Astronomy Final

Question 1

What are the standard units for luminosity?

Answer 1

Watts

Question 2

Purpose of adaptive optics

Answer 2

Eliminate distorting effects of atmospheric turbulence for telescopes on the ground

Question 3

How does the sun generate energy?

Answer 3

Nuclear Fusion

Question 4

What observations characterize solar maximum?

Answer 4

we see many sunspots on the sun’s surface

Question 5

When white light passes through a cool cloud of gas, we see

Answer 5

an absorption line spectrum

Question 6

How are wavelength, frequency, and energy related for photons of light?

Answer 6

Longer wavelength means lower frequency and lower energy

Question 7

HR Diagram: Cool and Dim

Answer 7

Lower right

Question 8

Overall fusion reaction by which the sun produces energy

Answer 8

4 H -> He + Energy

Question 9

Thermal Radiation:

Answer 9

radiation that depends only on the emitting objects temperature.

Question 10

Layers of the sun from center outward

Answer 10

Core, radiation zone, convection zone, photosphere, chromosphere, corona

Question 11

What is true of images captured in X-Ray telescopes?

Answer 11

Always displayed in false color

Question 12

What is the closest temperature to the CORE of the sun?

Answer 12

10 million K

Question 13

What is NOT an advantage of the Hubble Telescope over ground-based telescopes?

Answer 13

It is closer to the stars

Question 14

Luminosity

Answer 14

Total amount of light that the star radiates each second

Question 15

Gravitational Equilibrium

Answer 15

balance between the outward push of pressure and the inward pull of gravity.

Question 16

On the main sequence, stars obtain their energy by

Answer 16

converting hydrogen to helium

Question 17

HR Diagram: Largest Radii

Answer 17

Upper right

Question 18

Lowest energy- highest energy:

Different categories of electromagnetic radiation

Answer 18

radio, infrared, visible light, ultraviolet, x-ray, gamma

Question 19

Cluster ages can be determines from

Answer 19

main-sequence turnoff

Question 20

Size of the neutron star

Answer 20

City

Question 21

What temperature can helium fusion occur?

Answer 21

100 million K

Question 22

What is the closest in mass to a white dwarf?

Answer 22

the sun

Question 23

10-solar mass main-sequence star will produce a:

Answer 23

neutron star

Question 24

Planetary Nebula

Answer 24

expanding shell of gas that is no longer gravitationally held tot he remnant of a low-mass star

Question 25

What's the upper limit to the mass of a white dwarf?

Answer 25

1.4 solar masses

Question 26

How is time affected by gravity?

Answer 26

Time runs slower in places where gravity is stronger

Question 27

Stages of life for a low-mass star:

Answer 27

Protostar, main-sequence, red giant, white dwarf

Question 28

How many helium nuclei fuse together when making carbon?

Answer 28

3

Question 29

How does gravity of an object affect light?

Answer 29

Light from a massive object will be redshifted

Question 30

Pulsar:

Answer 30

an object that emits flashes of light several times per second or more, with near perfect regularity

Question 31

What is the closest in size to a white dwarf?

Answer 31

Earth

Question 32

White dwarfs are called so because

Answer 32

they are both very hot and very small

Question 33

What happens after a helium flash?

Answer 33

the core quickly heats up and expands

Question 34

How far is the sun from the center of the galaxy?

Answer 34

28,000 light-years

Question 35

How did Edwin Hubble measure the distance to the Andromeda Galaxy?

Answer 35

applied the period-luminocity relation to cepheid variables

Question 36

Diameter of the Milky way?

Answer 36

100,000 light-years

Question 37

Why do we cal dark matter "dark"

Answer 37

Emits no or very little radiation of any wavelength

Question 38

Dark Energy

Answer 38

the agent causing the universal expansion to accelerate

Question 39

Methods for determining distance: nearest to farthest

Answer 39

parallax, main-sequence fitting, cepheid variables, Tully-Fisher, Hubble's Law

Question 40

Quasar:

Answer 40

Extremely bright center of a distant galaxy, thought to be powered by a massive black hole.

Question 41

Spectral Sequence in order of decreasing temperature

Answer 41

OBAFGKM

Question 42

Hubble's Law

Answer 42

Recession velocity of a galaxy is directly proportional to its distance from us

Question 43

Most large galaxies are:

Answer 43

Spiral or lenticular

Question 44

Galaxy type most commonly found in large clusters

Answer 44

Ellipticals

Question 45

What happens when a star exhausts its core hydrogen supply?

Answer 45

Its core contracts, but its outer layers expand and the star becomes bigger and brighter

Question 46

How long does it take the sun to orbit the Milky Way Galaxy?

Answer 46

230 million years