Astro Lab Quiz 3

Difference between solar and sidereal day

. An apparent solar day is the time it takes the Sun to return to its highest point in the sky at local noon. The average time of an apparent solar day is 24 hours. . The length of an apparent solar day varies throughout the year due to the Earth's elliptical orbit & the tilt of its spin axis. . A mean solar day is a mathematical construction that addresses the shortcomings of an apparent solar day. . a sidereal day is the amount of time needed by the Earth to complete one rotation around its spin axis.

Which of the following statements concerning the Equation of Time is correct?

A. It reaches its maximum "Sun fast" value in November.

What is the shape of the Martian analemma over the course of a full year?

A. Teardrop

How long is the day in New York City (the time between sunrise and sunset) at this time of year and how high does the Sun get in the sky? Hint: The Sun is highest in the sky when it crosses the meridian. The meridian is shown on the sky for convenience.

A. The day is about 15 hours long and the Sun reaches an altitude of 72 hours.

The variable velocity of the Earth in its orbit is responsible for the Sun's changing apparent motion as it traces the analemma. The Earth's variable velocity is caused by:

A. The elliptical shape of the Earth's orbit

What is the approximate length of an apparent solar day from June 21, 2010 to June 22, 2010?

B. 24 hours 0 minutes 13 seconds

The rotation period ("day") of the Moon is

B. 27.3 Earth days

The Earth is closer to the Sun on June 21 and further from the Sun on December 21.

B. False

The shape of the analemma on Mars suggests that

B. Mars' orbit has a high eccentricity value compared to the orbit of Earth.

The vertical extent of the analemma, in angular measure is equal to

B. twice the tilt angle of the Earth's spin axis.

What is the approximate length of an apparent solar day from September 21, 2010 to September 22, 2010?

C. 23 hours 59 minutes 39 seconds

What is the approximate percentage change in the Earth-Sun distance between June 21 and December 21?

C. 3 percent

What would be the observed shape of the analemma seen from a body whose orbital eccentricity and axial tilt are both zero?

C. A point; the Sun would remain in the same position throughout the whole year.

What is the shape of the analemma over the course of a full year?

C. Figure 8

Which of the following answers about seasonal variations on Mars is correct?

C. Mars has seasons because its rotation axis is tilted with respect to the plane of its orbit.

Which of the following statements is correct?

C. The Earth's orbit is slightly elliptical and its plane is inclined to the equatorial plane of the Earth.

What is the approximate length of a sidereal day from September 21, 2010 to September 22, 2010, when measured in the units of mean solar time used by Starry Night?

D. 23 hours 56 minutes 4 seconds

What is the approximate tilt of Mars' spin axis?

D. 25 degrees

Which of the following statements is incorrect?

D. At this time of year, the Sun will reach its highest elevation in the sky for Northern Hemisphere sites.

Which of the following statements is correct on June 21?

D. The Northern Hemisphere is tilted towards the Sun.

Which of the following statements is correct?

D. The Sun is at the top of the analemma at Summer Solstice.

How many hours of daylight does New York City receive in December and how high does the Sun get in the sky at this time?

D. The day is about 9 hours long and the Sun reaches an altitude of 26 degrees.

Which of the following statements is true based upon your observations of the Earth revolving around the Sun?

D. The hemisphere tilted towards the Sun experiences summer and the hemisphere tilted away from the Sun experiences winter.

Which of the following statements explains why we experience the annual cycle of seasons in the Northern Hemisphere?

D. The tilt of the Earth's rotational axis to its orbital plane changes both the intensity of sunlight and the number of hours of sunlight received per day.

Which of the following statements is correct on December 21?

The Southern Hemisphere is tilted towards the Sun