cosmos exam 2

what processes shape (solid) planetary surfaces?

- impact cratering - tectonics - volcanism - erosion

impact cratering

- impacts by asteroids and comets - creating an explosion on the surface - most cratering happened within 1st billion years after solar system formed - craters are about 10 times wider than object that made them - small craters greatly outnumber large ones - there are not many craters on earth because there are processes on earth erasing craters - the dominant process of many terrestrial bodies - surfaces have been touched since impacted

hexagonal cloud pattern around the North Pole of saturn

Could form from turbulence between two cloud bands of very different speeds

Frequency

how fast successive crests pass by a given point - denoted by the Greek letter "nu" Measured in Hertz (Hz)=1 cycle/sec Frequency and wavelength : λx v =c is the speed of light.

Southern Hemisphere of mars

high evelations

Cratering on Venus

Amount of cratering is fairly uniform over the surface Entire surface approx. same age Venus has far fewer impact craters than the Moon or Mercury. Age of the surface is very young The entire surface is ~500 million years old

Interior of Venus

Because Venus is similar in size to the Earth and has active volcanic features, it should have a similar internal structure with a partially molten interior and a liquid outer core But odd that Venus has no magnetic field Outer core is solid, and if so, why? - or - Or slow rotation (243 Earth days) is too slow for charges to circulate in a liquid core. Unclear how thisworks (or doesn't)

Crustal Shrinkage on Mercury

Long cliffs indicate that Mercury shrank early in its history. Cooling core shrank about 20 km Occurred 1-2 Billion years after formation - but geologically "dead" today

impact hypothesis

Pros: Collisions happen (but this is a whopper: Mars sized or bigger!) Explains lack of volatiles in Moon - baked out Explains lack of an Iron core - portion merged with Earth's (merge might explain some composition similarities too) Density is similar to the Earth's crust & mantle Bonus: explains tip of the Earth's axis and rotation rate! Cons: Not easy to eject material far enough away to coalesce into an object with out falling back to Earth Predicts reformed moon orbiting above Earth's equator (again, it's not) Why only one moon?

Fission hypothesis

Pros: Density of Moon similar to that of the outer layers of the Earth Cons: Difficult to explain size of the Moon Earth would have to have been spinning extremely fast Moon should be orbiting above Earth's equator; it's not. Volatile problem still exists

Capture hypothesis

Pros: Possible - Jovian planets have done so Explains why moon is large compared to Earth (because it grew without being interrupted Cons: Difficult to slow moon to capture w/o impact (on the earth) Predicts orbit should be in the ecliptic (it's tilted by 5 degrees) and much more elliptical Compositions should be similar to large asteroids (density ~2100 kg/m3) and contain volatiles (trapped gases) - but moon rocks are missing these volatiles (baked out)

binary accretion hypothesis

Pros: Lots of material in early Solar System to accrete (how Jovian planets formed moons) Cons: Predicts Earth and Moon with same densities (Moon is actually iron deficient) and composition (volatiles should be missing) Moon would be orbiting above Earth's equator (it's not).

Wavelength

The colors are determined by the wavelength of light - Denoted by the Greek letter "lambda" . Visible light measured in: Micron (μm) - 10-6m Nanometer (nm) - 10-9m Angstrom (Å) - 10-10m

mercury basics

(5.5% of earth's mass, 38% of Earth's radius, almost as dense as earth) flybys, radar, orbiter

volcanism (unrelated to plate tectonics)

- "hot spot" volcanism happens when molten rock (magma) finds a path through the crust to the surface - molten rock is called lava after it reaches the surface hot spot volcanism examples: - hawaii - Io

size of craters (earth)

- 10 mile meteor--> 200 mile meteor - 10 feet--> 620 foot crater

continental motion

- 1912: Original idea of continental drift was inspired by the puzzle-like fit of the continents. - In 1950s: Mantle material erupts where the seafloor spreads - Rate = ~2 cm/yr

Rotation and Shape of Jovian Planets

- All rotate much faster than terrestrial planets - Jovian planets are not quite spherical because of their rapid rotation - wider at equator

Difference between Uranus and Neptune to Jupiter and Saturn

- Blue color caused by methane clouds (CH4) - Relatively featureless (one cloud layer) but still have windy turbulent atmospheres - Much weaker magnetic fields - 75% and 50% or Earth's - clue about the interior

Why does the farside lack the Maria of the nearside?

