Astronomy - Chapter S1

The Sun's declination on June 21st is A) +23.5 degrees B) 0 degrees C) -23.5 degrees D) different depending on where you are on Earth

A) +23.5 degrees

The amount of time between successive passes of any given star across the meridian is A) 23 hours 56 minutes B) 24 hours C) 365.25 days D) 12 years E) 26,000 years

A) 23 hours 56 minutes

Which of the following statements about sidereal and solar days is not true? A) 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 B) A solar day is approximately 4 minutes longer than a sidereal day C) A solar day is the amount of time between successive appearances of the Sun on our meridian D) A sidereal day is the amount of time between successive appearances of any star on our meridian

A) 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

Suppose you live at latitude 30°S. Which star is circumpolar in your sky? A) Alpha Centauri B) Deneb C) Spica D) Sirius

A) Alpha Centauri

Which of the following best explains why a solar day is longer than a sidereal day? A) Because Earth orbits the Sun at the same time it rotates, Earth must make slightly more than one full rotation between noon one day and noon the next B) The precession of Earth's axis gradually changes the length of the solar day while leaving the length of the sidereal day alone C) The fact that Earth's orbit is not a perfect circle causes the length of the solar day to vary during the year, so that it the solar day is sometimes longer and sometimes shorter than a sidereal day D) The Sun rotates much as the Earth does, but more slowly, so that a solar day is longer than a sidereal day

A) Because Earth orbits the Sun at the same time it rotates, Earth must make slightly more than one full rotation between noon one day and noon the next

The constellation shaped like a W is A) Cassiopeia B) Pegasus C) Canis Major D) Taurus E) Andromeda

A) Cassiopeia

Which of these stars lies closest to the north celestial pole on the celestial sphere? A) Deneb B) Alpha Centauri C) Spica D) Sirius

A) Deneb

Suppose you live at latitude 40°N. Which of the following describes the path of the celestial equator through your sky? A) It extends from due east on your horizon, to an altitude of 50° in the south, to due west on your horizon B) It extends from due south on your horizon, to your zenith, to due north on your horizon C) It extends from due east on your horizon, to an altitude of 40° in the south, to due west on your horizon D) It extends from due east on your horizon, to an altitude of 40° in the north, to due west on your horizon

A) It extends from due east on your horizon, to an altitude of 50° in the south, to due west on your horizon

Each of the following lists a constellation and a bright star. In all cases but one, the star is part of the constellation. Which one is the mismatch? A) Scorpio, Vega B) Cygnus, Deneb C) Boötes, Arcturus D) Virgo, Spica E) Auriga, Capella

A) Scorpio, Vega

Suppose you live at latitude 40°N. Which of the following describes the conditions that make a star circumpolar? A) Stars are circumpolar if they have declination > +50° B) Stars are circumpolar if they have declination > +40°. C) Stars are circumpolar if they have right ascension > 6 hr. D) Stars are circumpolar if they have right ascension < 6 hr. E) No stars are circumpolar at this latitude

A) Stars are circumpolar if they have declination > +50°

All the following statements are true. Which one explains why mean solar time differs from apparent solar time? A) The length of a solar day is not always exactly 24 hours B) Earth's rotation period is actually about 23 hours 56 minutes, not 24 hours C) Earth's axis precesses with a period of 26,000 years D) The Sun reaches the meridian at different times at different longitudes within the same time zone E) The path of the Sun through the sky depends on both latitude and date

A) The length of a solar day is not always exactly 24 hours

All the following statements are true. Which one explains why mean solar time differs from apparent solar time? A) The length of a solar day is not always exactly 24 hours B) Earth's rotation period is actually about 23 hours and 56 minutes, not 24 hours C) Earth's axis precesses with a period of about 26,000 years D) The Sun reaches the meridian at different times at different longitudes within the same time zone

A) The length of a solar day is not always exactly 24 hours

A friend says she saw a planet shining on her meridian at midnight. Which planet can you be sure that she did not see? A) Venus B) Mars C) Jupiter D) Saturn

A) Venus

What kind of time can be read directly from a sundial? A) apparent solar time B) mean solar time C) standard time D) daylight saving time E) sidereal time

A) apparent solar time

What kind of time can be read directly from a sundial? A) apparent solar time B) mean solar time C) standard time D) universal time

A) apparent solar time

The south celestial pole appears on your meridian at an altitude of 30° in the south. Where are you? A) latitude = 30°S B) latitude = 60°S C) latitude = 30°N D) latitude = 60°N E) the South Pole

A) latitude = 30°S

From a latitude of 60 degrees north during the winter, the Sun will A) spend most of each day below the horizon B) spend most of each day above the horizon C) never be seen above the horizon D) end a few weeks continuously below the horizon

A) spend most of each day below the horizon

Our modern calendar is also known as A) the Gregorian calendar B) the Julian calendar C) the Metonic calendar D) the Universal Calendar (UC)

A) the Gregorian calendar

Suppose the date is March 21 and the Sun passes through your zenith at noon. Where are you? A) the equator B) the Tropic of Cancer C) the Tropic of Capricorn D) the Arctic Circle E) the Antarctic Circle

