Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Astronomy > Exam 4 > Flashcards

Exam 4 Flashcards

1
Q

Bright, sphere-shaped region of stars that occupies the central few thousand lightyears of the milky way galaxy

A

Galaxy’s Bulge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Gas and Dust that lies between the stars in the Milky Way Galaxy

A

Interstellar medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Two smaller galaxies that orbit the Milky Way Galaxy

A

Magellanic clouds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The continuous recycling of gas in the galactic disk between stars and the interstellar medium…

A

Star-Gas-Star Cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is 2% of the mass of the milky ways interstellar medium?

A

Elements heavier than hydrogen and helium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Subatomic particles that travel close to the speed of light

A

Cosmic Rays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the most abundant chemical in molecular clouds?

A

H2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does interstellar dust mostly consist of?

A

Microscopic particles of carbon and silicon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

A cloud of hydrogen and helium that contracts to become a galaxy

A

Protogalactic Galaxy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Most stars in the Milky Way Galaxy are…

A

very old

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

A colorful cloud of gas that glows because it is heated by light from nearby hot stars

A

Ionization Nebula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Most common form of gas in the disk of the Milky Way Galaxy

A

Atomic Hydrogen Gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What law of nature explains why the galaxy began to rotate rapidly and flattened out as it shrunk in size?

A

Law of Conservation of Angular Momentum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The circular but relatively flat portion of the galaxy

A

Disk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

First Portion of the galaxy to form

A

Halo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

A tightly packed group of a few hundred thousand, very old stars

A

Globular Cluster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Stands out in a photo of a galaxy because it shines brightly with light from massive young stars and glowing clouds of gas and dust

A

Spiral Arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Stars orbiting in the _____ near the galaxy’s center can have orbits highly inclined to the galactic plane

A

Bulge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Estimated number of galaxies in our observable universe

A

100 Billion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

NOT one of the major clusters

A

Global Clusters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Dark energy has been hypothesized to exist in order to explain…

A

Observations of galaxies suggesting the expansion of the universe is accelerating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Dark Matter in inferred to exist because…

A

We can observe it’s gravitational influence on visible matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Strong evidence for the existence of dark matter comes from the observations of…

A

Orbital Periods (rotation curve) of stars in the milky way galaxy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is meant in cosmology by “critical density”?

A

The density that determines whether the universe expands forever or re-collapses

25
Why do we think galactic collisions were more common in the past?
The early universe was smaller, therefore galaxies were closer to each other in the past
26
What do we think lies at the center of the universe?
Cosmology tells us there is no center
27
Which type of galaxy contains very little interstellar gas?
Elliptical
28
What does the big bang theory predict could be seen today?
Radiation that is coming from all directions in space, and has been red-shifted to microwave spectrum
29
Using powerful telescopes to look back in time over 10 billion years, what did we discover the most distant (youngest) galaxies to look like?
Very Irregular
30
What is the rotation curve of a spiral galaxy?
A plot of the rotation (orbital) speeds of its stars vs. distance from the center of the galaxy
31
{TRUE OR FALSE} When we look at the cosmic microwave background radiation, we are looking further into space (back in time) than when we loom at the farthest galaxies
True
32
Matter fall into super-massive black holes in the centers of some galaxies is thought to be the source of:
Active Galactic Nuclei, Strong Radio Sources, Giant jets that shoot far into space, and Quasars
33
{TRUE OR FALSE} A main goal of the Hubble Space Telescope was to measure the Hubble Constant, H0 as 1/H0 to give us the best estimate of the current age of the universe
True
34
About how old was the universe when galaxies appeared?
1 Billion Years Old
35
A light source of known luminosity
Standard Candle
36
Where do we think fark matter primarily resides in our galaxy?
In the Halo region and it's surroundings
37
Why have astronomers recently determined that there must be an additional strong force, termed "dark energy" acting on the universe?
They have measured an unexpected acceleration in the expansion
38
{TRUE OR FALSE} The existence of dark matter has been established by observing it with specialized dark matter telescopes
False
39
What is currently believed to make up the majority of dark matter?
WIMPS
40
About what age is the universe?
14 Billion Years Old
41
What TWO things happen when galaxies collide?
Strong gravitational forces will distort the shape of the galaxy and Molecular gas clouds will collapse. creating star bursts that enhance star formation
42
Cosmological red-shift that all distant galaxies exhibit is result of...
The expansion of the Universe
43
{TRUE OR FALSE} The sun is a bulge star, born near the center of the galaxy
False
44
What do we mean when we talk about the "expansion of the universe"?
That space itself is expanding
45
{TRUE OR FLASE} Starburst galaxies have been forming stars at the same furious pace since the universe was about a billion years old
False- Bursts of star formation would use up all the gas in a galaxy in a much shorter period of time than the age of the universe
46
What holds the Local Group of galaxies together?
The gravitational force
47
The luminosity of a Quasar is generated in a region about the radial size of...
Our solar system
48
How long does light from the neatest star (not including the sun) take to reach us?
About 4 years
49
What doe we think lies at the center of the Milky Way?
A massive black hole
50
How did Edwin Hubble first prove that the strange looking spiral nebulae were really distant galaxies?
He used bright Cepheid variables in them to measure their distances
51
When we look at a very distant galaxy, billions of light years away, we see it...
When it was younger than now
52
How long does it take for light to cross the milky way?
Around 100,000 years
53
Where are most of the milky ways globular clusters found?
In the halo
54
Where would you be most likely to find an ionization nebula?
In the disc
55
The orbits of halo and bulge stars are special because...
Their orbits are randomly inclined to the disk of the galaxy
56
Currently, where are stars born in the Milky Way?
Density waves in the disc spiral arms
57
Which form of radiation passes most easily through the disk of the Milky Way?
Infrared Light
58
How many stars do we think there are in our Milky Way Galaxy?
100 Billion
59
Why do disc stars bob up and down as they orbit the galaxy?
Because the gravity of other disc stars pull them towards the disc

Astronomy (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions