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92 Cards in this Set
- Front
- Back
where can we find meteorties
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arid old pieces of earth, no human competition
Antarctica, or desert |
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where do most metorites come from
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astroid belt
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carbonaceous chondrites
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-4.6 billion years old
-basic building block of solar system - not differentiated |
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ordinary chondrite
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-most of what hits the earth
-cc that have been heated -lack volatiles - parent body big enough to have started heating -only changed a little, somewhat primitive |
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Achondrites
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basalt, impact breccia, pristine Highlands
-from astroids that were big enough to be geologically active |
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stony-iron
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-from transition zone between iron core and rocky outside,
-very rare, pretty |
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Iron
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-easy to find
- don't weather well -widmanstatten - cores of astroids |
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Widmanstatten patttern
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-crystals of iron and nickel, that formed while cooling, cooling must be very very slow
-tells us meteorites are from core of astroids -size of pattern tells how fast/slow it cooled |
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shape and size of astroids
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most are potato shaped
-for every 1 astroid there are 10 1/3 of its size -and astroid 500 km+ is spherical in shape |
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asteroids and geological activity?
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- astroids are dead, no geological activity
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how are astroids composed
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rubble piles, which is why they don't spin as fast as they could
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what is the astroid belt/ how is it formed
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- a planet that never formed b/c of Jupiter
-know it wasn't formed from destruction of larger object because there are some very primitive astroids |
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kirkwood gaps
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occur because of whole number resonances with Jupiter, hey are empty
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resonances
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- astroids are kicked in or out of astroid belt causing meteorites
-3:2 is a non harmful resonance |
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igneous astroids
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belt closer to the sun
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primitive astroids
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belt farther from the sun
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electromagnetic spectrum:
grey white and black |
have straight lines across reflective spectra at different albedo
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electromagnetic spectrum:
colored objects |
have high albedo at the color they are
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remote sensing
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can tell us what a rock is made of by looking at the reflectance spectrum of a rock- different minerals absorb and reflect light differently
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Filters
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used to look at rocks similar in color and differentiate them
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irregular satellites
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-small(astroid size)
-formed by capture -orbit: prograde and retrograde high eccentricity high inclination far from planet |
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regular satellites
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-large (earths moon size)
-formed by co accretion -orbit: prograde low eccentricity (pretty circular) low inclination (around equator) close to planet synchronous rotation(same side toward planet like moon) -composed of ice and rock |
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rings
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-very small (cm to mm)
-orbit: prograde, very close to planet, low eccentricity, very low inclination |
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roche limit equation
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2.5(radius of planet)
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roche limit
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the border between where the gravity is repulsive and where it is attractive
If the two smaller masses are far away from the large mass, the attractive force is dominate. If the two masses are close to the larger mass the repulsive force will dominate. |
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roche limit rings and moons
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So what does all of this have to do with rings? Well, the ring systems of the giant planets all lie within the Roche limits of the planets. The rings are remnants of material of the early solar system that never formed into satellites because they were within the Roche limit. When two object came together, they did not accrete into a larger body, but moved apart and stayed smaller objects. A bit of an oversimplification is: inside Roche limit - Rings, outside Roche limit - satellites.
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in order to have tidal heating you need
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1. A massive central planet (Tidal forces depend on mass)
2. A moon orbiting close to the massive planet (Tidal forces really depend on distance). 3. Another moon in resonance with the inner moon. (You have to force an eccentric orbit in order to keep the distance between the inner moon and the planet changing) |
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short period comets
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100 yrs or less
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where do short period comets originate
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in kuiper belt
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how are short period comets orbits
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mostly prograde
orbit in same plane as planets |
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where do long period comets originate
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oort cloud, very far away
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how are long period comets orbits
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random orbigs
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compostition of comets
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ice and rock
Ices: H2O, CO2, CO, NH3, CH4 |
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tails
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ion tale
dust tale |
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dust tail
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The dust tail consists of dust particles that have been pushed out of the coma by radiation pressure from the sun.
– The dust particles in the tail are individually in orbit about the sun. |
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ion tail
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• The solar wind sweeps past the comet at about 500 km/s, causing the Ion tail to be swept in the anti-solar direction.
• magnetic force is very strong and produces ropes, knots and streamers that distinguish the ion tail from the dust tail. |
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meteor showers
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when a comet hits the earth the particles cause a meteor shower
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saturn rings
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small, .6 albedo, very bright made of ice
-thickness only 100 m -lots of gaps b/c of resonance with outside satelies |
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f ring
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outside r-limit, there b/c it is being herded around by 2 little moons
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Uranus and Neptune rings
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similar to saturn's rings
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Jupiter's rings
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-aren't because of r-limit
- dark -made of dust -made of particles knocked off Jupiter's moons by astroids |
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Calisto
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denisty 1.86 Albedo .3
-no geological activity - dominated by small craters |
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outer soar system craters
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hit by comets, smaller, did not go through late heavy bombardment
can't crater count because we have nothing to calibrate it with |
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titan
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evidence of methane lakes,
maybe be and ice ocean below surface causing it to slip |
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Io
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density 3.53 A=.6
-tidal heating -2:1 resonance with Europa |
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Io volcanoes
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-similar to geysers
-small shield volcanoes, rich in sulfur -when cooling lava flows like water, when hot it flows slower -color orange yellow |
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Europa
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Density 3.02, Albedo .64
-big things punch through surface - inside Jupiter's snow line -global ocean |
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enceladus
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1.6 density A= .99
-orbits Saturn -don't know what is heating it, there is local geological activity, -if tidal heated then mimus must be but mimus is dead |
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Triton
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-orbits Neptune, retrograde, high inclination
-triton was captured, its moon took away excess energy -thin secondary atmosphere which disapears -active volcanism powered by solar heat -used to be part of Kuiper belt |
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kuiper belt
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unformed planet because it didnt have time accretion time =10^8(d/au)^3yrs
-hard to see because all objects are small and dark -at lebrange points of Neptune, kicked around by Neptune |
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pluto
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high eccentricity
small mass small atmosphere (probably volatile elements slowly evaporating) -dwarf planet |
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Oort cloud
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defines edge of solar system
kicked around by Jupiter |
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red spot
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-storm simalr to cyclone, high pressure system, because Jupiters atmosphere is so far above the ground they storm lasts longer because there is no ground for it to interact with
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primary atmosphere color
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colorless, and clear- hydrogen
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secondary atmosphere on Jupiter
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where the color comes from, sulfur
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Jupiter's atmosphere
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smooshed together from gravity
coriolis effect |
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uranus and neptune color
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methane clouds because it is cooler
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Jupiter's core
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metallic hydrogen because of gravity, very magnetic
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3 things to have magnetic field
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-spin fast
- internal heat source -conductor |
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magnetic field and biology
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good protects us from solar wind
-particles can get trapped in radiation belt - particles that ride magnetic field in create aurora |
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magnetic field of uranus and neptune
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made from ionic ocean, so i doesn't coincide with rotation axis's, and these oceans aren't at the core of the planet
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how we know the activities of magnetic fields
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the direction of grains in rocks
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how solar formed
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gas and dust collapse and stars are formed with giant disk of dust around them
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material in solar system comes from
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super nova, previously recycled stars
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how long must planets be made in and why
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10 million years because after that the sun gets violent and blows all gas and dust away
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condensation temp
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the temp they go from a gas to a solid, metals and rocks have higher temps
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why is Jupiter so big
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it was first planet to form outside snow line- the amount of material you have to build a planet decreases as you move away from the sun
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how Jupiter was built
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1st build terrestrial cores
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mass and size of jupiter
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gravity overcomes strength of materials in the core of jupiter so that it is the same size as saturn but much more massive after a certain point nuclear fusion starts, but jupiter isnt massive enough,
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problems with our solar system formed by accretion
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-U and N would take longer than age of solar system to form where they are
- |
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planetary migration
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planetary interactions, cause planets to move
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nice model
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maybe U and N formed closer to the sun then interactions w/ J and S kicked them out, J and S have a 2:1 resonance
-explains late heavy bombardment, scattered oort cloud and left over Kuiper belt -inner solar system planets would have to form in outer solars system and then move in to have water on them |
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future of earth
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as sun gets bigger h20 evaborates and creates a green house effect, becomes venus like
-.5 blyr photo synthesis no longer works 1 blyr eather becomes venus line |
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circumstellar disk
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the disk from which planets are formed
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nebula
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where stars are being formed
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Radial Velocity
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-only cares about light from central star
-measure shift in spectra of star, away or towards instead of measuring the stars actual movement - |
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Doplar effect
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the sift in color of the light of star
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Amplitude
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bigger variation the more massive the planet
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Period
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Distance Planet is from central star
Kepler's 3rd law |
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planets fount by radial velocity
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make up most the planets discovered
most have big planets closer to the sun biased because bigger variations with bigger size and lest time to observe the closer to the sun means planetary migration is probably common |
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transit
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when planets cross in front of central star
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transiting planets
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you can take a spectra of planet itself and get the chemical make up
star+planet-star |
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is there a signature of life in atmosphere
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yes, oxygen, ozone is detectable by planetary spectra, signature of much more advanced state of biological activity
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microlensing-
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depends on general theroy of relativity-geometrical theory of gravity mass distrots space around it
as mass warps space light follows -can detect earth sized objects -once you see it you never see it again -due to the gravity of a planet of a pasing star must pass in front of background star |
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lagrange points
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-where gravity cancels to 0
trojan places where astroids congregate |
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parent body of meteor
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astroid
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Carbonaceous chondrite
shape,size, D, K, primitive? |
irregular
small 3 made of rock .4 not differentiated Prim? yes |
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Ordinary Chondrite
shape,size, D, K, primitive? |
Ir
a little bigger than CC 3 .38 a little less prim than cc (partially dif) |
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A chondrites
shape,size, D, K, primitive? |
Spherical
large 3 .35 no (diff) |
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Stony Iron
shape,size, D, K, primitive? |
closer to SP
lg 5 rock and Iron <.4 no |
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Iron
shape,size, D, K, primitive? |
SP from core
lg 8 Iron <.4 No |
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Kuiper Belt
shape,size, D, K, primitive? |
IR
sm 2(ice and rock) .4 Yes prim |