s1basic

Part A

Which of the following statements about sidereal and solar days is not true?

Hint A.1
Study Section S1.1.

ANSWER:

A solar day is approximately 4 minutes longer than a sidereal day. A solar day is the amount of time between successive appearances of the Sun on our meridian. A sidereal day is the amount of time between successive appearances of any star on our meridian. A sidereal day is the definition of a day on the Earth and a solar day is the definition of a day on the Sun.

Part B

What is the difference between a synodic month and a sidereal month?

Hint B.1
Study Section S1.1.

ANSWER:

A synodic month is our 30 or 31 day calendar month and a sidereal month is the time it takes for a cycle of the Moon's phases. A synodic month is the time it takes for a cycle of the Moon's phases and a sidereal month is our 30 or 31 day calendar month. A synodic month is based on the orbit of some planet around the Sun and a sidereal month is based on the orbit of the Moon around the Earth. A synodic month is the time it takes for a cycle of lunar phases and a sidereal month is the time it takes the Moon to orbit Earth (relative to the stars).

Part C

When we say that Jupiter is at opposition we mean that it ______.

Hint C.1
Study Section S1.1

ANSWER:

is behind the Sun as seen from Earth, so that it appears very close to the Sun in our sky. it is at the point in its orbit where it is farthest from the Sun. is at its greatest western elongation. appears on the opposite side of the sky from the Sun, so that it is on our meridian at midnight.

Part D

What kind of time can be read directly from a sundial?

Hint D.1
Study Section S1.1.

ANSWER:

mean solar time. apparent solar time. standard time. universal time.

Part E

Universal time, or UT, is ______.

Hint E.1
Study Section S1.1.

ANSWER:

another name for standard time. A timekeeping system based on careful observations of positions of stars throughout the universe. the apparent solar time in Greenwich, England. the mean solar time in Greenwich, England.

Part F

Our modern calendar is also known as ______.

Hint F.1
Study Section S1.3.

ANSWER:

the Julian calendar. the Universal Calendar (UC). the Gregorian calendar. the Metonic calendar.

Part G

Which of the following best describes the meaning of declination and right ascension?

Hint G.1
Study Section S1.2.

ANSWER:

They are used to describe the locations and distances of stars that we see in the night sky. They are terms used by astronomers to describe how the sky changes with the seasons. They are coordinates on the celestial sphere, with declination telling us the angular distance of an object from the celestial equator and right ascension telling us how far around the celestial sphere an object is located from the vernal equinox. They are coordinates on the celestial sphere that are very similar to the coordinates of altitude and direction on Earth.

Part H

The Sun's declination on June 21st is ______.

Hint H.1
Study Section S1.2

ANSWER:

+23.5 degrees. different depending on where you are on Earth. 0 degrees. -23.5 degrees.

Part I

Which of the following best describes the Tropic of Cancer?

Hint I.1
Study Section S1.2.

ANSWER:

It is the circle of latitude on Earth for which the Sun appears directly overhead at noon on the summer solstice. It is the circle of latitude on Earth for which the Sun appears to remain above the horizon for a full 24 hours on the summer solstice. It is the circle of latitude on Earth for which the Sun appears directly overhead at noon on the spring and fall equinoxes. It is the line of right ascension passing through the constellation of Cancer.

Part J

Suppose you live at latitude 40°N. Which of the following describes the path of the celestial equator through your sky?

Hint J.1
Study Section S1.2.

ANSWER:

It goes from due east on your horizon, to an altitude of 40° in the south, to due west on your horizon. It goes from due east on your horizon, to an altitude of 40° in the north, to due west on your horizon. It goes from due east on your horizon, to an altitude of 50° in the south, to due west on your horizon. It goes from due south on your horizon, to your zenith, to due north on your horizon.

Part K

Suppose it is January and the Sun remains above your horizon all day long. Where must you be located?

Hint K.1
Study Section S1.2.

ANSWER:

You must be at the North Pole. You must be at the South Pole. You must be somewhere between the Antarctic Circle and the South Pole. You must be somewhere between the Arctic Circle and the North Pole.

Part L

From a latitude of 60 degrees north during the winter, the Sun will ______.

Hint L.1
The Arctic circle is at a latitude of 66.5 degrees North.

ANSWER:

spend most of each day below the horizon. never be seen above the horizon. spend a few weeks continuously below the horizon. spend most of each day above the horizon.

Part M

If you were standing on Earth's equator, where would you look to see the North Celestial Pole?

Hint M.1
Study Section S1.3

ANSWER:

Due east. Towards the ecliptic. Directly overhead. On your horizon due north.

Part N

Suppose you know the declination of a bright star that is now crossing your meridian. What else must you measure in order to determine your latitude?

Hint N.1
Study Section S1.3.

ANSWER:

The apparent solar time. The current universal time. The star's altitude. The star's right ascension.

Part O

What is the global positioning system (GPS)?

Hint O.1
Study Section S1.3.

ANSWER:

A set of satellites orbiting the Earth, from which it is possible to compute precise locations (latitude and longitude) on the ground. A system of determining positions on the Earth by careful observations of the Sun and stars. A term used to refer to any type of celestial navigation. A system of determining positions on the Earth by receiving radio signals from many ground-based beacons.