- Crust on farside is 30 miles thicker, magma didn't seep

What are the major geological features of Mars?

- Differences in cratering across surface - Giant shield volcanoes - Evidence of tectonic activity

Earth's surface shaped by plate tectonics

- Divergent Ridges: where crust spreads indicating plate tectonics - can occur either on sea floors or continents - Motion of the continents can be measured with GPS - few cm/yr.

What geological processes shaped our Moon?

- Early cratering is still present. - Maria resulted from volcanism.

medium to large moons

- Enough self-gravity to be spherical - Have substantial amounts of ice -Formation similar to the planets formation around the Sun - Formed in orbit around Jovian planets - Large moons closer to the planet have less ice than more distant ones - Orbit in equatorial plane - Mostly circular orbits in same direction as planet rotation

highlands

- Heavily cratered - Composed of jumbled mountains that were pushed up by craters - Low density anorthosite - ^ what makes it lighter - Light colored

density of matter

- How tightly packed matter is. The amount of mass in a given space - can indicate the proportions of rock, metals etc in a planet

tidal heating and orbital resonances

- Io, Europa & Ganymede are being tugged by Jupiter and each other - Every 7 days, these three moons line up. - The tugs add up over time, making all three orbits elliptical. - 4th moon, Callisto, is too far to be affected much by Jupiter & other 3

ring formation

- Jovian planets all have rings because they possess many small moons close in. - Impacts on these moons or collisions with each other are random. - Saturn's extensive ring system may be an "accident" of our time. neither are permanent structures

Lowlands (aka Maria)

- Less cratered - Composed of low lying, smooth lava flows -Higher-density basalt -Dark colored - Maria: seas in latin - also these were brought back from apollo - both rocks were igneous rocks (molten at one time)

clues the interior of jupiter

- Magnetic field is 14 times stronger than the Earth's at it's "surface" - Density constrains the rocky/metallic core to 1-10 Earth masses - Oblateness implies a largely liquid interior - Mathematical models give us an idea of how this all fits together equatorial radius is 6% larger than the polar radius

earth's density

- Many of Earth's features are determined by its size, rotation, and distance from Sun. - The reason for plate tectonics is not yet clear.

core

- highest density layer 95% iron, rest mainly nickel - outer core is liquid, inner core is solid - metal

Comparing Jovian Interiors

- Models suggest cores of Jovian planets have similar composition. - Saturn has similar internal structure but lower mass and lower internal pressure means layers are in different proportions - Even smaller masses for Uranus and Neptune mean no metallic hydrogen due to even lower pressures inside - Weak magnetic fields as a result - caused by dissolved ions in liquid water near the surface

jupiter and saturn composition

- Mostly H and He gas - Some rock in the core

uranus and neptune composition

- Mostly hydrogen compounds: water (H2O), methane (CH4), ammonia (NH3) - Some H, He, and some rock in the core

Volcanism on Mars

- Olympus Mons - shield volcano - largest volcano in solar system

Then why don't all the Jovian planets have rings like Saturn's?

- Rings will eventually spiral into the planet after 10-100 million years (thus Saturn's rings are recent) - Saturn has too much material to have survived since planet formation and the particles are too small to have survived for so long. - Mass of the rings is half of the moon Mimas (based on Cassini's published March 2019) (medium sized ring) - Ice particle would appear darker if very old (billions rather than millions of years) (because would collect dust) - Must be a continuous replacement of tiny particles or the rings are "recent" formation - if moon gets too close, tidal forces from crossing boundary break up moon and tear it apart so break into chunks forming rings

seafloor spreading/recycling

- Seafloor crust: thinner (5-10 km) & denser than continental crust (20-70 km). - Seafloor quite young compared to continents - fewer sea floor craters - Seafloor crust is created at divergent ridges and recycled through subduction - replaced after 200 Million years; Continental crust isn't recycled

Why do the jovian planets have rings?

