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Astronomy > Midterm 1 > Flashcards

Midterm 1 Flashcards

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1
Q

What is the Doppler effect?

A

Way of measuring speed of galaxy. The further away galaxies are, the faster they seem to be moving (Hubble’s law)

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2
Q

What was significant of Doppler effect?

A

Found out the universe was expanding like a balloon. Indicates that the universe was zero size at one point.

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3
Q

How old is the universe?

A

13 Gyr (13 billion year)

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4
Q

How old is the earth?

A

4.5 Gyr

Sun and planets all formed when the universe was already 8.5 billion yo.

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5
Q

What did James jeans discover?

A

Squeeze a balloon and let it go. If we do this with a big balloon, at one point if it is as big as the solar system, something funny occurs!

It won’t bounce back to its original size but it will continue to collapse.

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6
Q

How do galaxy clusters grow?

A

By colliding with each other.

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7
Q

How are stars formed?

A

Gas is super dense and then collapses on itself.

As the gas gets denser, the angular momentum gets faster and materials move closer to the rotation axis.

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8
Q

What are disks?

A

They show how planets are formed. The radius of planets change changes and planets did not form where we now see them.

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9
Q

What is binary accretion?

A

Dust particles are emitted from forming stars and aggregate, get bigger and bigger over time.

1 km- hold particles with gravity that don’t have to be sticky

Grains stick together, forming plantesimals

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10
Q

How did giant planets/ Jovian planets form?

A

10 M earth cores

  • attract hydrogen and helium
  • form from massive cores with strong enough gravity to hold in gases
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11
Q

When does planet making process end?

A

When no more material is there to pick up.

  • Uranus and Neptune’s Disk was less dense so collision between dust particles took longer to form
  • gas is held for a little amount of time and leaks away which is why U and N are newer than other gas giants Jupiter and Saturn
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12
Q

What is the equation that explains Star formation?

A

Force of gravity > force of gas pressure

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13
Q

What is late heavy bombardment?

A

Theory for what occurred due to craters on moon being 3.8 Gyr.

Resonance was thought to have occurred bw Jupiter and Saturn

  • thus dislodgment of 99 percent of comets in the Kuiper belt
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14
Q

Resonance

A

If force is applied in unequal phase, then this occurs.

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15
Q

Origin of asteroids

A
  • leftover plantesimals
  • fragmentation from protoplanets
  • many crashed into planets or ejected outside solar system
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16
Q

Comets

A

Come from Kuiper belt

- fluffy and survivors of early stages of solar system ( dust accumulation)

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17
Q

Why is angular momentum significant?

A

It is conserved and interstellar gas becomes dense and how stars like the sun are formed.

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18
Q

Three kinds of energy

A

1) kinetic energy (motion)
2) potential energy (stored)
3) radiant energy (light)

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19
Q

Law of energy conservation

A

Energy can be conserved in different forms but cannot he created nor destroyed.

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20
Q

Conservation of energy causes ___

A

Heating

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21
Q

Newton’s laws

A

1) velocity of object won’t change unless force applied
2) force = mass x acceleration
3) for every action there is an equal and opposite reaction

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22
Q

Kepler’s laws

A

1) planets move in elliptical orbits around the sun
2) equal areas are swept in equal times
3) period 2= distance 3

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23
Q

Newton and Keplers laws allow us to do what?

