Astronomy Our Place in the Universe

Mars is about ________ from the Sun.

Jupiter is about ________ from the Sun.

The star Sirius is about _________ from the Sun.

The diameter of the Milky Way Galaxy is about ______

The distance from Earth to the Moon is _____

less than 0.01 AU, 8 light-years, 5 AU, 1.5 Au, about 100,000 light-years

1.5 AU

5 AU

8 light-years

about 100,000 light-years

less than 0.01 AU

Which of the following has your "cosmic address" in the correct order?

A) you, Earth, solar system, Local Group, Local Supercluster, Milky Way Galaxy

B) you, Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster

C) you, Earth, solar system, Local Group, Milky Way Galaxy, Local Supercluster

B

The distance of Mars from the Sun is about 1.5 AU. How far is this in kilometers?

A. 1.5 × 150,000,000,000 km

B. 150,000,000,000 / 1.5 km

C. 1.5 × 150,000,000 km

D. 150,000,000 / 1.5 km

C

Where is our solar system located within the Milky Way Galaxy?

A. very near the center of the galaxy

B. roughly halfway between the center and the edge of the visible disk of the galaxy

C. at the far edge of the galaxy's visible disk

D. in the halo of the galaxy

B

A galaxy is ________.

A. a name for the great variety of stars.

B. a system consisting of one or a few stars orbited by planets, moons, and smaller objects

C. a collection of a few hundred million to a trillion or more stars, bound together by gravity

D. a large, glowing ball of gas powered by nuclear energy

E. another name for the universe

C

The term observable universe refers to ________.

A. the portion of the universe that is not hidden from view by, for example, being below the horizon

B. the portion of the universe that can be seen by the naked eye

C. that portion of the universe that we have so far photographed through telescopes

D. that portion of the universe that we can see in principle, given the current age of the universe

D

The farthest galaxies that modern telescopes are capable of seeing are up to

A 1 billion light-years away.

B 5 billion light-years away.

C 10 million light-years away.

D 1 trillion light-years away.

E 10 billion light-years away.

E

The Andromeda Galaxy is faintly visible to the naked eye. When you look at the Andromeda Galaxy, the retina of your eye is absorbing light that has traveled through space for ______ to reach you.

A about 250 years

B about 100,000 years

C a few minutes

D about 2 ½ million years

D

Suppose that someone in the Andromeda galaxy had a super-telescope through which they were looking at Earth right now. They would see Earth ______.

A as it was about 2 ½ million years ago

B as it is right now

C as it was about 100,000 years ago

D as it will be about 2 ½ million years from now

A

In what sense are telescopes like time machines?

A They allow us to look at a galaxy and see it as it was at many different times in the past.

B They allow us to see distant objects as they were long in the past.

C They allow us to see distant objects as they will be in the future.

D They allow us to see what Earth looked like long ago.

B

Because we live in an expanding universe, distant galaxies are farther away from us today than they were when the light we see from them started on its journey to us. So what do we mean when we say that a galaxy is 7 billion light-years away?

A Its light has taken 7 billion years to reach us.

B Its distance from us has increased by 7 billion light-years since its light started its journey to us.

C It was 7 billion light-years away when its light started its journey to us.

D It is 7 billion light-years away today.

A

Suppose we observe a galaxy that is 13 billion light-years away. Which of the following can we conclude?

A We see the galaxy as it looked when it was 1 billion years old.

B The galaxy formed before the universe was 1 billion years old.

C We see the galaxy as it looked when it was 13 billion years old.

D The galaxy is older than the Milky Way.

B

An astronomical unit is

A any large astronomical distance.

B Earth's average distance from the Sun.

C any planet's average distance from the Sun.

D none of the above.

B

The star Betelgeuse is about 600 light-years away. If it explodes tonight,

A we won't know about it until 600 years from now.

B we'll know because debris from the explosion will rain down on us from space.

C we'll know it immediately because it will be brighter than the full Moon in the sky.

D none of the above.

A

Using the ideas discussed in your textbook, in what sense are we "star stuff"?

A Movie stars and other people are all made of the same stuff, so we all have the potential to be famous.