- Short answer: Jovian planets have many more moons - Rings formed by random impacts on the icy moons or icy moons colliding with each other - Ring particles are probably debris from moons.

geological processes on jovian moons

- Similar to those on terrestrial planets - Impact cratering - Volcanism - Erosion from Wind & Ice -So far no evidence of: Tectonics, (liquid) Water Erosion - Some processes in operation on Jovian moons but not on terrestrial worlds - Strong tidal forces can heat and melt the interior of the moon - Liquids other than water can occur on moons that are far too cold for liquid water

What geological evidence tells us that water once flowed on Mars?

- Some surface features look like dry riverbeds. -Some craters appear to be eroded. -Rovers have found rocks that appear to have formed in water. -Gullies in crater walls may indicate recent water flows.

methane on Uranus and neptune

- cold methane gas absorbs red light but transmits blue light - blue light reflects off methane clouds, making those planets look blue

What are Saturn's rings like?

- They are made up of countless individual ice particles. - They are extremely thin with many gaps.

magnetic fields

- a planet can have a magnetic field if charged particles are moving inside - requirements: - molten, electrically conducting interior (i.e. liquid metal) - moderately rapid rotation

saturn is different from jupiter bc

- about 1/3 as massive - magnetic field is 20 times weaker - belt-zone circulation but not as well defined - Saturn is colder and cloud layers form deeper, below haze layer

erosion

- blanket term for weather-driven processes that break down or transport rock - processes that cause erosion include: - glaciers - rivers - wind

mantle

- high density rocks - below the crust to 2900 km - medium density

craters give us a sequence of events

- crater on top is younger than the one on the bottom - visible ejecta rays count as part of the crater - but a crater with rays is not necessarily the younger one - if they don't overlap, we're out of luck - sequence: bottom crater, lava infilling, then top -can assume the lava infilling occurred at the same time overlap rule applies to other features - sequence: top left, lava infilling, then lower right

structure of jupiter's atmosphere

- different types of hydrogen compounds form clouds in jupiter's atmosphere - Each compound produces clouds of different colors. - The compounds condense at different temperatures forming cloud layers at different depths

erosion

- dunes-atmosphere - stream beds-flowing liquid

how does the energy from earthquakes travel through the earth?

- energy is transferred by seismic waves - waves of energy travel which through earth

erosion by water

- eroding rock - the Colorado river continues to carve grand canyon

meteorites

- extraterrestrial materials that fall to earth - leftovers from solar system formation - give an indication of what elements formed the earth

igneous rock

- forms when molten rock (lava) cools - implies the planet had hot, partially molten interior when the rock formed

sedimentary rock

- forms when rocks are broken apart and the pieces are "glued" back together again - implies the presence of a liquid (water) on the planet when the rock formed

metamorphic rock

- forms when rocks are changed due to high hear and pressure - implies that plate tectonics were active on the planet when the rocks were formed

erosion by ice

- glaciers carved the Yosemite valley

"age" of planetary surface

- last time it was significantly changed (not necessarily when the surface formed) - by volcanism, wind and/or water activity, plate tectonics, etc - basically anything that erases surface features and forms new rock

lava flows can give us a sequence of events

- lava flowed early in moon's history while interior was still molten - impacts fractured surface allowing lava flows - after moon cooled, craters no longer filled with lava

crust

- lowest density rocks-granite, basalt, etc. - 0-60 km thick (30 km on average)

sources of magnetic fields

- motions of charged particles are what magnetic fields - ex: electromagnets

impact craters

- old feature: significant in distant past, random events today - can be destroyed by other geological processes

role of planetary rotation

- planets with slower rotation have less weather, less erosion, and a weak magnetic field - planets with faster rotation have more weather, more erosion, and a stronger magnetic field - sources of magnetic fields: a planet can have a magnetic field if charged particles are moving inside. requirements: - molten, electrically conducting interior - moderately rapid rotation

