Question 1

The only chemical elements that formed as the universe cooled down after the Big Bang were hydrogen,deuterium,and helium.

Accepted Answer

A) True 
 B)False

Question 2

The COBE and WMAP satellites detected fluctuations in the CBR.On average,how big were these fluctuations,and what does that tell us about the universe at a redshift of   ?

Accepted Answer

The COBE and WMAP satellites detected ti

Question 3

Where in the universe did the Big Bang take place?

Accepted Answer

A)  Near the Milky Way Galaxy 
B)  Near the Virgo cluster 
C)  Near some unknown location on the other side of the universe 
D)  Everywhere in the universe 
A)  Near the Milky Way Galaxy 
B)  Near the Virgo cluster 
C)  Near some unknown location on the other side of the universe 
D)  Everywhere in the universe

Question 4

What does the value of   ,the scale factor,tell us?

Accepted Answer

The scale factor tel

Question 5

To be a standard candle an object must have a constant

Accepted Answer

A)  lifetime. 
B)  brightness. 
C)  luminosity. 
D)  distance. 
A)  lifetime. 
B)  brightness. 
C)  luminosity. 
D)  distance.

Question 6

Astronomers use galactic redshift as a measure of

Accepted Answer

A)  gravity. 
B)  distance. 
C)  velocity. 
D)  mass. 
A)  gravity. 
B)  distance. 
C)  velocity. 
D)  mass.

Question 7

The value of the scale factor RU depends inversely on the value of redshift z.

Accepted Answer

A) True 
 B)False

Question 8

What do astronomers mean when they say that the universe is homogeneous?

Accepted Answer

A)  All stars in all galaxies have planetary systems just like ours. 
B)  The universe looks the same no matter where you look. 
C)  Galaxies are generally distributed similarly throughout the universe. 
D)  Generally speaking,there is little difference between conditions on Earth,in the Sun,or in outer space. 
A)  All stars in all galaxies have planetary systems just like ours. 
B)  The universe looks the same no matter where you look. 
C)  Galaxies are generally distributed similarly throughout the universe. 
D)  Generally speaking,there is little difference between conditions on Earth,in the Sun,or in outer space.

Question 9

The existence of the cosmic background radiation tells us that the early universe was

Accepted Answer

A)  much hotter than it is today. 
B)  much colder than it is today. 
C)  composed entirely of radiation at early times. 
D)  composed entirely of stars at early times. 
A)  much hotter than it is today. 
B)  much colder than it is today. 
C)  composed entirely of radiation at early times. 
D)  composed entirely of stars at early times.

Question 10

It is possible for a galaxy to have a recessional velocity greater than the speed of light.

Accepted Answer

A) True 
 B)False

Question 11

The spectrum of a galaxy is observed to have an H$\alpha$ emission line at a wavelength of 928.7 nm.What is its redshift? Note that the rest wavelength of the H$\alpha$ emission line is 656.3 nm.

Accepted Answer

The answer of The spectrum of a galaxy is observed...

Question 12

Astronomers have known that galaxies are separate entities outside of our own for roughly the last

Accepted Answer

A)  30 years. 
B)  90 years. 
C)  150 years. 
D)  300 years. 
A)  30 years. 
B)  90 years. 
C)  150 years. 
D)  300 years.

Question 13

If you found a galaxy with an   emission line that had a wavelength of 756.3 nm,what would be the galaxy's redshift? Note that the rest wavelength of the   emission line is 656.3 nm.

Accepted Answer

A)  0.01 
B)  0.05 
C)  0.10 
D)  0.15 
A)  0.01 
B)  0.05 
C)  0.10 
D)  0.15

Question 14

Assuming a Hubble time of 13.6 billion years and a constant rate of expansion of the universe,what was the scale factor   of the universe 10.2 billion years ago (compared to today)?

Accepted Answer

A)  0.25 
B)  0.50 
C)  0.67 
D)  0.75 
A)  0.25 
B)  0.50 
C)  0.67 
D)  0.75

Question 15

Hubble's constant,   ,represents

Accepted Answer

A)  the rate of expansion of the universe. 
B)  the speed at which galaxies are moving away from us. 
C)  the time it takes a galaxy to move twice as far away from us. 
D)  the size of the universe. 
A)  the rate of expansion of the universe. 
B)  the speed at which galaxies are moving away from us. 
C)  the time it takes a galaxy to move twice as far away from us. 
D)  the size of the universe.

Question 16

The spectrum of a galaxy is observed to have an H$\alpha$ emission line at a wavelength of 856.3 nm.What is its distance if the Hubble constant is 22 km/s/Mly? Note that the rest wavelength of the H$\alpha$ emission line is 656.3 nm.

Accepted Answer

The answer of The spectrum of a galaxy is observed...

Question 17

The Hubble Space Telescope can be used to study galaxies at a redshift equal to 2.How much has the universe expanded since that redshift?

Accepted Answer

The expansion factor at @#IMG-DLM& is @#IMG-DLM& .

Question 18

If you found a galaxy with an H$\alpha$ emission line that had a wavelength of 756.3 nm,what would be the galaxy's distance if the Hubble constant is 22 km/s/Mly? Note that the rest wavelength of the H$\alpha$ emission line is 656.3 nm.

Accepted Answer

A)  1,120 km/s 
B)  2,080 km/s 
C)  6,070 km/s 
D)  8,500 km/s 
A)  1,120 km/s 
B)  2,080 km/s 
C)  6,070 km/s 
D)  8,500 km/s

Question 19

If the density of normal matter,such as protons and electrons,were higher in the early universe,would there have been more or less   made in the Big Bang?

Accepted Answer

If there were more protons and

Question 20

If the spectrum of a distant galaxy is observed to have a calcium K absorption line that occurs at a wavelength of 500.4 nm,what is this galaxy's distance if the rest wavelength of this absorption line is 393.4 nm?

Accepted Answer

A)  950 Mly 
B)  1,800 Mly 
C)  2,300 Mly 
D)  3,700 Mly 
A)  950 Mly 
B)  1,800 Mly 
C)  2,300 Mly 
D)  3,700 Mly

Exam 18: Our Expanding Universe

The only chemical elements that formed as the universe cooled down after the Big Bang were hydrogen,deuterium,and helium.

The COBE and WMAP satellites detected fluctuations in the CBR.On average,how big were these fluctuations,and what does that tell us about the universe at a redshift of ?

Where in the universe did the Big Bang take place?

What does the value of ,the scale factor,tell us?

To be a standard candle an object must have a constant

Astronomers use galactic redshift as a measure of

The value of the scale factor RU depends inversely on the value of redshift z.

What do astronomers mean when they say that the universe is homogeneous?

The existence of the cosmic background radiation tells us that the early universe was

It is possible for a galaxy to have a recessional velocity greater than the speed of light.

The spectrum of a galaxy is observed to have an H α\alphaα emission line at a wavelength of 928.7 nm.What is its redshift? Note that the rest wavelength of the H α\alphaα emission line is 656.3 nm.

Astronomers have known that galaxies are separate entities outside of our own for roughly the last

If you found a galaxy with an emission line that had a wavelength of 756.3 nm,what would be the galaxy's redshift? Note that the rest wavelength of the emission line is 656.3 nm.

Assuming a Hubble time of 13.6 billion years and a constant rate of expansion of the universe,what was the scale factor of the universe 10.2 billion years ago (compared to today)?

Hubble's constant, ,represents

The spectrum of a galaxy is observed to have an H α\alphaα emission line at a wavelength of 856.3 nm.What is its distance if the Hubble constant is 22 km/s/Mly? Note that the rest wavelength of the H α\alphaα emission line is 656.3 nm.

The Hubble Space Telescope can be used to study galaxies at a redshift equal to 2.How much has the universe expanded since that redshift?

If you found a galaxy with an H α\alphaα emission line that had a wavelength of 756.3 nm,what would be the galaxy's distance if the Hubble constant is 22 km/s/Mly? Note that the rest wavelength of the H α\alphaα emission line is 656.3 nm.

If the density of normal matter,such as protons and electrons,were higher in the early universe,would there have been more or less made in the Big Bang?

If the spectrum of a distant galaxy is observed to have a calcium K absorption line that occurs at a wavelength of 500.4 nm,what is this galaxy's distance if the rest wavelength of this absorption line is 393.4 nm?

Why Learn Astronomy

Patterns in the Skymotions of Earth

Gravity and Orbitsa Celestial Ballet

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Gravity Is More Than Keplers Laws

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

A Run-Of-The-Mill G-Type Starour Sun

Star Formation and the Interstellar Medium

Stars in the Slow Lanelow-Mass Stellar Evolution

Live Fast,die Younghigh-Mass Stellar Evolution

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

The Origin of Structure

Life

Filters

The value of the scale factor R_U depends inversely on the value of redshift z.

The spectrum of a galaxy is observed to have an H $\alpha$ emission line at a wavelength of 928.7 nm.What is its redshift? Note that the rest wavelength of the H $\alpha$ emission line is 656.3 nm.

The spectrum of a galaxy is observed to have an H $\alpha$ emission line at a wavelength of 856.3 nm.What is its distance if the Hubble constant is 22 km/s/Mly? Note that the rest wavelength of the H $\alpha$ emission line is 656.3 nm.

If you found a galaxy with an H $\alpha$ emission line that had a wavelength of 756.3 nm,what would be the galaxy's distance if the Hubble constant is 22 km/s/Mly? Note that the rest wavelength of the H $\alpha$ emission line is 656.3 nm.