A) the equator

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? A) the star's altitude B) the apparent solar time C) the current universal time D) the star's right ascension

A) the star's altitude

What is the hour angle of a star crossing your meridian? A) -6 hours B) 0 hours C) 6 hours D) It depends on your latitude E) It depends on the right ascension of the star

B) 0 hours

The average length of a solar day is A) 23 hours 56 minutes B) 24 hours C) 365.25 days D) 12 years E) 26,000 years

B) 24 hours

What is the difference between a synodic month and a sidereal month? A) 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 B) 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) C) 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 D) 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 Earth

B) 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)

The constellation shaped like a big square (the "great square of . . . ") is A) Cassiopeia B) Pegasus C) Canis Major D) Taurus E) Andromeda

B) Pegasus

Our calendar has leap years because A) there is one more sidereal day in a year than solar days B) a tropical year is slightly more than 365 days C) there is a difference between a sidereal year and a tropical year D) the perihelion of Earth's orbit is slowly advancing

B) a tropical year is slightly more than 365 days.

If you were standing on Earth's equator, where would you look to see the north celestial pole? A) directly overhead B) on your horizon due north C) toward the ecliptic D) due east

B) on your horizon due north

The lunar month is longer than the sidereal month because A) the Moon completes the cycle of lunar phases before it completes a full orbit around Earth B) the Moon has to complete more than one full orbit around Earth to complete the cycle of lunar phases C) the Moon orbits Earth faster than Earth orbits the Sun D) the Moon orbits Earth faster than Earth rotates E) the lunar month is based on the Moon's orbit, while the sidereal month is based on Earth's orbit

B) the Moon has to complete more than one full orbit around Earth to complete the cycle of lunar phases

Universal time, or UT, is A) another name for standard time B) the mean solar time in Greenwich, England C) the apparent solar time in Greenwich, England D) a timekeeping system based on careful observations of positions of stars throughout the universe

B) the mean solar time in Greenwich, England

The Sun is rising in the east and will be on your meridian in 2 hours. What time is it? A) 2 A.M. B) 2 P.M. C) 10 A.M. D) 10 P.M. E) noon

C) 10 A.M.

The Sun is on your meridian, and you have a UT clock that tells you it is 3 P.M. in Greenwich. What is your longitude? A) 3° west of Greenwich B) 3° east of Greenwich C) 45° west of Greenwich D) 45° east of Greenwich E) 30° west of Greenwich

C) 45° west of Greenwich

All the following statements are true. Which one explains why our calendar has leap years? A) Earth's axis precesses with a period of about 26,000 years B) There is a difference between a sidereal year and a tropical year C) A tropical year is slightly more than 365 days D) Earth's speed varies as it orbits the Sun

C) A tropical year is slightly more than 365 days

The three bright stars that make up the Winter Triangle are A) Polaris, Aldebaran, and Algol B) Polaris, Betelgeuse, and Sirius C) Betelgeuse, Procyon, and Sirius D) Betelgeuse, Rigel, and Aldebaran E) Capella, Procyon, and Sirius

C) Betelgeuse, Procyon, and Sirius

Suppose you live at latitude 40°N. Which of the following describes the path of the celestial equator through your sky? A) It goes from due south on your horizon, to your zenith, to due north on your horizon B) It goes from due east on your horizon, to your zenith, to due west on your horizon C) It goes from due east on your horizon, to an altitude of 50° in the south, to due west on your horizon D) It goes from due east on your horizon, to an altitude of 40° in the south, to due west on your horizon E) It goes from due east on your horizon, to an altitude of 40° in the north, to due west on your horizon

C) It goes from due east on your horizon, to an altitude of 50° in the south, to due west on your horizon

Which of the following statements about Betelgeuse is not true? A) It is distinctly red in color B) We now know that it is a very massive star near the end of its life C) Its Arabic name means "the demon star." D) It is one star of the three stars of the Winter Triangle, along with Procyon and Sirius E) It is the upper left shoulder star of the constellation Orion

C) Its Arabic name means "the demon star."

Which of the following best describes the meaning of declination and right ascension? A) They are coordinates on the celestial sphere that are very similar to the coordinates of altitude and direction on Earth B) They are used to describe the locations and distances of stars that we see in the night sky C) 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 D) They are terms used by astronomers to describe how the sky changes with the seasons

C) 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

What is the global positioning system (GPS)? A) a system for determining positions on the Earth by careful observations of the Sun and stars B) a system of determining positions on the Earth by receiving radio signals from many ground- based beacons C) a system for determining positions on Earth using signals from a set of satellites in Earth orbit D) a term used to refer to any type of celestial navigation

C) a system for determining positions on Earth using signals from a set of satellites in Earth orbit

Suppose you have a time-keeping device that always reads precisely 12:00 when the Sun crosses your meridian. What kind of time is this clock keeping? A) mean solar time B) standard time C) apparent solar time D) universal time

C) apparent solar time

Suppose it is January and the Sun remains above your horizon all day long. Where must you be located? A) at the South Pole B) at the North Pole C) somewhere between the Antarctic Circle and the South Pole D) somewhere between the Arctic Circle and the North Pole

