Chapter 1: Thinking like an astronomer

Question 1

Which direction does the Sun move as the year progresses from winter to summer?

Answer 1

North

Question 2

During the summer solstice, the sun rises and sets farthest in what direction?

Answer 2

North

Question 3

During the winter solstice, the sun rises and sets farthest in what direction?

Answer 3

South

Question 4

Define the universe:

Answer 4

everything; the entirety of space and time

Question 5

Define a galaxy:

Answer 5

a massive system of stars (and other stuff) that exists inside the universe

Question 6

Define a solar system:

Answer 6

a star and its surrounding planets, comets, asteroids, etc… that exists inside a galaxy

Question 7

Name the 8 planets of our solar system:

Answer 7

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune

Question 8

What is our cosmic address?

Answer 8

Earth, Solar system, milky way galaxy, local group, virgo supercluster

Question 9

What do light-years (ly) measure?

Answer 9

the distance light travels in 1 year

Question 10

How long does it take light to travel Earth’s circumference?

Answer 10

1/7 second

Question 11

How long does it take light to travel from Earth to the moon?

Answer 11

1.25 seconds

Question 12

How long does it take light to travel from Earth to the sun?

Answer 12

8.3 minutes

Question 13

How long does it take light to travel the diameter of Neptune’s orbit?

Answer 13

8.3 hours

Question 14

How long does it take light to travel from the solar system to the nearest star?

Answer 14

4.2 years

Question 15

How long does it take light to travel the diameter of the milky way galaxy?

Answer 15

100,000 years

Question 16

How long does it take light to travel between the milky way galaxy and the andromeda galaxy?

Answer 16

2.5 million years

Question 17

How long does it take light to travel the universe?

Answer 17

13.8 billion years

Question 18

What is the speed of light? (in km/s)

Answer 18

300,000 km/s

Question 19

Stars generate energy by what process? This process creates ____ elements. Dying stars eject those elements into space. New stars and planets (and humans) form.

Answer 19

nuclear fusion, heavier elements

Question 20

Define the scientific method. What is the order of things?

Answer 20

a systematic way of testing new ideas or explanations

-observation, hypothesis, prediction, test

Question 21

What is a hypothesis?

Answer 21

a testable explanation of the observation

Question 22

What happens when your hypothesis has been falsified?

Answer 22

it has been proven incorrect

Question 23

When does a hypothesis become a theory?

Answer 23

as continuing tests support a hypothesis by failing to disprove it, scientists come to accept the hypothesis as a theory

Question 24

What is the cosmological principle?

Answer 24

The testable assumption that the same physical laws that apply here and now also apply everywhere and at all times.

Question 25

What is a physical law?

Answer 25

theories that have become very well tested and are of fundamental importance.

Question 26

What is Occam’s razor?

Answer 26

when we are faced with two hypotheses that explain all the observations equally well, we should use the one that requires the fewest assumptions, until we have evidence to the contrary

Question 27

In terms of graphs, which variable is usually represented on the x-axis and which one is on the y-axis?

Answer 27

x-axis: independent variable

y-axis: dependent variable