Astronomy Flashcards
(85 cards)
1
Q
Karl Schwarzschild
A
-radius at which a stat would become “dark”
2
Q
John Michell
A
- a large enough mass in a small enough space would result in a dark star
- escape velocity > c
3
Q
Georges LeMaitre
A
- father of Big Bang theory
- backwards thinking
- universe originated at one point
- packed in a very small point
4
Q
Event horizon
A
How close you can get before light can’t escape
5
Q
What’s inside the event horizon?
A
Newton: very dense mass
Relativity: Spacetime collapses to a singularity
6
Q
Closest star to earth
A
Proxima Centauri
7
Q
Most common stars
A
Red dwarf
8
Q
Low atmospheric pressure is what type of star
A
Giant
9
Q
Sun spectral class
A
G2
10
Q
False colour image
A
An image in visible light so we can see it
11
Q
Brown dwarf
A
Failed star
- low temp
- like Jupiter
- star w/o fusion
12
Q
Solar cycle
A
- 11 years
- solar max/min
- driven by magnetic field
- variation in solar activity
13
Q
Pulsar
A
- fast spin
- forces charged particles to travel magnetic field
- neutron star
14
Q
General relativity
A
Gravity = acceleration
-Spacetime + curves/dips
15
Q
Special relativity
A
Speed of light is constant
Everything else adjusts (time dilation and length contraction)
16
Q
Blue straggler
A
Young blue star in old globular cluster
17
Q
Binary star
A
Pair of stars orbiting each other
18
Q
Globular cluster
A
Blob of stars close together
19
Q
Cepheid variable stars
A
- change brightness
- gas pressure builds up = star expands
- pressure released = star contracts
20
Q
Speed of light in a vacuum
A
300 000km/s
21
Q
Type 1a supernova
A
- white dwarf sucks H (g) from companion
- gains so much mass its unstable
- explodes
22
Q
Proof of Big Bang theory
A
CMB
Abundance of H, He, Li
Universe is expanding (hubble’s law)
Structure of universe and galaxies
23
Q
Hubble’s law
A
All galaxies are moving away from us
Farthest galaxies are moving the fastest
24
Q
Big Bang theory
A
Universe originated at a single point
25
Black holes
Singularity
Event horizon
Light can't escape
26
Singularity
Point of infinite density
| -maybe stopped with quantum mechanics
27
Fusion (main sequence)
H-> He
28
Medium mass star life
```
Nebula
Blue giant
Main sequence
~10 billion years~
Red giant
White dwarf + planetary nebula
Black dwarf (theory)
```
29
Giant star life
```
Nebula
Blue giant
~10 million years~
(H, He, C, O, Si, Fe)
BOOM
-neutron star
-black hole
```
30
Dwarf star life
```
Nebula
Blue giant
Red dwarf
~100 billion years~
White dwarf
Black dwarf (theory)
```
31
How do we know how old the universe is?
1. Radioisotopes (half lives)
| 2. Nuclear fusion (know what should be there, compare to what's actually there)
32
Parsec (in LY)
3.258LY
33
Parallax
ApParent shift in position because earth moves
| Farther = smaller parallax
34
1 LY in km
9. 5x10^12
| 9. 5 trillion
35
1 AU in km
1.495x10^8
| 150 million
36
Triangulation
Shorter distance
| Use trig
37
Doppler effect
Redshift = farther
Blueshift = closer
You know why
38
Hertzsprung-Russell diagram
```
Y axis: bright - dim (top-bottom)
X axis: O B A F G K M (left-right)
\ is main sequence
Top right is red Giants
Bottom middle are white dwarfs
```
39
Spectral classification
O B A F G K M
O: 50 000K
M: 3000K
+ # from 1-9
40
Star properties: colour
Indicates TEMP
Blue = hot
Red = cool
Determined by energy
41
Wien's law
1. Objects at different temps emit spectra that peak at different wavelengths
2. Hotter objects radiate more at any wavelength
Hot: emit most at short wavelength (blue)
Cool: emit most at long wavelength (red)
42
Blackbody
Kirchoff
- don't emit energy
- don't reflect light
- light observed is emitted (glow in the dark ish?)