seismometers

- records ground motion over time - the record of waves is a seismogram

volcanoes

- requires internal heat-molten interior - interior of planet is hot

lithosphere

- rigid layer that "floats" on warmer rock - crust + mantle

role of planetary size

- smaller world cool off faster and harden earlier -larger worlds remain warm inside, promoting volcanism and/or tectonics - larger worlds also have more erosion because their gravity retains an atmosphere

role of size in cooling

- smaller worlds cool off faster and harden earlier - the moon and mercury are now geologically "dead (as far as motion of rock on surfaces)" - no internal heat - (also no atmospheres- more later)

differentiation

- stratification - causes the planets to go from being homogenous and well mixed to being layered by density - while planet is mostly molten, material separates by density: - gravity pulls by high-density material to center - lower-density material rises to surface

earthquake

- sudden release of energy and subsequent shaking of the ground

if you know the cratering rate, you can get the numerical age

- suppose craters formed on both these areas at a rate of 1 crater per million years. how old are these areas? - left side: 9 million years - right side: 3 million years

ridges of various kinds

- tectonics - requires internal heat-molten interior

a possible history of mars

- the Noachian period - Formation- 3.5 billion years ago -Thicker, warmer atmosphere - rivers, lakes, oceans -Hotter interior - abundant volcanic activity, magnetic field - Southern hemisphere dates from this period the hesperian period - 3.5 - 1.8 billion years ago - Interior cools -volcanic activity slowly decreases -less outgassing -magnetic field dies -atmosphere thins from loss to space -surface cools -Northern plains date from this period and the next period the amazonian period - 1.8 billion years ago to present -Thin, cold atmosphere -Cooled interior - no volcanic activity, no magnetic field -Dominated by wind erosion and meteorite impacts

more craters=older

- the surface with fewer craters was modified more recently than the now with more craters (younger)

convection

- transports heat as hot material rises and cool material falls

volcanic outgassing

- volcanism also releases gases from planet's interior into the atmosphere - creates secondary atmospheres

erosion by wind

- wind wears away rock and builds up sand dunes - can erode and deposit material - sand dunes-mars, earth - wind streak- venus - erosion-earth

Callisto: An old surface

-Density: 1800 kg/m3 - Old cratered surface -Dirty Ice - "Recent" impacts exposes cleaner ice - Darker areas may be dust/rock leftover after surface ice sublimates

Mars' Atmosphere

-Estimated to be 10-100 times thicker in the past -Where did it go? -Polar caps - carbon dioxide ice covering water ice - Ice under the surface - Oxygen locked in rust -Lost to space

Saturn's rings

-Made up of numerous icy particles with a trace of rock -Sizes range dust->boulder>small moons -very thin and have dramatic gaps -orbit around Saturn's equator. b bring: inner a ring: outer moons and rings distorting thick structures/shadows b ring: ringlets - rings are very thin-10m - but some parts can be 1-2 km high!

any moon hypothesis must naturally explain

-Moon's orbital tilt (5 degrees tilted from Earth's orbit) and eccentricity (0.055) -The Moon's lower density - lack of a substantial iron core like the Earth does -Rocks from Apollo missions show a lack of trapped gases and water (volatiles) compared with Earth and asteroids - as soon as you release to surface, it would evaporate (solid to gas) -Rocks also show some isotopes having same proportions as Earth - indicating local origin

Interiors of Jovian Planets

-No solid surface. - Layers under high pressure and temperatures. -Cores (~10 Earth masses) made of hydrogen compounds, metals & rock - layers are different for the different planets

role of distance from sun

-Planets close to the Sun are too hot for rain, snow, ice and so have less erosion. -Hot planets have more difficulty retaining an atmosphere. - because hot air rises. thats why no atmospheres on mercury or moon (too close to sun so gas would dispel into space) -Planets far from the Sun are too cold for rain, limiting erosion. -Planets with liquid water have the most erosion.

inside jupiter

-Pressure and temperature are beyond hydrogen's critical point -No clear distinction between gas and liquid states -Atmosphere around you gradually increases in density until you are in a liquid -A quarter of the way down hydrogen turns into liquid metallic hydrogen -Electrons are ably to move freely like in a metal -Rather than molten metal, this provides the source of the magnetic field - the center of Jupiter is 5-6 times hotter than the Sun's surface - but we don't know much about the actual composition or structure - High pressures inside Jupiter cause phase of hydrogen to change with depth. - Hydrogen acts like a metal at great depths because its electrons move freely. - Core is thought to be made of rock, metals, and hydrogen compounds. - Core is about same size as Earth but up to 10 times as massive.