C) somewhere between the Antarctic Circle and the South

Which of the following is the reason for the solar day being longer than a sidereal day? A) precession of Earth's axis B) the tilt of Earth's axis C) the combined effect of the rotation of Earth and its orbit about the Sun D) Earth year being a non-integer number of Earth days E) the non-circular orbit of Earth around the Sun

C) the combined effect of the rotation of Earth and its orbit about the Sun

Which of the following explains why navigators a few hundred years ago found it much more difficult to determine their longitude than their latitude? A) Determining longitude requires mathematical techniques that were not known at the time B) Determining longitude without modern instruments requires being able to see the Moon C) Determining longitude requires much more precise measurements of angles in the sky than does latitude D) Determining longitude requires having an accurate clock

D) Determining longitude requires having an accurate clock

Which of the following is the reason for the leap years? A) precession of Earth's axis B) the tilt of Earth's axis C) the combined effect of the rotation of Earth and its orbit about the Sun D) Earth year being a non-integer number of Earth days E) the non-circular orbit of Earth around the Sun

D) Earth year being a non-integer number of Earth days

Which of the following best describes the Tropic of Cancer? A) 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 B) It is the circle of latitude on Earth for which the Sun appears directly overhead at noon on the spring and fall equinoxes C) It is the line of right ascension passing through the constellation of Cancer D) It is the circle of latitude on Earth for which the Sun appears directly overhead at noon on the summer solstice

D) It is the circle of latitude on Earth for which the Sun appears directly overhead at noon on the summer solstice

When should we next expect to observe a transit of the Sun by Mars? A) 2010 B) 2015 C) 2140 D) Never

D) Never

Suppose you lived at Earth's equator. Which of the following statements would not be true? A) The north celestial pole is directly on your horizon, due north (with Polaris quite nearby) B) The south celestial pole is directly on your horizon, due south C) Every day of the year, the Sun is above your horizon for 12 hours and below it for 12 hours D) The celestial equator goes through your sky from due east on your horizon, through 50° altitude in the south, to due west on the horizon E) No stars are circumpolar

D) The celestial equator goes through your sky from due east on your horizon, through 50° altitude in the south, to due west on the horizon

The three stars of the Summer Triangle are A) Antares, Arcturus, and Spica B) Arcturus, Vega, and Algol C) Deneb, Spica, and Vega D) Vega, Deneb, and Altair E) Altair, Antares, and Arcturus

D) Vega, Deneb, and Altair

When we say that Jupiter is at opposition we mean that it A) is behind the Sun as seen from Earth, so that it appears very close to the Sun in our sky B) is at its greatest western elongation C) it is at the point in its orbit where it is farthest from the Sun D) appears on the opposite side of the sky from the Sun, so that it is on our meridian at midnight

D) appears on the opposite side of the sky from the Sun, so that it is on our meridian at midnight

The time between rising and setting of a star A) is always 12 hours B) depends on the star's declination C) depends on the star's right ascension D) depends on the observer's latitude E) depends on the observer's longitude

D) depends on the observer's latitude

As viewed from any place within the continental United States, noon on apparent solar time is defined as the moment when the Sun is A) directly overhead B) ante meridiem C) at a right ascension of 0 hours D) directly south

D) directly south

Suppose the date is June 21 and the Sun never sets, just touching your northern horizon at midnight. Where are you? A) the equator B) the Tropic of Cancer C) the Tropic of Capricorn D) the Arctic Circle E) the Antarctic Circle

D) the Arctic Circle

The Sun is on your meridian, and you have a UT clock that tells you it is midnight in Greenwich. What is your longitude? A) 12° west of Greenwich B) 12° east of Greenwich C) 60° west of Greenwich D) 60° east of Greenwich E) 180° of longitude from Greenwich

E) 180° of longitude from Greenwich

Based on our current Gregorian calendar, which of the following years is not a leap year? A) 2000 B) 2004 C) 2008 D) 2012 E) All of the above are leap years

E) All of the above are leap years

Which of the following best describes the Tropic of Cancer? A) It is any place where it is always very warm. B) It is another name for the equator C) It is a place where the Sun appears to remain stationary in the sky D) It is a place where the Sun is directly overhead at noon on the summer solstice E) It is a place where the Sun is directly overhead at noon on the spring equinox

E) It is a place where the Sun is directly overhead at noon on the spring equinox

Which of the following statements about sidereal and solar days is not true? A) A solar day is 4 minutes longer than a sidereal day B) A solar day represents more than 360° of rotation for Earth C) The time it takes for a star to make one circuit of our sky is one sidereal day D) The time it takes for the Sun to make one circuit of our sky is one solar day E) The time it takes for the Moon to make one circuit of our sky is one solar day

E) The time it takes for the Moon to make one circuit of our sky is one solar day

Suppose the date is March 21 and the Sun crosses your meridian at an altitude of 23.5° in the north. Where are you? A) the equator B) the Tropic of Cancer C) the Tropic of Capricorn D) the Arctic Circle E) the Antarctic Circle

E) the Antarctic Circle