astronomy homework 4

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

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

What causes the seasons? Choose one: A. 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. B. The Sun varies in brightness throughout the year due to cyclical changes in the number of sunspots on its surface. C. 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. D. 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.

A. 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.

No matter where you are on Earth, stars appear to rotate about a point called the Choose one: A. celestial pole. B. nadir. C. meridian. D. zenith.

A. celestial pole.

On the vernal and autumnal equinoxes Choose one or more: A. the entire Earth has 12 hours of daylight and 12 hours of darkness. B. the entire Earth has more hours of daylight than darkness. C. the Sun is located on the celestial equator. D. the Sun rises due east and sets due west. E. the Sun rises south of east and sets north of west. F. the entire Earth has more hours of darkness than daylight.

A. the entire Earth has 12 hours of daylight and 12 hours of darkness. C. the Sun is located on the celestial equator. D. the Sun rises due east and sets due west.

Why does the angle of the Sun's rays matter in regard to Earth's seasons? Choose one: A. The angle of incidence equals the angle of reflection. B. Some of the rays miss if they are striking at an angle. C. They reflect more easily if they strike at an angle. D. They are more spread out if they strike at an angle.

D. They are more spread out if they strike at an angle.

Constellations are groups of stars that Choose one: A. all have the same basic composition. B. are close to one another in space. C. are bound to one another by gravity. D. are close to one another in Earth's sky.

D. are close to one another in Earth's sky.

Where on Earth can you stand and, over the entire year, see the entire sky? Choose one: A. at either pole B. only at the North Pole C. anywhere D. at the equator

D. at the equator

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 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. B. 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. C. The Sun always appears to be in front of the same constellation. D. The Sun's apparent location with respect to the constellations is random and cannot be predicted.

A. 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.

The Sun, Moon, and stars Choose one or more: A. change their relative positions over time. B. appear in the same location in the sky everywhere on Earth because Earth is in the center of the celestial sphere. C. rise north or south of east and set north or south of west, depending on their location on the celestial sphere. D. appear to move each day because Earth rotates.

A. change their relative positions over time. C. rise north or south of east and set north or south of west, depending on their location on the celestial sphere. D. appear to move each day because Earth rotates.

The apparent path the Sun takes through the constellations over the course of a year is called the ecliptic. As seen in the figure shown, the Sun is in a different position on the ecliptic at different times of year. Assuming you are in the Northern Hemisphere, how would you expect the location of the Sun in your local sky at noon to differ from season to season? A. The Sun will appear to be closer to the southern horizon in the summer than in the winter. B. The Sun will appear to be higher above the southern horizon in the summer than in the winter. C. There should be no difference in the location of the Sun between seasons.

B. The Sun will appear to be higher above the southern horizon in the summer than in the winter.

To explain the fact that summer is hotter than winter, we can hypothesize that seasons are caused by a variable distance between the Earth and the Sun at different times of the year. Now consider the following facts that relate to this hypothesis: - The Earth's orbit is elliptical (not a perfect circle). - The Southern Hemisphere experiences opposite seasons from the Northern Hemisphere. - The intensity of light from a source is stronger closer to the source. - The Earth's closest approach to the Sun is in January. Is the hypothesis that the seasons are caused by a variable distance between the Earth and the Sun verified or falsified by the evidence? Choose one: A. It is impossible to tell because the evidence is split between for and against. B. The hypothesis is verified because some of the evidence is for it. C. The hypothesis is falsified because some of the evidence is against it.

C. The hypothesis is falsified because some of the evidence is against it.

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 orbit of the Earth around the Sun. B. The shift from day to night is caused by the Sun's orbit around the Earth. 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.

Determining what causes the seasons is not as straightforward as determining what causes day and night. We can begin by suggesting hypotheses and then testing them for their validity. Let's start with the hypothesis that the seasons are caused by a variable distance between the Earth and the Sun. Sort the observations or physical laws below according to whether they argue for or against this hypothesis.

For Hypothesis Closer light source has stronger intensity. Earth's orbit is elliptical. Against Hypothesis Earth's closest approach to Sun is in January. S and N hemispheres have opposite seasons.

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

Four special days mark the passage of the seasons. Assuming you live in the Northern Hemisphere, place these days in sequence as they occur in the year, beginning with the one that marks the official start of winter.

winter solstice, vernal equinox, summer solstice, autumnal equinox