Medium Moons of Uranus

-Varying amounts of geological activity occur. -Moon Miranda has large tectonic features and few craters (episode of tidal heating in past?) - indicates geologic activity in the past

newton's law of gravity: a primer

1. Attractive force between all masses: every mass attracts every other mass. 2. Strength of attraction is directly proportional to the product of their masses. 3. Strength of force decreases with distance more simply: - everything pulls on everything else - The larger the masses, the greater the pull - Objects close together pull more on each other than objects farther apart

Where did the moon come from?

1. Binary Accretion - The moon formed with the Earth from the same could of debris at the same time (ring of debris due to the equatorial plane) 2. Capture - The moon formed elsewhere (asteroid), drifted too close to the Earth and was captured 3. Fission - The moon formed when the Earth broke up because it was spinning too fast (moon came from Pacific Ocean) 4. Giant Impact - The moon formed from material thrown off during a large impact event (basically size of mars crashes into earth, throwing debris into space... Thea forming too close to earth. remnants from crash formed moon)

lunar evolution

1. Formation of highland crust: 4.6-4.1 billion years ago (top has lowest density) 2. Period of heavy bombardment: 4.1-3.8 billion years ago 3. Formation of maria: 3.8-1 billion years ago (early surface is covered with craters. large impact crater weakens crust. heat build-up allows lava to well up to surface. cooled lava is smoother and darker than surroundings)

jupiter

318 times earth's mass, 11.2 times earth's radius, far less dense than earth

uranus

4.6% of Jupiters mass, 35% of jupiter, less dense than jupiter

neptune

5.4% of Jupiter's mass, 4 times earth's radius, more dense than jupiter

saturn

95 times earth's mass, 9.4 times earth's radius, less dense than jupiter

Jupiter's Great Red Spot

A storm 1.4x as wide as earth. although hurricane-like, caused by high pressure systems, rather than low pressure systems on earth

Jovian Magnetospheres

All Jovian planets have substantial magnetospheres, but Jupiter's is the largest by far.

Do jovian planets have magnetospheres like Earth's?

All have substantial magnetospheres. Jupiter's is the largest by far.

medium moons of saturn

Almost all of them show evidence of past volcanism and/or crustal fracturing. all other moons show evidence of geologic actibity on surfaces (other than mimas)

Jupiter's colors

Ammonium sulfide clouds (NH4SH) reflect red/brown. Ammonia, the highest, coldest layer, reflects yellowish-white

Greenhouse gases

CO2, CH4, H20+ others Absorb different wavelengths of light Transparent to visible lightAbsorb and re-emit IR Visible

jovian cloud layers

Cloud layers in other Jovian are similar to Jupiter's but condense at different altitudes. Uranus and Neptune have a single could layer of methane so we don't see the same banded structure, although they have the same zonal wind flows

Energy Carried by Light

Different colors of light have different amounts of energy. e=h x v = hxc/lambda

Tidal stresses crack Europa's surface ice.

Few impact craters - young surface. Melts the ice about 10 km below the surface

Greenhouse gases absorb and re-emit IR but are transparent to Visible light.

H20, CO2, CH4

What geological processes shaped Mercury?

Had cratering and volcanism similar to Moon Tectonic features indicate early shrinkage.

Why are small icy moons more geologically active than small rocky planets?

Ice melts and deforms at lower temperatures, enabling tidal heating to drive activity.

greenhouse effect with greenhouse

Incoming solar energy Incoming solar energy absorbed by the surface and re-emitted at longer wavelengths Outgoing long wavelength energy is trapped by the greenhouse

Are jovian planets all alike?

Jupiter and Saturn are mostly H and He gas. Uranus and Neptune are mostly H compounds.

jupiter's magnetospher

Jupiter's strong magnetic field gives it an enormous magnetosphere.

triton

Largest moon of Neptune. orbit tells us it was captured. Orbits "backwards" compared to other moons - probably captured by Neptune's gravity from KB. Has ice geysers erupting nitrogen (cryovolcanism). all material is extremely cold. impact basins filled with water. similar to pluto but larger (1st KBO we have seen yet.

What are jovian planets like on the inside?

Layered interiors with very high pressure and cores made of rock, metals, and hydrogen compounds. Very high pressure in Jupiter and Saturn can produce metallic hydrogen.

plate motions on earth

Measurements tell us past and future layout of the continents.

Was Earth's geology destined from birth?

Many of Earth's features are determined by its size, distance from Sun, and rotation rate. The reason for plate tectonics is still a mystery.

Volcanoes on Venus

Many volcanoes, including both shield volcanoes and stratovolcanoes. Lava plains also evident Assume still geologically active sulfur dioxide in atmosphere from volcanic outgassing

How is Earth's surface shaped by plate tectonics?

Measurements of plate motions confirm the idea of continental drift. Plate tectonics is responsible for subduction, seafloor spreading, mountains, rifts, and earthquakes.

cratering of mercury

Mercury has a mixture of heavily cratered and smooth regions like the Moon. Most cratered planet Smooth regions are likely ancient lava flows. - caloris basin is largest impact crater on mercury - "hollows"-collapsed crater floor created by escaping gases

Io

Most volcanically active body in the solar system (including Earth!). Driest place in the solar system: tidal heating effectively boiled off all water. Tides cause the surface to rise and fall by 330 feet each orbit (1.8 days). Surface has no impact craters - frequent eruptions. outgassing sends stuff in space

Jupiter's atmosphere

Mostly Hydrogen (86%) and Helium (13%). Cloud layers where ammonia (NH4) ammonium hydrosulfide (NH4SH) and water vapor (H2O) condense. Belt-zone circulation (rotation period - 10h). Long-lived storms - Great Red Spot visible since Galileo observed it over 400 years ago

surface features of earth

Mountains form formed from collision between plates. -The Himalayas The Red Sea is formed where plates are pulling apart.

What is the weather like on jovian planets?

Multiple cloud layers determine colors of jovian planets. All have strong storms and winds.

Erosion on Venus

Photos of rocks taken by landers show very little erosion. Too hot for water Rotation to slow for strong surface winds

geology on rocky planets versus icy moons

Rock melts at higher temperatures. Only large rocky planets have enough heat for activity. Ice melts at lower temperatures. Tidal heating provides continuingenergy, melt internal ice, driving activity. if planet is cooled off, then geological activity is gonna cease

titan

Saturn's largest moon. has a thick, opaque atmosphere rich in nitrogen (98.4%), 1.6% methane and traces of other hydrocarbons (including ethane, acetylene, ethylene, and propane). cold enough that methane condenses and forms lakes: so weathering--> very few impact craters. Radar map shows few impact craters & river beds. Surface mostly water ice and slushy methane. Huygens probe: first look at titan's surface ein 2005. it found liquid methane and rocks made of ice

saturn's colors

Saturn's layers are similar, but deeper in (and more subdued)

Types of moons orbiting the Jovian planets

Since they formed beyond the "frost line," the moons of the outer solar system have a large proportion of ice.

Rifts, Faults, Earthquakes

Sliding motion of plates can cause earthquakes. - Motion between plates isn't smooth, rough edges catch - San Andreas fault in California is a plate boundary.

Surface of Venus

Smooth, rolling lava plains Deformed highlands (tessera) Unlike the Moon and Mercury - no ancient plains

gap moons

Some small moons create gaps within rings (gravity of moon can move moons)

What Effects Tidal Heating

Strength of gravity - causes the tidal force - Gravity depends on both mass of the moon and planet and distance between them -Larger the masses - stronger the force - Closer the distance - stronger the force - Changing shape of orbit stretches the moon - Circular orbits forces are constant and unchanging - no changing of moon shape - More elliptical the orbit - more stresses from increasing/decreasing tidal forces

Spectra for Sun and Earth

Sun gives of mostly visible & IR, some UV; Earth gives of mostly IR & reflects visible

sunlight

Sun radiates mostly visible and IR and a small amount in UV

valles marineris

The system of valleys is thought to originate from crust shift (tectonics?) not erosion like the Grand Canyon

tidal heating

The moon is squished and stretched by gravity as it orbits the planet. Very elliptical orbit changes the tidal forces

.How do other jovian ring systems compare to Saturn's?