43
Stars energy is determined by
Size
Age
Rate of fusion
44
Absorption spectra
When a gas cloud intercepts light and scatters certain colours
Identifies elements
Less light goes straight so these colours are darker lines
45
Emission spectra
When a gas is energized
Gas only emits certain colours
Identifies elements
46
Spectroscopy
How we study stars
| Line spectra
47
Spectrograph
Splits energy given off by a star into components
48
Apparent magnitude
How bright a star is from earth
Low # = high magnitude
Sun: -25
Faintest: +25
49
Absolute magnitude
Depends on:
1. How much light it emits
2. How far from earth
Sun: magnitude 5
'True' brightness
-luminosity
-how far from 32.6LY (10 parsecs)
50
Luminosity
Total amount of energy radiated/s
51
Star properties: categories of size/mass
Dwarf (8/100 sun)
Medium mass (sun)
Giant/supergiant (5-150x sun)
52
Radio waves (wavelength and energy)
Long wavelength
| Least energy
53
Radio waves discoveries
- magnetic fields
- radio signals
- inferometry (2 telescopes make a good pic)
- plasma clouds
- quasars discovered
54
Infrared (discoveries)
- heat (ex fire)
- passes through gas and dust
- reflected sunlight
- climate change
- changes in land cover
- trees and health of them
- remotes
- night vision
- see not visible stuff
- cooler objects
55
Ultraviolet (discoveries)
- light from ozone satellites
- young hot stars
- atmosphere
- permanent dark craters
- composition
Cassini: saw composition and aurora's of Saturn
56
X-Rays (discoveries)
- supernovae
- X-rays (bones)
- composition
- chemical structures
- hot and enerjetic objects (pulsars)
- temperature
- density
- magnetic fields
- zinc and nickel on Mars
- sun's corona
57
What uses infrared
```
ISO
Spitzer (SIRTF)
SOFIA
James Webb
Herschel
```
58
What uses X-rays
CHANDRA
RXTE (Rossi)
Suzaku
NuSTAR
59
What uses radio waves
Very large baseline array (VLBA)
HALCA
VLA
60
What uses gamma rays
Fermi
SWIFT
CGRO
HESS
61
Gamma rays (discoveries)
- passes easily through atoms
- radioactive decay
- explosions
- CME's
- composition of Mars
- pulsars/black holes
- come from top of thunderstorms
- protection for satellites
62
What uses UV
Hubble
IUE
Astro
GALEX
63
Stellar black holes
From stars
64
Supermassive black holes
In centre of galaxies
| Much bigger
65
Event horizon
Point past where nothing can return
66
Outflow
Spin of magnetic field of gas
67
Jet
Specific type of outflow
| Field line spinning (elongated tubes of plasma)
68
Frequency
Cycles/s
| Hz
69
Wavelength
Length of wave (crest-crest)
-measures in metres (nm too)
Or angstom
70
Electromagnetic wave theory
James maxwell
1873
Electro + magnetism
"Light is an electromagnetic wave composed of electric + magnetic field - exerts forces on charged particles"
71
Red light
700nm
72
Yellow light
600nm
73
Blue light
500nm
74
Violet light
400nm
75
Which type of spectrum is most useful in the study of stars
Absorption line spectrum
76
Maxwell was the first to _____
Unite magnetism and electricity
77
A star that emits most of its radiation in shorter wavelengths is what colour
Blue
78
In which class of stars would you find the greatest amount of heavier elements
Class M (red)
79
A main sequence star generates most of its energy by fusing
Hydrogen info helium
80
Which stars have the shortest lifespan
Supergiants
81
What type of star may end in a black hole
Supergiant
82
A protostar becomes a star when it begins to:
Generate energy
83
What is the speed of light
3.0x10^8 m/s
84
Binary stars end their life through
Type 1a supernova
85
As an object gets farther what do the angle measuring to it get closer to?
90