A

Calculate mass of the sun

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24
Q

How old is the sun

A

10 ^10 years

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25
How does sun make heat?
Nuclear fusion - 2 nuclei at high temp to create new atom which releases energy - e=mc2 shows energy and mass are related. Mass decreases after fusion and energy comes out (gamma rays) - couple billion hydrogen bombs going off for a long time
26
4 forces in nature
1. Gravity 2. Strong 3. Weak 4. Electromagnetic
27
Why doesn’t sun collapse?
Hydrostatic equilibrium. Internal hot gas while pressure pushes outwards.
28
How long does it take for the light in the middle of the sun take to get to the edge?
10 million years- - random walk path
29
What are sun spots?
- magnetic fields. They help us determine the period cycle of the sun - dark because cooler than things surrounding it - granulation occurs because of convection
30
What is corona
Outer atmosphere of the sun! - it expands throughout the solar system - it makes auroras
31
CME (Mass ejection)
- explosion on sun's surface that is dangerous to astronauts but earth's magnetic field saves us - can cause electromagnetic flux
32
Sun is a good __
conductor - atoms are free to move and electrons from hydrogen are stripped. This causes sun to rotate differentially and the north and south poles reverse.
33
What does magnetic friction refer to?
Magnetic fields can't move easily through conducting material. - sun spots are the same way. Magnetic field of sun spots vary within and between cycles because of conductive nature magnet travelling through copper example.
34
What is the Maunder Minimum?
- correlated to cold times in Europe - "Little Ice Age" - Solar MF diagram aligns with minimum cycle during this time
35
Who was Farraday and what did he do
- couldn't do math, but great experimenter | - discovered electromagnetism and things that make modern day possible
36
In regard to their cycles, sun spots and cosmic rays have an ____ relationship
inverse
37
Space race speech by kennedy
Kennedy says "Time to take long strides" and says putting a man on the moon would be a sign of being better than other nations
38
1961-1962 was when
US had so many failures one after the other
39
What was the first softlander on the moon?
Lunar Surveyor (1966)
40
Describe the Saturn V
Most powerful machine ever built (150 GW). Most of the rocket is the fuel. Has 5 different parts and all relate to different stages
41
Most important measurement from Apollo was
Age of the moon. Radioactive decay (Called "fission") is when one element decays into another.
42
Apollo showed that the moon is
4. 6 Gyr old. - moon is iron deficient relative to earth - formed from impact by Mars-shaped thing - Earth core formed before this impact - isotopic similarities
43
Origin of the moon theories
a) formed by spin-out from a rapidly rotating Earth (Fission into a binary) b) moon formed indpeendently but was captured by Earth c) Moon formed from impact by large body****
44
Crater vs. Age relation
This curve is assumed to apply through the solar system | - counting craters = estimate of age
45
Temperature is
- measure of random motion within a material. The higher the temperature the more random motion
46
Plate motions are driven by
convection of the mantle, which is itself caused by heat escaping from the core
47
ascending material is deflected sideways by the
lithosphere, and drags the plates horizontally
48
What are mantle plumes?
Hot rock that floats through the mantle and punches through the surface.
49
theory of pangea spreading apart
plumes may be responsible for this
50
outer-> inner! Name the layers of the earth!
Mantle -> Metallic core -> Inner core (solid)
51
Mercury surface
- Earth is more rocky - almost all Iron - bigger solid core - theory is that mercury was very similar at one point, but massive impact
52
Mercury has a global network of ___
ridges. They go around from shrinkage due to cooling.
53
Venus surface
- Almost same size and mass and density as earth - surface hidden by clouds - no obvious plates - pancakes are there! yummy :) from volcanic extrusions - older than earth - no global MF
54
Why aren't there plate tectonics or MF's on Venus?
- maybe because the crust is too thick to be subducted | - rotates very slowly! and rotation leads to MF
55
Mars surface
10% mass, 50% radius - frozen river channels and salty water slope streaks - possible home for life
56
Behind mars we find the ____
Asteroid Belt - ring-like distribution of asteroids between mars and Jupiter - Parent bodies of meteorites - their orbits provide clues about formation of solar system
57
Dark asteroids are dark because
- they absorb a significant amount of light | - they reflect very little light (3-5% reflective)
58
Light asteroids
- absorb little light | - reflect a significant amount of light
59
Ceres
- largest asteroid on the main belt - total mass is around mass of earth/2000 ( < M moon/20) - most of the mass is in large objects
60
Calculating mass of asteroids through
Binary systems and Newton + Kepler
61
Effects of Jupiter on Asteroids
- stirs up their orbit - scatters their asteroids out, and decreases total mass - 99.9 percent scattered away and prevented substantial planet from forming between mars and jupiter
62
Trojan Asteroids
- orbit beyond the asteroid belt in jupiter's orbit - less studied - held in place by gravity of the sun and jupiter - could be captured kuiper belt objects
63
Near Earth Asteroids
- cross orbit of earth | - can be nudged to hit earth or pass by
64
Importance of meteorites
- remnants from parent bodies - easily accessible - meteoroid: small debris in space - meteor: space debris heated by friction as it plunges into earth's atmosphere - meteorite: space debris that has reached the ground
65
Types of meteorites
1. primitive 2. Stony primitives 3. carbon -rich primitives
66
Solar system is how old?
4. 5 Billion years | - proven by age-dating meteorites

Astronomy (1 decks)

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