our location on Earth.B.the motion of stars relative to one another over the course of the year.C.the time of the observation.D.Earth's location in its orbit.

:A.our location on Earth.C.the time of the observation.D.Earth's location in its orbit.

We always see the same side of the Moon because Choose one:A. the Moon does not rotate on its axis.B. the Moon rotates once each revolution.C. when the other side of the Moon is facing toward us, it is unlit.D. when the other side of the Moon is facing Earth, it is on the opposite side of Earth.E. None of the answer options are correct.

.B. the Moon rotates once each revolution.

During the day, the Sun is too bright for us to see where it is located with respect to the constellations, but we can use our observations of stars at night to figure this out. Based on the way stars shift position over the course of a year, your knowledge of how the time of day is defined, and the fact that the same constellations are seen at the same place in the sky at the same time of night on a given day of the year, which of the following is most likely correct?Choose one:A. The Sun's apparent location with respect to the constellations is random and cannot be predicted.B. The Sun always appears to be in front of the same constellation.C. The Sun appears to move across the constellations over the course of a 24-hour period, ending where it started with respect to the background stars by the end of that period.D. The Sun appears to move across the constellations over the course of a year, ending where it started with respect to the background stars by the end of that period.

.D. The Sun appears to move across the constellations over the course of a year, ending where it started with respect to the background stars by the end of that period.

Day and night are caused by theChoose one:A. revolution of Earth about the Sun.B. tilt of the Earth on its axis.C. revolution of the Sun about the Earth.D. rotation of the Earth on its axis.

.D. rotation of the Earth on its axis.

Celestial motions over time periods longer than a day are less obvious. Say you went out at exactly the same time each night and looked at the sky, noting the position of a specific set of stars at that time with respect to reference objects on Earth, such as trees and buildings. The following figure shows how the stars would change position. Based on this figure, what is the most correct conclusion?Choose one:A. The stars' positions in our sky do not change from one night to the next.B. The stars appear to move eastward from one night to the next.C. The stars appear to move westward throughout the course of a single night. D. The stars appear to move eastward throughout the course of a single night.E. The stars appear to move westward from one night to the next.

.E. The stars appear to move westward from one night to the nex

. No matter where you are on Earth, stars appear to rotate about a point called thea. zenith.b. celestial pole.c. nadir.d. meridian.e. equinox.

.b. celestial pole

What time of day is it for the person shown on the Earth when you intially open this simulation?Choose one:A. noonB. sunset, about 6:00 P.M.C. sunrise, about 6:00 A.M.D. midnight

A. noon

Label these important reference points. Their location in your sky depends on your location on Earth.

AHorizon BNorth celestial pole CZenith DCelestial equator

The diagram shows the zodiacal constellations viewable from Earth at different seasons. Label the month that the Sun appears in each marked constellation.

April- PiscesOctober - VirgoMarch - AquariusMay - Taurus

If Earth's axis were tilted by 45°, instead of its actual tilt, how would the seasons be different than they are currently?Choose one:A. The seasons would remain the same. B. Winters would be colder.C. Winters would be shorter.D. Summers would be colder.

B. Winters would be colder

Polaris, the North Star, is unique because itChoose one:A. is the brightest star in the night sky.B. is the only star in the sky that doesn't move throughout the night.C. has a longer path above the horizon than any other star.D. is always located at the zenith for any observer.

B. is the only star in the sky that doesn't move throughout the nigh

Rank the phases of the Moon in the order they appear in one lunar cycle as seen from the Northern Hemisphere, starting with a new Moon. You may need to click on the arrow to scroll through the full range of possibilities.

Black-Right little white-Left little black-Full white-half and half

Watch the Astronomy in Action video about seasons, and answer the following question.If you have trouble loading the video or would like to open it in a new tab, please click here.What causes the angle of the Sun to change over the year?

C. Earth's North Pole always points in the same direction in space. Sometimes this is toward the Sun, and sometimes it's away from the Sun.

From our point of view on Earth, it feels as if we are stationary and the celestial sphere and Sun are all rotating around us. In actuality, however, the Earth is moving, rotating on an axis that is tilted with respect to the orbit it takes around the Sun.Open the AstroTour called "The Earth Spins and Revolves." Watch the Introduction, and the first half of the Explanation (up until the interactive part). Then, choose one of the following conclusions that best explains the cause of the shift from day to night.Choose one:A. The shift from day to night is caused by the Sun's orbit around the Earth.B. The shift from day to night is caused by the orbit of the Earth around the Sun.C. The shift from day to night is caused by the rotation of the Earth around its axis.D. The shift from day to night is caused by the tilt of the Earth's rotation axis in relation to its orbit around the Sun.

C. The shift from day to night is caused by the rotation of the Earth around its axis.

Consider all the evidence about variations in the Sun's influence on the Earth throughout the year. Based on this evidence, what causes the seasons?Choose one:A. The tilt of the Earth's rotation axis to its orbit around the Sun causes the hemisphere tilted toward the Sun to be warmer than the opposite hemisphere because it is physically closer to the Sun.B. The elliptical shape of Earth's orbit around the Sun causes the Earth to be closer to the Sun during the summer than the winter.C. The tilt of the Earth's rotation axis to its orbit around the Sun causes parts of the Earth to experience more direct illumination from the Sun and longer days during the summer than the winter. D. The Sun varies in brightness throughout the year due to cyclical changes in the number of sunspots on its surface.

C. The tilt of the Earth's rotation axis to its orbit around the Sun causes parts of the Earth to experience more direct illumination from the Sun and longer days during the summer than the winter

Arrange the observer and the Moon so that the Moon is full and crossing the meridian. What time is it for the observer?Choose one:A. 6:00 A.M.B. 6:00 P.M.C. midnightD. noon

C. midnight

You see the Moon on the meridian at sunrise. The phase of the Moon isChoose one:A. full.B. first quarter.C. third quarter.D. new.E. waxing gibbous.

C. third quarter.

Examine the following figure, which demonstrates star trails that would be visible in a photo centered on the North Star (Polaris) when the camera's shutter is left open to reveal the path the stars are taking as they move during part of one night. Which of the following best describes your observations? Choose one or more:A.All of the stars move from east to west.B.Some stars move in a counterclockwise path around Polaris, while others move in a clockwise path. C.All of the stars move in a counterclockwise path around Polaris. D.The stars closest to Polaris move in smaller circles. E.All of the stars move in a clockwise path around Polaris. F.Each star moves in a circular path of the same radius.

C.All of the stars move in a counterclockwise path around Polaris. D.The stars closest to Polaris move in smaller circles

You see the Moon rising, just as the Sun is setting. What phase is the Moon in? Choose one:A. third quarterB. waning crescentC. first quarterD. fullE. new

D. full

The tilt of Earth's axis causes the seasons because Choose one:A. one hemisphere of Earth is closer to the Sun in summer.B. the days are longer in summer.C. the rays of light strike the ground more directly in summer.D. both a and b are correct.E. both b and c are correct.

E. both b and c are correct.

Label these important places on the celestial sphere.

Top to bottom:ADCB

Since the seasons are linked to the position of the Sun on the tilted ecliptic, it may logically follow that the seasons are caused by the tilt of the Earth's rotation axis in relation to its orbit around the Sun. How could this tilt cause such an obviously large difference in temperature throughout the course of a year? Open the AstroTour animation "The Earth Spins and Revolves." Work through the Explanation section, paying close attention during the interactive parts. Based on what you learn, click and drag the seasons to the place on the celestial sphere where you would expect the Sun to be during each season, as experienced in the Northern Hemisphere. (Note that the Southern Hemisphere will have the opposite season at that time).

summer is above the equator, spring is on the equator, winter is below the equator