Galaxies Flashcards
(93 cards)
1
Q
What are galaxies?
A
very large collections of stars
2
Q
How many galaxies does the universe contain
A
billions
3
Q
How are galaxies distributed
A
Galaxies are NOT distributed in the universe
4
Q
What galaxy is the Earth located in?
A
In the milky way galaxy
5
Q
What holds stars and galaxies together?
A
Gravity
6
Q
What is dark matter
A
matter that doesn’t emit any light in any wavelength
7
Q
How much of the universe is dark matter?
A
90%
8
Q
Do scientists know what gravity is made of?
A
NO… Freaky!
9
Q
Name the types of galaxies
A
Spiral vs. barred spiral
Elliptical
Irregular
10
Q
What are the nuclei and Arms of Galaxies
A
A
B
C
11
Q
A- nuclei and arms of galaxies
A
large nucleus with arms tightly wound
12
Q
B nuclei and arms of galaxies
A
medium nucleus with arms not wound as tight
13
Q
C nuclei and arms of galaxies
A
small nucleus with arms loosely wound
14
Q
What are normal spiral facts
A
Bright disk with prominent nucleus
some appear tightly wound
stars range in all ages
15
Q
What type of galaxy do we live in?
A
Spiral Barred galaxy (SBc)
16
Q
The diameter of the Milky way
A
100,000 light years
17
Q
How many stars are in the milky way?
A
400 billion
18
Q
How often does the sun orbit the galaxy?
A
once every 250 million years
19
Q
What group of galaxies are we apart?
A
Local group
20
Q
How many galaxies are in the local group
A
3 large galaxies
30 small galaxies
21
Q
What is the largest galaxy in our group?
A
Andromeda M31
22
Q
Elliptical Galaxies
A
E0 (spherical) - E7 (very elliptical)
23
Q
Types of star in Elliptical galaxies
A
Giants
Neutrons
Main sequences
White dwarfs
24
Q
How much gas and dust is in an elliptical galaxy?
A
Little remaining dust and gas
25
Age of elliptical stars
usually old
26
Age of irregular stars
stars are typically young
27
Types of stras in Irregular galaxies
Nebulas
Proto-stars
Main sequences
Red Dwarfs
28
How much gas and dust is in irregular galaxies
lots of gas and dust present
29
Explain the Big Bang Theory
- 14 billion years ago
- extremely hot and dense
- cooled and atoms started to form and then the stars formed and the gravity pulled stars in galaxies
30
Is the universe expanding?
The universe is continuing to expand even today
31
Edwin Hubble
First to show that the universe is expanding.
1889-1953
- Hubble telescope in honor
32
How did Hubble show the expansion of the universe
Used the Doppler effect to show that galaxies are moving away from us
33
Magnitude
the brightness of an object/star
34
Apparent Magnitude
how bright an object appears to be (distance not accounted for)
35
Absolute Magnitude
Brightness an object would have if placed 10 parsecs away
36
What is 1 parsec
3.26 light years
37
1 light year
5,880,000,000,000 miles
38
What do all stars start out as?
Nebula
| Protostar
39
Nebula
cloud of gas and dust
40
Nebula gravitational pull
causes it to be unstable which causes fragmentation to occur
41
Protostar
Particles move closer together
temperature increases
fusion eventually starts and now considered a star
42
Main Sequence Stars
when fusion and gravity are equal... now its a main sequence star
Fusion is with hydrogen gas
43
What happens to a dying star?
Hydrogen runs out
Core collapses
Star explodes
44
Red Giant
fusion of helium gas
45
What is light made of
Electric component & Magnetic component
46
How do EM waves differ
Wavelength
Frequency
Energy
47
Wavelength
the distance from one crest or trough to the next crest or trough
48
Frequency
The number of waves per second
49
What is frequency measured in?
hertz
50
Energy
Hot objects create high energy and short waves and cool objects create low energy and long waves
51
What will be the frequency if you have a long wavelength?
Short frequency
52
What will be the energy if you you have an increased wavelength
increased energy
53
What will be the temperature if you have an increased energy
increased temperature
54
Radiation
all EM waves travel at the speed of light
| travels through space
55
Radio Waves
```
AM= football length
FM= house length
```
56
Microwaves
baseball length
| used for TV and cell phones
57
Infrared Waves
detects heat
58
Visible Waves
used in lasers
| Used in bar code scanners, TV monitors and fiber optics
59
Why do we only see visible light?
our nervous system can only detect radiation in the visible range
60
Ultraviolet waves
Sun burn
UV satellite
Sun
61
X-Ray waves
doctors transfer these to photos
used in radiation therapy
as long as a water molecule
62
Gamma Waves
shortest wavelength and most energetic of all
63
Continuous Spectrum
A hot gas under high pressure
| An unbroken band of colors whose light is visible in all wavelengths
64
Dark line spectrum
cool gas between source and observer- absorbs energy
65
Bright line spectrum
Hot gas under low pressure
| A series of lines that are unevenly spaced and are of different colors and brightness
66
What causes light
Electron transitions
67
What are electron transitions
The movement of electrons from one energy level to another
68
If an electron has a higher energy level where will its location be?
closer to the nucleus
69
What happens when electrons are bumped away from the nucleus?
energy is absorbed
70
What happens when electrons return toward the nucleus
Energy is given off as light
71
Large movement
large energy and has a short wavelength
72
Examples of large energy
X-ray and gamma ray
73
Small movement
small energy and long wavelength
74
Examples of small movement
radio and infrared
75
Doppler Shift
All lines shift up in the effected spectrum
76
What does a red doppler shift indicate?
it means that the galaxy is moving away from us
77
What does a blue doppler shift indicate?
it means that the galaxy is moving towards us
78
What happens to wavelength when approaching them
they are shorter when approaching
79
What happens to wavelength when receding?
they are longer when receding
80
What do Red Giant Stars used for fusion
Use helium for fusion energy
81
Red Giant stars more information
```
Outer layers are much cooler
helium eventually runs out
core collapses and heats up
can create a planetary nebula around it form its collapse
carbon forms in core star
```
82
What is the start of the life cycle of a star
Stellar nebula
83
Life cycle of a star starting at average star
average star
Red giant
Planetary Nebula
white dwarf
84
Life cycle of a star starting with massive star
Massive star
Red Supergiant
Supernova
Neutron star or Black Hole
85
White Dwarf
Used up its total supply of energy (hydrogen and helium)
Collapsed from its own gravity
Giving off heat- no fusion
Half the size of earth
86
Black Dwarf
a dead star that does not radiate heat
No energy generated
No star in our galaxy is this old
87
What happens to a massive star?
it becomes a super giant
88
Super Giant Example
Aldebaran in the constellation Taurus
| Got this big because of its large Mass
89
Super Giants
Fusion of Helium
Starts to run out of energy
Starts to collapse in on itself and creates a new gravity and then explodes!
1000 times brighter than the sun
90
Supernovas
can outshine an entire galaxy
only lasts a few seconds in this stage
will collapse in on itself because of a lack of mass
91
What happens when a supernova mass collapses
When this happens it is called a neutron star
92
Neutron star
collapsed supernova
made of neutrons
rotates at high speeds, sometimes called a pulsar
93
Black hole
collapse is violent
| Gravitational pull is so strong that light can't escape