B The overall chemical composition of our bodies is about the same as that of stars.

C We could not survive without light from our star, the Sun.

D Nearly every atom from which we are made was once inside of a star.

D

What made most of the oxygen nuclei in the solar system?

A high energy collisions of dust and cosmic rays

B the Big Bang

C stars

D our Sun

C

What do astronomers mean by the Big Bang?

A the explosion of a massive star at the end of its life

B a gigantic explosion that blew all the galaxies in the universe to smithereens

C the event that marked the beginning of the expansion of the universe

D the event that marked the birth of our solar system

C

What do we mean when we say that the universe is expanding?

A Everything in the universe is gradually growing in size.

B The average distance between galaxies is increasing with time.

C Within galaxies, average distances between star systems are increasing with time and the galaxies and galaxy clusters are, in general, receding from each other.

D The statement is not meant to be literal; rather, it means that our knowledge of the universe is growing.

B

What is nuclear fusion?

A the process of splitting nuclei to produce energy

B the process of combining lighter weight nuclei to make heavier nuclei

C a process that only occurs in nuclear bombs

D an explosion caused by putting together two volatile chemicals

E the combination of exotic nuclei of very different types of heavy elements

B

On the cosmic calendar, where every month is about 1.2 billion years long, and where the Big Bang happened on January 1, when did the Sun and Earth form?

A September

B January

C February

D December

A

Where was the Hydrogen in the universe formed?

from the dissociation of water (H2O)

in the cores of stars

in the Big Bang

in chemical reactions in interstellar space

C

By studying distant galaxies in the 1920s, Hubble made the following important discovery that led us to conclude that the universe is expanding.

All galaxies outside the Local Group are orbiting the Local Group.

All galaxies were born at the same time, and all will die at the same time.

All galaxies outside the Local Group are moving away from us, and the farther away they are, the faster they're going.

All galaxies outside the Local Group are moving away from us, and all are moving away at nearly the same speed.

All galaxies contain billions of stars, and all galaxies have spiral shapes.

C

Which of the following statements best describes what astronomers mean when they say that the universe is expanding?

All objects in the universe, including Earth and everything on it, are gradually growing in size.

The observable universe is growing larger in radius at a rate of one light-year per year.

The universe itself is not growing, but our knowledge of the universe is increasing with time.

The average distance between galaxies is increasing with time.

The average distance between stars in the Milky Way Galaxy is increasing with time.

D

Note that an observer located at the Local Raisin would see Raisins 1, 2, and 3 all move away from her during the video. What would an observer located at Raisin 2 see?

View Available Hint(s)

Raisin 1 and Raisin 3 both move toward her.

Raisin 1 moves away from her while Raisin 3 moves toward her.

Raisin 1 and Raisin 3 both move away from her.

Raisin 1 moves toward her while Raisin 3 moves away from her.

C

The table in the video shows you the speeds of Raisins 1, 2, and 3 as measured from the Local Raisin. Suppose instead that you measured speeds as seen from Raisin 2. An observer at Raisin 2 would measure __________.

View Available Hint(s)

Local Raisin speed = 6.0 cm/hr; Raisin 1 speed = 4.0 cm/hr; Raisin 3 speed = 2.0 cm/hr

Local Raisin speed = 2.0 cm/hr; Raisin 1 speed = 4.0 cm/hr; Raisin 3 speed = 6.0 cm/hr

Local Raisin speed = 4.0 cm/hr; Raisin 1 speed = 2.0 cm/hr; Raisin 3 speed = 2.0 cm/hr

Local Raisin speed = 4.0 cm/hr; Raisin 1 speed = 2.0 cm/hr; Raisin 3 speed = 4.0 cm/hr

Local Raisin speed = 2.0 cm/hr; Raisin 1 speed = 2.0 cm/hr; Raisin 3 speed = 2.0 cm/hr

C

The following statements describe ways in which the analogy might apply to the real universe. Which statements are correct?

Check all that apply.

View Available Hint(s)

A The temperature starts low and ends high in both the raisin cake and the universe.

