Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Astronomy > Unit 2 - Planets > Flashcards

Unit 2 - Planets Flashcards

1
Q

What are Kepler’s laws?

A

1) planets have elliptical orbits around suns
2) planets must travel faster when closer to the sun
3) r^3 is directly proportional to T^2

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

Define escape velocity

A

the minimum velocity required to escape a gravitational field

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

What is the relationship between escape velocity and a planet’s ability to retain its atmosphere?

A

hotter temperatures means gas molecules travel faster, if this is faster than the escape velocity the atmosphere will escape

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

What is the nebular theory?

A

the sun and planets all had a common origin - formed from a huge cloud of interstellar gas and dust

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

What does the nebular theory provide evidence for?

A

1) all planets lie one on plane
2) the sun rotates in the same direction and most moons orbit this same way
3) most planetary orbits are near circular
4) all planets orbit in one direction and rotate in this direction

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

What is accretion?

A

the formation of planetesimals

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

Explain accretion

A

collisions between small pieces of material results in some sticking together, snowball effect causes them to increase in size and mass, increased mass means increased gravitational forces

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

Describe the composition of terrestrial planets

A

consist largely of metals and silicates since they are close to sun and only heavier elements condense here

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

Describe the characteristics of terrestrial planets

A

small core, small volume and high density

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

Describe the composition of jovian planets

A

planetesimals formed from collisions of ice, core becomes massive enough to exert a strong enough gravitational pull to trap H and He to form a large gas atmosphere

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

Describe the characteristics of jovian planets

A

much larger than terrestrial planets since more ice available then metals/silicates, large volume, low density gaseous outer atmosphere and high density icy core

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

Describe the characteristics of Mercury

A

small radius, low mass, cratered surface due to meteorites and long folds in the surface thought to be wrinkles in the crust formed as it cooled and shrank, suggests Mercury hasn’t been active for a long time

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

What are the effects of Mercury low gravitational field strength?

A

1) low escape velocity so no atmosphere, heat escapes quickly
2) no moons

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

Describe the characteristics of Venus

A

similar size and mass to Earth, extremely hot surface temperature, high winds, high pressure, few craters on surface and many volcanoes

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

Why does Venus have such a high surface temperature?

A

extreme greenhouse effect - the high temperature due to being close to the sun meant gases in the atmosphere couldn’t condense to form oceans

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

Describe the composition of the Earth

A

core (inner and outer) made up of iron and nickel, thick mantle made of silicates and the thin crust

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

What are the 3 factors which protect life on Earth?

A

1) liquid water ocean
2) ozone layer

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

What are the 4 main stages of evolution of the Earth?

A

1) differentiation of layers
2) bombardment of the crust by meteorites
3) flooding of lava, then liquid oceans
4) surface evolution due to air, water and plate tectonics

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

What is unusual about the Moon and how is it thought to have formed?

A

it is Earth’s only natural satellite and has a large diameter (1/4 De) compared to moons of other planets
formed due to a collision on the young Earth

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

Describe the characteristics of Mars

A

reddish appearance due to iron oxide dust, thin atmosphere since small gravitational strength

21
Q

What is apparent retrograde motion?

A

when the motion of a planet appears to reverse due to Earth’s orbit being inside that of the other planet and since Earth travels faster it ‘overtakes’ - happens every 2 years with Mars

22
Q

What evidence is there for water and life on Mars?

A

water - hematite has been discovered on the surface and there is still water stored under the ice
life - studies of a meteorite from Mars shows fossilised carbonate globules

23
Q

Why are Mars’ 2 moons irregularly shaped?

A

thought to be asteroids captured by the gravitational pull of Mars
due to small mass don’t have a large enough gravitational strength to squeeze them into spheres

24
Q

Describe the composition of Jupiter

A

composed of mainly hydrogen and helium
intense magnetic field thought to arise from electrical currents in the rapidly spinning metallic hydrogen interior

25
Q

Describe Jupiter’s rotation

A

differential rotation - rotates faster at equator than poles
rapid rotation has caused the planet to oblate (flattened perpendicular to spin)

26
Q

What are the zones and belts on Jupiters?

A

zones - rising currents of gas
belts - falling currents of gas

27
Q

Explain why Jupiter is hotter than it should be according to the laws of black body radiation

A

due to gravitational contraction under its own gravitational forces
atoms are accelerated to higher speeds resulting in increased temperature

28
Q

Describe Jupiter’s moon Io

A

similar composition to terrestrial planets
cracked and distorted surface due to strong tidal forces produced by the planet’s gravitational pull causes volcanic

29
Q

Describe Jupiter’s moon Europa

A

solid surface made of ice rather than silicates
tidal forces produced by Jupiter crack the surface and allow liquid to escape, this freezes and forms ice ridges

30
Q

Describe the characteristics of Saturn

A

low density and shows differential rotation like Jupiter

31
Q

Describe the composition of Saturn

A

made mostly of H and He with a dense core of metals like iron and nickle

32
Q

What are Saturn’s rings made of and how are thought to have formed?

A

small chunks of rock and ice
remnants of a an old moon, fragments are then stretched out to form rings due to Kepler’s laws

33
Q

Describe Saturn’s moon Titan

A

thick atmosphere with a similar pressure to Earth and similar physical features to Earth but methane instead of water

34
Q

Describe Saturn’s moon Enceladus

A

extremely cold due to high reflectivity
close vicinity to Saturn means tidal forces crack the surface and water is forced through the cracks

35
Q

Describe the composition and characteristics of Uranus

A

made of H, He and methane
ring structure similar to Saturn
blue-green appearance due to methane

36
Q

What makes Uranus different to all the other planets?

A

spins parallel to its orbit plane
thought to be a result of a collision with a large object on the early solar system

37
Q

Describe the composition and characteristics of Neptune

A

similar composition to Uranus
faint ring structure

38
Q

What is unusual about Neptune’s largest moon Triton?

A

rotates about Neptune in the opposite direction to the planet’s rotation
thought to be a Pluto like object captured from the Kuiper Belt

39
Q

Describe the composition and characteristics of Pluto

A

rocky and icy composition, more like a comet rather than a jovian planet
smooth surface suggests volcanic activity
demoted to a dwarf planet since hundreds of other similar bodies were discovered in the Kuiper Belt

40
Q

How did the sun form?

A

centre of the interstellar cloud (mainly H) collapses and heats up until it becomes hot enough for nuclear fusion
outward thermal pressure balances inward gravitational forces

41
Q

What is plasma?

A

a ‘soup’ of charged particles which conducts electricity since the nuclei and electrons are free to move

42
Q

What are sunspots and how do they form?

A

dark areas on the surface of the sun due to reduced temperature
differential rotation causes plasma to become twisted and so too the magnetic field, when the field is tightly wound plasma loops form

43
Q

What are coronal loops or prominances?

A

large loops of plasma looping in and out of the surface of the Sun

44
Q

What are coronal mass ejections?

A

violent events which eject large amounts of material (plasma) into the outer solar atmosphere and beyond

45
Q

What are the negative effects of a CME that erupts in the direction of the Earth?

A

damage to satellites, danger to astronauts and causes electrical interference / blackouts over large areas on Earth

46
Q

What natural phenomenon is produced by solar wind?

A

aurora, the charged particles in the wind pass through the atmosphere and collide with O and N molecules, releasing light energy

47
Q

What are exoplanets?

A

planets outwith our solar system orbiting other stars

48
Q

What is the radial velocity method of detecting exoplanets?

A

monitoring the oscillating wavelength of light emitted by a star due to the Dopler Effect
useful for finding large planets with short orbital periods

49
Q

What is the planetary transits method of detecting exoplanets?

A

observing the oscillating brightness of the light emitted by a star as a planet orbits around it
also allows the study of the planet’s atmosphere using spectroscopy

Astronomy (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions