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Flashcards in Lecture 8 Deck (34)
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1
Q

What is strange about the “disappearing star” KIC 8462852?

A

There are irregular dips in the light output, suggesting something large is coming in front of the star periodicially

2
Q

What is a Dyson sphere?

A

A suggested answer to the problem of the star dimming; a huge metal structure built to capture light

3
Q

What properties of the solar system must the formation theory explain?

A
  1. Formation of sun 2. Patterns of motion 3. exceptions 4. Existence of three types of planets 5. existence of smaller bodies
4
Q

What were the two prevailing theories?

A

Nebular and close encounter

5
Q

What was the nebular theory?

A

Theory that solar system formed when a cloud of dust collapsed

6
Q

What was the close encounter hypothesis and why was it disproved?

A

It stated that a nearby star came in and caused large chunks of debris to form the planets; but can’t be true because that is highly improbable and wouldn’t account for the different patterns of motion

7
Q

What is one example where we can see stars forming?

A

The Orion Nebula

8
Q

How does contraction produce heat?

A

Friction and radiation of collapsing

9
Q

Why should a cloud start collapsing?

A

After a cataclysmic event

10
Q

What three things happen to a spinning cloud?

A

Heating, Spinning, Flattening

11
Q

Why do collapsing clouds heat up?

A

Due to the gravitational energy

12
Q

Why do collapsing clouds spin faster?

A

Due to the change in angular momentum

13
Q

Why do collapsing clouds flatten?

A

Because as particles collide they form clumps, and this helps to organize the motion

14
Q

What three things constrain the possibility of a collapse?

A

Low density, too hot, too large

15
Q

What happens in star formation once the large cloud collapses?

A

Smaller clouds form due to various things, for example magnetic fields

16
Q

What is interesting about view T Tauri star?

A

It is embedded in a nebula

17
Q

What was the era of Heavy Bombardment?

A

The time when most craters formed

18
Q

What are Herbig Haro objects?

A

Stellar jets of gas

19
Q

Why did different types of planets form?

A

Due to the different temperatures at which compounds condense

20
Q

What is the frost line?

A

The line which marks where hydrogen compounds may start to condense

21
Q

How did the terrestrial planets form?

A

Accretion

22
Q

How did captured moons occur?

A

By random objects getting trapped in gravitational field

23
Q

How can we tell if a moon is a captured moon?

A

Usually quite small, retrograde orbit, or tiled at a funky axis, funky shape

24
Q

What are the four steps to planetary formation?

A
  1. Dust sticks together
  2. Orderly growth
  3. Runaway growth
  4. Oligarchic growth (of only certain planets)
25
Q

Why do we suspect Itokawa is a planetesimal?

A

It has two distinct chunks that seemed to have formed together

26
Q

How did the jovian planets form?

A

Ice condensed as well as other materials, and they got so big because they had a much larger area to sweep, and eventually could get even H and He to become part of their atmosphere

27
Q

Why does migration occur after planets have formed?

A

Due to friction from the dust

28
Q

What is type 1 migration?

A

Body slows down due to friction of being embedded in dust, slowly moves inward

29
Q

What is type 2 migration?

A

Body gathers up more dust, affecting the mass and therefore angular momentum of the body

30
Q

What is High Eccentricity Migration (HEM)?

A

Gravitational interaction with another body, kicking one out or in

31
Q

What happens after all formation is done?

A

Solar wind blows dust and gas away, other factors contribute to blowing the disk away

32
Q

When do comets and asteroids form?

A

After accretion, icy comets outside frost line, rocky asteroids inside frost line

33
Q

Where did Earth’s water come from?

A

Chondrites – certain chemicals delivered during Heavy Bombardement

34
Q

Why does Uranus have such a crazy tilt?

A

It got hit multiple times during Heavy Bombardment