Question 1

A light curve for a star measures how its brightness changes with

Accepted Answer

A)  time 
B)  distance 
C)  mass 
D)  radial velocity 
E)  age 
A)  time 
B)  distance 
C)  mass 
D)  radial velocity 
E)  age

Question 2

What is the closest star to the Sun?

Accepted Answer

A)  Barnard's Star 
B)  Sirius 
C)  Proxima Centauri 
D)  the Earth 
E)  we won't know the answer to this until we can travel to the stars 
A)  Barnard's Star 
B)  Sirius 
C)  Proxima Centauri 
D)  the Earth 
E)  we won't know the answer to this until we can travel to the stars

Question 3

The instrument astronomers are now using to make the most precise measurements of stellar parallax we have ever had is

Accepted Answer

A)  the 5-meter (Hale) reflector on Mt. Palomar 
B)  the Very Large Array of radio telescopes 
C)  the Compton Gamma Ray Observatory 
D)  the Gaia satellite in space 
E)  a swimming-pool sized vat of cleaning fluid deep in the shaft of a gold mine 
A)  the 5-meter (Hale) reflector on Mt. Palomar 
B)  the Very Large Array of radio telescopes 
C)  the Compton Gamma Ray Observatory 
D)  the Gaia satellite in space 
E)  a swimming-pool sized vat of cleaning fluid deep in the shaft of a gold mine

Question 4

How do astronomers know that pulsating variable stars are actually expanding and contracting in diameter?

Accepted Answer

A)  it is clear just by looking at the light curve 
B)  they discover this by looking at an H-R diagram 
C)  they can measure a regularly varying Doppler shift in the spectral lines 
D)  they can measure the star's changing pull on a companion star around it 
E)  astronomers are just guessing; at the distances of the stars, there is no way to show that stars are expanding and contracting 
A)  it is clear just by looking at the light curve 
B)  they discover this by looking at an H-R diagram 
C)  they can measure a regularly varying Doppler shift in the spectral lines 
D)  they can measure the star's changing pull on a companion star around it 
E)  astronomers are just guessing; at the distances of the stars, there is no way to show that stars are expanding and contracting

Question 5

If a star is 10 parsecs away, how long ago did the light we see from it tonight begins its journey toward us?

Accepted Answer

A)  10 years 
B)  0.1 years 
C)  10,000 years 
D)  32.6 years 
E)  6100 years 
A)  10 years 
B)  0.1 years 
C)  10,000 years 
D)  32.6 years 
E)  6100 years

Question 6

The measurement of cosmic distances was helped tremendously by the discovery, in the early part of the 20th century, that in Cepheid variable stars, the average luminosity was related to:

Accepted Answer

A)  their radial velocity 
B)  the abundance of hydrogen in their atmospheres 
C)  their distance from the Sun 
D)  the length of time they took to vary 
E)  their parallax 
A)  their radial velocity 
B)  the abundance of hydrogen in their atmospheres 
C)  their distance from the Sun 
D)  the length of time they took to vary 
E)  their parallax

Question 7

Today, astronomers can measure distances directly to worlds like Venus, Mars, the Moon, or the satellites of Jupiter by

Accepted Answer

A)  bouncing radar beams off them 
B)  using x-ray telescopes 
C)  using the Hubble Space Telescope to triangulate with 
D)  using Cepheid variable stars that lie behind the planets 
E)  sending graduate students out with very long tape measures 
A)  bouncing radar beams off them 
B)  using x-ray telescopes 
C)  using the Hubble Space Telescope to triangulate with 
D)  using Cepheid variable stars that lie behind the planets 
E)  sending graduate students out with very long tape measures

Question 8

Which type of star has the least amount of pressure in its atmosphere?

Accepted Answer

A)  main sequence stars 
B)  subgiants 
C)  giants 
D)  supergiants 
E)  you can't fool me; all stars have roughly the same pressure 
A)  main sequence stars 
B)  subgiants 
C)  giants 
D)  supergiants 
E)  you can't fool me; all stars have roughly the same pressure

Question 9

The period-luminosity relationship for Cepheid variables was discovered by

Accepted Answer

A)  John Goodricke 
B)  Henrietta Leavitt 
C)  Edward Pickering 
D)  Henry Norris Russell 
E)  Annie Cannon 
A)  John Goodricke 
B)  Henrietta Leavitt 
C)  Edward Pickering 
D)  Henry Norris Russell 
E)  Annie Cannon

Question 10

Why did it take astronomers until 1838 to measure the parallax of the stars?

Accepted Answer

A)  because most stars are too faint to see without a good telescope 
B)  because the stars are so far away that their annual shift of position in the sky is too small to see without a good telescope 
C)  because detecting parallax requires measuring a spectrum, which only became possible in the 1830's 
D)  because cepheid variable stars had not been discovered earlier 
E)  because no one before then could conceive of the Earth moving around the Sun 
A)  because most stars are too faint to see without a good telescope 
B)  because the stars are so far away that their annual shift of position in the sky is too small to see without a good telescope 
C)  because detecting parallax requires measuring a spectrum, which only became possible in the 1830's 
D)  because cepheid variable stars had not been discovered earlier 
E)  because no one before then could conceive of the Earth moving around the Sun

Question 11

The luminosity class of a star tells an astronomer

Accepted Answer

A)  whether the star is close to us or far away 
B)  whether or not the star is surrounded by planets 
C)  whether the star is a supergiant, a giant, or a main-sequence star 
D)  how long ago the star formed 
E)  none of the above 
A)  whether the star is close to us or far away 
B)  whether or not the star is surrounded by planets 
C)  whether the star is a supergiant, a giant, or a main-sequence star 
D)  how long ago the star formed 
E)  none of the above

Exam 19: Celestial Distances

A light curve for a star measures how its brightness changes with

What is the closest star to the Sun?

The instrument astronomers are now using to make the most precise measurements of stellar parallax we have ever had is

How do astronomers know that pulsating variable stars are actually expanding and contracting in diameter?

If a star is 10 parsecs away, how long ago did the light we see from it tonight begins its journey toward us?

The measurement of cosmic distances was helped tremendously by the discovery, in the early part of the 20th century, that in Cepheid variable stars, the average luminosity was related to:

Today, astronomers can measure distances directly to worlds like Venus, Mars, the Moon, or the satellites of Jupiter by

Which type of star has the least amount of pressure in its atmosphere?

The period-luminosity relationship for Cepheid variables was discovered by

Why did it take astronomers until 1838 to measure the parallax of the stars?

The luminosity class of a star tells an astronomer

Science and the Universe: a Brief Tour

Observing the Sky: the Birth of Astronomy

Orbits and Gravity

Earth, Moon, and Sky

Radiation and Spectra

Astronomical Instruments

Other Worlds: an Introduction to the Solar System

Earth As a Planet

Cratered Worlds: the Moon and Mercury

Earthlike Planets: Venus and Mars

The Giant Planets

Rings, Moons, and Pluto

Comets and Asteroids: Debris of the Solar System

Cosmic Samples and the Origin of the Solar System

The Sun: a Garden-Variety Star

The Sun: a Nuclear Powerhouse

Analyzing Starlight

The Stars: a Celestial Census

Between the Stars

The Birth of Stars and the Discovery of Planets Outside the Solar System

Stars From Adolescence to Old Age

The Death of Stars

Black Holes and Curved Space-Time

The Milky Way Galaxy

Galaxies

Active Galaxies, Quasars, and Supermassive Black Holes

The Evolution and Distribution of Galaxies

The Big Bang

Life in the Universe

Filters