Unit 3 Flashcards
1
Q
What characteristic is used to differentiate gas planets from terrestrial planets?
A
Based on its density
2
Q
What elements are common in rocky planets?
A
Silicon, Oxygen, Aluminum, Mg, Sulfur, and Iron
3
Q
What is the most abundant rock type?
A
BASALT
4
Q
Do planets close to the Sun experience more or less bombardments?
A
The closer they are the more often it will be bombarded, because of its massive gravitational pull
5
Q
Which model is favoured for how the Moon originated?
A
The giant impact hypothesis, Earth’s spin and the Moon’s orbit have similar orientations etc.
6
Q
Why was the Fission hypothesis rejected?
A
Would have required that Earth rotated once every 2.5 hours rather than once every 24 hours
7
Q
Why was the Condensation hypothesis rejected?
A
They didn’t have the same chemical composition AND the Moon doesn’t orbit Earth exactly on an equatorial plane
8
Q
Why was the Capture hypothesis rejected?
A
Probability for the exact gravitational and dynamic conditions needed for an object the size of the Moon to fall into orbit about Earth is unlikely. Chemical were so similar between the 2 that there had to be some genetic relationship. Lastly all computer model attempts failed
9
Q
What is the Giant Impact Hypothesis?
A
A planet that was somewhat smaller then Earth, gave Earth a glancing blow sometime about 4.5 billion years ago
10
Q
What is Theia?
A
A hypothetical planet smaller than Earth
11
Q
How did the Giant Impact affect Earth’s structure?
A
Glancing blows gave an increased angular momentum, metal core dropped into earth giving it a large metal core and high density
12
Q
What materials make up the Moon and why is it similar to Earth?
A
Molten mantle material, which formed debris, which was collected and formed into the moon, similar to Earth because some of the debris fell back on to earth
13
Q
What evidence is used to support that the Moon formed as a result of a large impact?
A
Using the computer simulation, shows near complete mixing of Theia with Earth, and ends with a disc of material from which the Moon could form
14
Q
Was the impactor (Theia) large or small?
A
It was roughly the size of Earth (fairly large)
15
Q
What some facts about Earth? (size, density, internal zone)
A
Its the 5th largest planet, Densest body in the Solar System
16
Q
What are the properties of the Hydrosphere and Atmosphere?
A
Our hydrosphere has water on the surface, a largely closed system:you neither lose nor gain water. Our atmosphere is mostly nitrogen and oxygen
17
Q
What makes Earth unique among the terrestrial planets?
A
Its magnetic field is uniquely strong. Mercury and Mars is weak and Venus has none
18
Q
Explain the role of Accretion in the formation of the Earth
A
Earth grew by the accretion of smaller objects, objects would have attracted others by simple gravity and eventually became an actual planet
19
Q
How was Earth’s core formed?
A
With accretion??
20
Q
What is the most common element on Earth?
A
IRON
21
Q
What is the largest zone of the Earth?
A
The Mantle
22
Q
How do pressure, temperature and density change as you move from the crust towards
the core?
A
All 3 will increase
23
Q
Why does Earth have a magnetic field?
A
Because it has an internal ‘generator’ of electric currents
24
Q
What is the evidence that supported the hypothesis of continental drift?
A
Observed that part of the coastline of Chile had been raised up as a result of a great earthquake. Fossils and shells were found in odd spots etc
25
Give an example of how you can tell the order in which rocks were formed based on their relative position
When observing a sequence of undisturbed horizontal sedimentary rocks that the layers at the bottom of the sequence are older than those at the top
26
How can we use radioactive elements to determine the age of a rock ?
Uranium and Thorium are used because it takes millions-billions of years for the parent to decay
27
How old it the Earth, its surface and the ocean floors?
Around 4.5 billion years old, and the surface a slightly younger and the ocean floors are hardly ever over 250 million years old
28
Describe how the Earth’s atmosphere, hydrosphere and biosphere are interconnected
Water vapour in the atmosphere started to condense and rain began. When it started raining, the hydrosphere was born. Biosphere appeared because the ocean was sheltered from the hostile atmosphere
29
How does Earth's atmosphere differ from Mars and Venus?
Earth's is dominated by mostly nitrogen while Mars and Venus contain very little amounts of nitrogen
30
Where did Earth's water come from?
From comets and asteroids that pummelled into Earth
31
Explain two ways that biology has affected the composition of the atmosphere – how are
these changes beneficial to life?
Through photosynthesis, adding oxygen into the atmosphere AND through the removal of carbon form the atmosphere
32
How did Prokaryotes avoid toxic effects of the
| oxygen they produced during photosynthesis?
Iron has a strong ability to absorb oxygen, so the oxygen would have quickly combined with iron, oxidized iron is insoluble in water, oxygen formed would never leave the ocean
33
How do we finally start to accumulate oxygen in the atmosphere and what were the effects on
biology/evolution?
Eukaryotes, used oxygen for respiration, and contributed great amounts of oxygen to the atmosphere
34
How is CO2 removed from the atmosphere and how does this affect Earth’s temperature?
It was combined with Calcium, as they were removed, the temperature declined
35
Trojan Satellite
An object that has the same orbit as another body, but doesn’t collide with that body because it’s located in a particular point on the orbit called Legrangian point
36
Has Earth ever had more than 1 satellite?
Yes, the moon sometimes had a partner
37
How do we know the Moon doesn't have an atmosphere?
If the planet has an atmosphere, smaller meteoroids may be destroyed in that atmosphere or slowed so much they do not make craters, but we see craters of all sizes on the Moon
38
How do we know the Moon doesn't have any plate tectonics?
Plate tectonics requires that the body remain hot long enough for the interior to convect and keep the crust moving. The moon, being relatively small, was not endowed with much heat to begin with, and it cooled relatively quickly
39
What does the study of impact craters tell us about the age of the Moon?
These craters accumulate with time. The older a surface, the more impacts it has experienced
40
What is the Maria and why does it only occur on the near-side?
Dark area, filled with solidified basalt lava an IDK why
41
Are you more likely to see small craters form the Moon or Earth?
On the Moon
42
If the same size meteorite hit Earth and Moon, which would have a bigger crater?
The Moon
43
What are the steps for a crater formation?
Kinetic energy of high speed impacts is converted upon impact into thermal, acoustic and mechanical energy; latter fractures, distorts and ejects rock from the impact site
44
What is Crater Saturation?
A point of saturation when every new crater obliterates an old one
45
Why are all Moon rocks Igneous?
Because they formed by the cooling and solidification of molten rock
46
Why aren't sedimentary rocks found on the Moon?
Because the Moon, never had water on its surface
47
How is regolith formed?
1% is meteorite fragments, the rest is composed of the smashed remains of Moon rocks that have been ground down by the constant blasting by meteoroids
48
Is there Seismic Activity on the Moon?
Yes, but much less than the Earth
49
What is the Geological History of the Moon?
Dominated by the fact that the Moon is small, only a quarter of Earth.
50
Why is it hard to see Mercury?
Because it stays in the same region of the sky as the Sun
51
How is Mercury similar to the Moon? but there surfaces differ?
The both have a rotation altered by tidal attraction, heavily crater, and are small, airless and have inactive surfaces, though mercury has large cliffs
52
What mission provided the most info on Mercury?
MESSENGER
53
Which is longer, a day or a year in Mercury?
A day is longer
54
Is Mercury's surface hot or cold?
Depends where its facing, can ranging from 427 degrees to -173
55
What is the origin or Mercury's atmosphere?
Consists of atoms blasted off its surface by the solar wind, which escapes into space
56
What is the evidence for lava flows on Mercury?
Caloris Basin in partially filled with lava flows,
57
What does Mercury have a low Albedo?
Its the proportion of light that get reflected by a planetary body, which is why its appearing so dark
58
Why do we see faults and scarps if theres no plate tectonics?
Large fault scarps were likely caused by shrinkage, estimated that as Mercury cooled, its diameter has decreased by at least 10 km
59
How are 'hollows' formed on Mercury?
'pits in the surface' thought to be formed when material beneath the surface was vaporized away after asteroid impacts
60
How does the interior of Mercury compare to Earths?
Denser than all planets except earth
61
What is the geological history of Mercury?
Formed in the innermost part of the solar nebula, suffered heavy cratering, flooding began w/ lava flows, and micrometeorites grinded the surface to dust
62
What 2 elements are common on the surface of Mercury?
Sulphur and Magnesium
63
How do we whether there is water on Mercury or not and why hasn't the sun evaporated it?
YEs there is water-ice at least 10-30cm thick, hasn't evaporated because its never exposed to sunlight
64
Why is it hard to see Venus?
It can only be seen 3 hours before sunset or after sunrise
65
What are our 3 main sources of info about Venus?
USSR missions and Magellan and the Venus Express
66
Why does Venus rotate clockwise?
Likely all planets rotated in the same sense originally, and got knocked about by large impacts toward the end of their growth period
67
Which is longer, a day or a year in Venus?
A day
68
What is the composition of the cloud layer?
Droplets of liquid/solid sulphur and droplets of sulphuric acid
69
What is the main component of Venus' atmosphere?
Carbon dioxide
70
How is Venus' greenhouse effect different from Earth's?
Venus' is fearsome, Begin with incoming short wavelength light energy from the Sun warming a planet’s surface but ends up with a surface or near-surface growth of heat
71
Of Mercury, Venus and Earth which is the hottest?
Venus
72
Was there ever water on Venus, if so what happened?
Yes, but without an ozone layer to protect it from ultraviolet radiation, the water was broken up and lots of hydrogen was lost to space. Venus express detected OH in its atmosphere
73
Earth and Venus have similar amounts of carbon, so why doesn’t Earth have the same
runaway greenhouse effect as Venus?
if all CO2 in Earth’s rocks were put back into the atmosphere, our air would be as dense as Venus’ and we would suffer from a severe greenhouse effect
74
Why are their fewer impact craters (and fewer small craters) on Venus compared to
Moon and Mercury?
Small objects just burn up through friction w/ the atmosphere
75
What is the evidence that the surface of Venus is young?
Crater analysis says the surface is about 500M years old
76
What volcanic features exist on the surface of Venus?
Coronae, Caldera, and Pancake volcanoes
77
What causes a global volcanic event? Evidence?
Radioactive heat keeps the inside hot, lacks of plate tectonics could build up a lot of heat and boil over into a volcanic eruption
78
Why do rocks erode faster on Earth than on Venus?
On Earth, such sharply sculpted surfaces would have begun to crumble almost as soon as they formed. Rocks may be much stronger on Venus simply because they have zero water content.
79
What causes erosion on Venus?
Wind
80
What causes the weak magnetic field on Venus?
Interaction between the solar wind and atom/molecules of the upper atmosphere makes a weak magnetosphere
81
What is the proposed geological history of Venus – how does this compare to the stages of formation of the other rocky planets you have read about so far?
1.Differentiaion 2.Catering 3.Flooding 4.Slow Surface Evolution. Main difference between Earth and Venus is the lack of water on Venus
82
What are the arguments for and against Venus having a partially liquid core?
If Venus does indeed have solid-liquid cores but no difference in rotation speed of the two, there should not be a magnetic field. Of course, the planet is just barely rotating at all, so maybe that’s the explanation.
83
Why is there no active plate tectonics on Venus?
The crust is so hot that it is halfway to the melting point of rock, which is not very stiff, so it can’t form the rigid plates typical of plate tectonics
84
Do canals exist on the surface of Mars?
Yes and no? someone misread canali as canals and canals of mars was born
85
Is Mars smaller or larger than Earth?
SMALLER
86
Are there polar caps or a greenhouse effect on Mars?
There are polar caps and a greenhouse effect
87
Is there evidence for life on Mars?
No evidence
88
Does Mars have satellites and are the round?
It has 2 phobos and deimos, and yes they are?
89
Does Mars have seasons?
Yes cause its at a 25 degree tilt
90
Which is longer, a day or a year in Mars?
A year
91
What are the spacecrafts that explored Mars' from its surface?
Curiosity and Opportunity
92
What are Curiosity’s objectives and what kind of evidence might it look for?
Investigate whether Mars could/has ever held microbial life, Explore the presence of water on Mars, Explore martian climate, Explore martian geology.
93
Does Mars have an atmosphere? (primary composition, water?, how it affects the soil)
Yes it has an atmosphere with clouds and ice deposits at its poles, called “polar caps” like Earth. A chemical analysis of an igneous rock, and soil analysis that showed an unexpectedly large concentration of water from hydrated material and the presence of organic molecules
94
How did the atmosphere of Mars form? (similarites/difference from other planets)
Like the other terrestrial planets, would have had a ‘primitive’ atmosphere of hydrogen and a little helium, with a bit of argon, neon etc. But would have to be replaced by a secondary atmosphere of volcanically emitted gases
95
What are the implications of high versus low escape velocity to the atmospheric composition?
The more massive the planet, the stronger its gravitational attraction, higher its escape velocity is, the more difficult it is for gas atoms to leak into space. But Mars' mass is smaller than Earth's so its escape velocity is less than half of Earths
96
How does the size of a planet affect the composition of its atmosphere?
By creating a smaller or larger escape velocity, gas atoms on Mars can escape from it much more easily than they can escape from Earth
97
Can water escape Mars’ atmosphere? How is it lost?
Ultraviolet photons from the Sun can penetrate deep into the atmosphere and break up molecules such as water. While whole molecules of chemicals may be too massive to be lost to space, if they can be broken down, the components can still be lost
98
What evidence do we have for weather, storms or wind on the surface of Mars?
Solar wind interacts directly with both the martian atmosphere and the planet surface????
99
We have not found liquid water on Mars, but what evidence do we have that there is/was water on Mars?
Significant amounts of water are ‘hidden’ in the crust. The existence of hydrated salts in these recurring deposits, salts are perchlorates which lower the melting point of ice and allow water to flow at temperatures as low as -70
100
Compare plate tectonics on Mars, Earth and Venus
Mars' surface has never broken into moving plater like Earth, but its more similar to Venus' a one-plate planets
101
Why does Mars surface lack the regolith seen on the Moon?
The atmosphere of Mars, thin though it is, protects the surface from the blast of micrometeorites that grinds Moon rocks to dust. And martian dust storms may sweep fine dust away from some areas and leave larger rocks exposed.
102
Why are there few craters on the northern lowlands?
It must have been resurfaced roughly a billion years ago. Astronomers have suggested that volcanic floods filled the northern lowlands and buried the craters there
103
Give examples of surface features that tell us something about the crust of Mars
Olympus Mons hasnt sunken into Mars crust meaning its crust is much thicker than Earth
104
What does the mineralogy of Martian soils tell us about the environment
Mars with postulated episodes of a moist climate would be ideal for producing the observed red martian dust. Blueberries are a major ingredient of the soils, they are iron oxide formed into spherules by gentle rolling water.
105
Compare the Martian core to the other terrestrial planets
Mars' core is not solid, its like a thick, 'goopy' syrup.
106
Mars has some of the largest volcanoes in the solar system – in general how are they formed?
???
107
What are the 4 stages of developmental history of Mars?
1.Differentiated into a core, mantle, crust. 2. Cratering 3.Flooding 4. Crust is too thick to be active