The other jovian planets have much fainter ring systems with smaller, darker, less numerous particles.

What is special about Titan and other major moons of the solar system?

Titan is only moon with thick atmosphere. Many other major moons show signs of geological activity.

Possible History of Venus

Venus starts outgassing a thick, carbon dioxide rich (secondary) atmosphere. Most likely had liquid water on surface, too Brightening of the Sun causes Venus to be too warm for liquid water to stay (vaporizes immediately), triggers runaway greenhouse effect Next 4 Billion years ???????????????????????? Periodic, planet-wide overturning of crust? Or did Venus have plate tectonics like the Earth until a recent, single resurfacing event Why no plate tectonics now? How did the tessera form? history beyond 500 million years is gone

Atmosphere Absorption Spectrum

Very little absorption at visible wavelengths Absorption of UV by ozone in upper atmosphere Absorption of IR by greenhouse gases in lower atmosphere

GHE effect

a natural process and the surface of Earth would be much colder w/out GHE

p waves

a type of seismic wave. - push and pull - fastest waves so arrive first - travel through solids and liquids

S waves

a type of seismic wave. - shake side to side or up and down - 2nd fastest, so arrive after p-waves - travel only through solids

Evidence for Liquid Water on Mars

ancient stream valleys and outflow channels plains and river deltas; seepages coming from crater and valley walls; sedimentary rock on the Martian surface - Spirit and Opportunity rovers have found "blueberry" rocks - hematite - that appear to have formed in water. - erosion of craters - Pressure and temperature must have been favorable for large scale water flows in the past - though not today - Details of some craters suggest they were once filled with water.

if you measure the temperature of the Earth from a satellite, far above Earth's atmosphere, you would get a temperature of

approximately 255 K (0 degreeF).

today- moon is geologically dead

because geological processes have virtually stopped. - no igneous rock currently forming

interior of mars

core, mantle, crust

jovian aurorae

coronal mass ejection--> energetic particles stream outward--> are caught in magnetic field--> causing atmospheric gases to glow

plate tectonics

crust is fractured into plates which floor on age warm underlying layer (why they get to move)

ganymede

dark, old terrain and bright, young terrain - Largest moon in the solar system - Clear evidence of geological activity from tidal heating - 3 mile deep ocean lying about 110 miles below surface

tectonics

disruption of a planet's surface by internal stresses - large scale processes affecting the structure of the [earth's] crust - releases heat from a hot, partially molten interior primarily at plate boundaries what happens underneath surface in the mantle - most heated by core (liquid iron)- at bottom, hot rock wants to rise and starts to solidify as it falls back down (convection cells) - convection of the mantle creates stresses in the crust called tectonic forces - compression of crust creates mountain ranges - valley can form where crust is pulled apart

Surface of planet is heated by

energy (light) from the Sun AND from energy (IR light) re-radiated from the atmosphere

erosional debris

erosion can create new features such as deltas by depositing debris

volcanism

eruption of molten rock onto surface

small moons

far more numerous than the medium and large moons not enough gravity to be spherical: "potato shaped" captured asteroids or comets, so their orbits do not follow usual patterns

missions to jupiter, saturn, uranus and neptune

flybys of all and some moons, orbiter and atmospheric probe to Jupiter, orbiter to Saturn, lander to titan (moon)

secondary atmosphere

formed by outgassing during differentiation. example: Venus (co2)

primary atmosphere

gas collected during the formation process. example: jovian atmospheres mostly hydrogen and helium

Greenhouse Effect In a nutshell

incoming solar energy (mostly visible light) Incoming solar energy absorbed by the surface and re-emitted at longer wavelengths (mostly IR) Outgoing long wavelength energy escapes to space

what is necessary for a planet to differentiate into separate layers

it must be a mix of materials of different densities and material inside must be able to flow

infrared

longer wavelengths

northern hemisphere of mars

low elevations

Flat lava plains

made of runny lava. ex: Moon (fills up craters) - lowest temp and density

shield volcanoes

made of slightly thicker lava. ex: mars medium density and temperature

stratovolcanoes

made of thickest lava. made very steep. ex: earth

iapetus

medium moon of saturn. Odd equatorial ridge - dramatic 'two-tone' coloration. plowing through material that makes rings

Enceladus

medium moon. Saturn's icy moon. Tidal heating. Ice fountains suggest it may have a subsurface ocean.

crater dating

moon and mercury is dominated by craters (tells us how old that surface is)

pan

moon of saturn. space empanada. orbits within the rings, pulls material off them

moon

only celestial body that has had manned missions. also flybys, crash landers, soft landers, orbiters, and impactors. ~1% of earth's mass, 27% of earth's radius, way less dense than earth

body waves

p-waves and s-waves travel through earth

transform

plates moving past each other (without colliding or splitting) features associated: - earthquakes

divergent

plates moving past each other (without colliding or splitting) features associated: - mid-ocean ridges (all caused by plates separating) - underwater volcanism - earthquakes

convergent

plates moving toward each other or colliding features associated: - mountains - when two plates coverge into each other - in oceans, land plate rides over oceanic crust (subducting oceanuc lithosphere) - volcanism - caused by plates subducting lithospheres - deep sea tranches - earthquakes

Greenhouse gases in Earth's atmosphere keep infrared radiation from

rapidly escaping into space

jupiter's bands

red cloud layers are brighter in the infrared-warmer

ring systems on other Jovian planets

rings were discovered because would eclipse background stars. all four Jovian planets have ring systems. others have smaller, darker ring particles than saturn

xenoliths

rocks from earth's interior. deepest come from ~300 km (186 miles)

tertiary atmosphere

secondary atmosphere that has been significantly modified. example: earth

shadow zones

seismic waves tell us what's inside earth - p waves go through earth's core, but S waves do not - we conclude that earth's core must have a liquid outer layer - size of shadow zone determines core size

radiation

sends energy into space

UV

shorter wavelength

'shepherd' moons

small moons can force particles into a narrow ring

surface of mars

smooth, young plains in north... and cratered highlands (here, values mariners and shield volcanoes)

view of ring gaps

solid pieces, numerous rings instead of divisions we see

erosion

surface changes by wind, water, or ice

hot spots

the Hawaiian islands are formed where a plate is moving over a volcanic hot spot- a plume from the mantle

The amount of energy absorbed by Earth from the Sun is equal to

the amount of energy given off by Earth.

All objects (solid, liquid, gas) absorb and emit EM radiation, but

they do so at different wavelengths

Europa's interior warmed by

tidal heating

conduction

transfers heat from hot material to cool material

surface wave

type of seismic wave

europa

very young, bright surface cracks-up to 1800 miles long - No dark, dirty terrain - entire surface is young - 100 mile deep ocean lying about 10 miles below surface - Bluish-white areas - relatively uncontaminated water ice - Brown areas on right - dried salts - Yellowish area? Cracks - up to 1800 miles long

plates interact

with each other at their boundaries (these boundaries have traits that we can see in topography) - divergent - convergent - transform

mars

~11% of Earth's mass, ~53% of Earth's radius, less dense than earth. composed of mostly carbon dioxide, less pressure than earth, dry water, temp: ~-80 degrees Fahrenheit

venus

~82% of Earth's mass, ~95% of Earth's radius, less dense than earth. Mostly carbon dioxide. 90 atm at surface. Average ~870°F.

Light

• Light is radiant energy. • Speed - c = 300,000 km/sec • Has characteristics of both a wave and a particle

Sizes of Moons

• Small moons (< 300 km) — No geological activity • Medium-sized moons (300-1500 km) — Geological activity in past • Large moons (> 1500 km) — Ongoing geological activity