B The raisins stay roughly the same size as the cake expands, just as galaxies stay roughly the same size as the universe expands.

C Raisin 1 is near the center of the cake, just as our galaxy is near the center of the universe.

D An observer at any raisin sees more distant raisins moving away faster, just as an observer in any galaxy sees more distant galaxies moving away faster.

E Both the raisin cake and the universe have a well-defined inside and outside.

F The average distance increases with time both between raisins in the cake and between galaxies in the univers

B C F

Based on what you've learned from the raisin cake analogy, which two properties of distant galaxies do astronomers have to measure to show that we live in an expanding universe?

View Available Hint(s)

their ages and distances

their distances and masses

their distances and speeds

their ages and masses

C

Which of the following hypothetical observations would not be consistent with what we expect in an expanding universe?

View Available Hint(s)

You discover an extremely distant galaxy that is moving away from us at 90% of the speed of light.

You discover a pair of distant galaxies that are colliding with one another.

You discover an extremely distant galaxy that is moving toward us.

C

The Moon orbits the Sun

once a year.

once a month.

once a day.

A

The mysterious Dark Energy

is slowing the expansion of the universe.

is attributed to the gravitational force of black holes.

is believed to be the dominant form of energy in the universe.

was suggested by the unexpected rotation speeds of galaxies.

C

Why don't star systems, galaxies and galaxy clusters themselves expand as the universe around them expands?

Actually, they do.

They were formed before the period of expansion began and are thus unaffected.

Their inter-gravitational attraction is strong enough to keep them bound together against the expansion of space.

Expansion pertains to the space between objects, and not the objects themselves.

C

Why do the patterns of the stars in our sky look the same from year to year?

because the stars in the constellations move so slowly-typically about the speed of a snail-that their motions are not noticeable

because the stars in the constellations are not moving

because the stars in the constellations are so far away

because the stars in the constellations all move at the same speeds and in the same directions, so they don't change their relative positions

C

How long does it take the Earth to complete one orbit around the Sun?

one week

one month

one day

one year

The time it takes Earth to orbit the Sun changes significantly from one orbit to the next.

D

How long does it take our solar system to complete one orbit around the Milky Way Galaxy?

1 million years

100 million years

230 million years

230 thousand years

10 thousand years

C

The distribution of the mass of the Milky Way Galaxy is determined by

counting the number of stars.

studying the rotation of the galaxy.

studying how stars are distributed in the Milky Way.

weighing various parts of the Milky Way.

determining the amount of gas and dust.

B

The total energy of the universe is now thought to be dominated by

the gas between the stars.

the stars within galaxy clusters and superclusters.

Dark Matter.

Dark Energy.

D

Our solar system is located about 27,000 light-years from the galactic center. How far does our solar system travel in one orbit?

100,000 light-years

170,000 light-years

85,000 light-years

54,000 light-years

B

Which of the following lies in the ecliptic plane?

Earth's equator

Earth's orbital path around the Sun

A line connecting Earth's north and south poles

A line connecting Earth and Polaris

B

In January, Earth's rotation axis points in the direction of the star Polaris. Where does it point in July?

Toward the star Polaris

Toward a star 23 ½° away from Polaris

Toward a star 47° away from Polaris

Toward the star Sirius

A

Earth rotates once each ______ on its axis and orbits the Sun once each year. The ecliptic plane is the plane defined by ______ orbit around ________.

Axis tilt of a planet is the amount that ______ is tipped relative to a line perpendicular to the ecliptic plane.

day, year, Earth, the Sun

it's axis

1. Our entire solar system orbits around the center of the _____ about once every 230 million years.

2. The Milky Way and Andromeda galaxies are among a few dozen galaxies that make up our ________ .

3. The Sun appears to rise and set in our sky because Earth ________ once each day.

4. You are one year older each time Earth _______ about the Sun.

5. On average, galaxies are getting farther apart with time, which is why we say our _______ is expanding.

6. Our _______ is moving toward the star Vega at about 70,000 km/hr.

1. Milky Way Galaxy

2. Local Group

3. Rotates

4. Orbits

5. Universe

6.Solar system