Planetary Science Flashcards
Heliocentric
We orbit the sun
Geocentric
The sun orbits us
Aristotle
Geocentric
It doesn’t explain retrograde motion of Mars
Ptolemy
- explains retrograde motion
- epicycles
- –2 motions (around earth, around a point in space) (like Pluto)
Copernicus
Heliocentric model
- different planets orbit at different speeds and distances
- explains retrograde motion
Galileo
- probes heliocentric model with scientific data
- created compound telescope and looked up
Brahe
- astronomy’s first observer
- observations of stars + planet positions
- did NOT believe heliocentric model
Kepler
- brahe’s student
- proved heliocentric model with math using Brahe’s data
- had 3 laws
Newton
You know him
Gravity
Distance between planets farther out
Gets way bigger
Gravity is weaker
Kepler’s 1st law
Law of ellipses
-elliptical orbits
(See diagram)
Kepler’s second
Law of equal areas
- sweeps out same area in same time
- faster close to sun
- earth is ALMOST circular
Kepler’s third
Law of periods -k•r^3 = p^2 k = constant p = period r = radius (mean distance to sun)
Orbital eccentricity
How much an orbit differs from a circle
Apogee
Point an object orbiting something is at its farthest point
Perigee
Point where an object orbiting something is closest to it
How big is the moon
27% earth’s size (about 1/4)
How far away is the moon
384 000km
Why do we always see the same face of the moon
Rotation and Revolution is the same length
Why do we have phases of the moon
Earth blocks the sun
Regolith (moon)
Dusty blanket of meteorites that landed on moon
Highlands (moon)
Mountains (rings around craters)
1000s of feet tall
Lowlands (moon)
Craters + Maria/seas (lava filled basins, hardened
Tides
- caused by moon’s gravity
- bay of Fundy has huge tides (55 feet)
Moon’s gravity does what?
- tides
- keeps earth’s axis constant
Moon theory: co-creation
Grew up together
-but moon has lower Fe content
Moon theory: fission
Molten earth spun off
- can’t do math closer than 5 revolutions a day
- earth is too fast for current speeds
Moon theory: captured
Like Jovian moon’s
-earth’s gravity is too weak
Moon theory: giant impact
Mars sized rock crashed
-most accepted
Challenges with coming up with a theory on how the solar system was formed
- categorizing planets
- patterns of motion
- asteroids + comets
- exceptions
Best theory on how solar system was formed?
Solar nebular theory
-evidence is protoplanetary disks elsewhere (beta pictoris)
Protosun
Hot ball of gas becoming the sun
Protoplanet
Matter becoming a planet
Interstellar dust
Dust between stars
Fragmentation
Small objects -> smaller objects
Swept by protoplanets
Gravitational coalescence
Stuff coming together because gravity
Mercury
- smallest
- difficult to study because it’s so close to the sun (we see it 13x a year)
- resembles earth’s moon
- 1 year = 88 days
- -173-427 C because no atmosphere
- eccentric orbit
Venus
- similar to earth
- hottest planet
- no moon’s
Mars
- Rocky, dusty, cold
- less gravity than earth
- explored with spacecraft, satellites, Rovers
Jupiter
- shortest day (9:55) (fastest spinning)
- great red spot been going on for 350 years
- magnetic field 14x stronger than earth’s
- tilt of 3 - no seasons
- 80x more massive = it’s a star
Saturn
- least dense
- 62 moon’s
- rings disappear
- could be life on moon’s
- 1 year = 30 earth years
- can be seen with naked eye
- fastest planet
- Jupiter-style storms
Uranus
- 27 moons, 13 rings
- made of ice (ice giant)
- rotates at nearly 90 degrees (spins on side)
- atmosphere mostly H + He
- min temp of 49K (-224.2 C)
Ceres
- largest object in asteroid belt
- only dwarf planet in inner solar system so far
- 25% water (has more water than earth)
- thin atmosphere
- may harbour life (micro organisms/bacteria)
- size of Texas
- 1 year = 4.6 earth years
Eris
- 1 year = 557 earth years
- one known moon (Dysnomia)
- sometimes closer than Pluto to the sun
- surface is icy
Makemake
- 3rd largest Kuiper Belt Object
- doesn’t have an atmosphere (usually)
- methane, ethane, nitrogen ice
- one discovered moon
- named after God of fertility/created of humanity of Rapa Nui myths (Easter Island)
- 1 day = 7.7 hours, 1 year = 310 earth years
Sedna
- beyond Kuiper belt
- supposedly in Oort Cloud
- no moon’s
- cold, small, far away
- half the size of the moon
- miner planet (can’t confirm that it’s a sphere)
- very elliptical orbit
Meteoroids
- stuff flying around (parts of asteroids and comets broken off)
- size of pebble
- appear everywhere
Meteorite
Meteoroid that hits the ground
Asteroid
- star-like
- irregular shaped dust + gas
- some have gravity, some don’t (all smaller than a planet)
- Trojan asteroids (beside (in front/behind) planet)
Comets
- dust
- gas
- ice
- short period (<200 years)
- long period (>200 years)
Kuiper belt
30-55AU asteroid belt
Oort Cloud
Cloud of ice and dust beyond Kuiper belt (comets)
Sun layers (bottom to top)
Core Radiative zone Convective zone Photosphere Chromosphere Corona
Suns core
Nuclear fusion
Sun radiative zone
Energy transfer by radiation (photons)
Sun convective zone
Energy transfer by convection (plasma)
Sun photosphere
Where hot gases rise and give off heat
Sun chromosphere
Outer atmosphere
Sun corona
Aura of plasma around sun
Solar prominence
Bright, large feature from photosphere Coronal loops -some last for hours/days -100 000km long (some 500 000km) Magnetic field Causes solar flares + CMEs
Solar flare
Sudden, intense energy release
- a few mins, some over an hour
- can be 35x earth’s diameter (most 7x ish)
- cause CME’s, knock out comms + radio
- from twisted magnetic field
- sun quakes when big enough
CME
Release of plasma + magnetic field
- can reach earth in 14-17h
- very big (mass of Mt Everest)
- earth’s magnetic field protects us
- power outages, radiation, comms down
Sunspots
Reduced temp areas from twisted magnetic field (no convection) (1000 degrees)
- last 11 years
- most from 1500km-50 000km in diameter
- become prominences/flares/CMEs
- can twist like Great Red Spot
- 1st proof that sun rotates
Solar wind
Continuous flow of charged particles from sun
- will last all of Suns lifetime
- causes light, part of CMEs
- big (goes in all directions)
Coronal streamers
Wisp-like stream of particles through corona
Solar max/min
Every 11 years - period of high/low solar activity
Alfvén waves
Hydromagnetic shield waves in plasma along magnetic field lines (ions oscillate in response to restoring force)
Halo effect
Hall ring around sun/moon at 22 angle
Ice crystals in cirrostratus clouds
Heliosphere
Region of space where sun has influence
Ozone layer
Blocks most of Suns UV light on earth
Gamma ray burst
Photons (I mean really)
Hinode
- sun
- study of magnetic field
- HD photos of sum
- magnetohydrodynamics
- explained why Suns angular momentum differs
- Japanese
MESSENGER
- Mercury
- NASA
- to explore Mercury (it’s dense, it has useful metals)
- it has buried water, varied temps
- may be shrinking
- tectonically active
Venera 4
- Venus
- USSR
- collected atmospheric data (90-95% CO2, 3000x weaker magnetic field, 7% N)
- 1st probe to send data from elsewhere
Apollo
- 107 degrees in day, -153 at night
- Mt Huygens is tallest (1/2 mt Everest)
- 12 Apollo missions (11 landed)
- Saturn V rocket was used to launch it
- moon
Opportunity, Spirit, Curiosity
- Mars
- to determine whether there’s life on Mars
- rovers
- characterize climate + geology
- prepare for human exploration
- thees water
- spirit is trapped in sand
- curiosity is still going
- Mars lost atmosphere over time
Dawn
- Ceres + vesta
- first probe to either
- vesta has 2 large craters + hydrated materials
- Ceres has H2O beneath surface, mineral deposits, maybe life
- going to asteroid 2 (Pallas), stay on Ceres
Juno
- farthest solar powered spacecraft
- reveals origin + evolution of Jupiter
- how planets formed
- atmosphere
- magnetic field map
- pics, solar panels, magnetometers
- great red spot, huge cyclones at poles
- Jupiter
Voyager 2
-Uranus and Neptune
-One of 1st probes to go beyond solar system
-to explore outer planets + beyond
Uranus: ocean, 10 moon’s, 2 rings, average temp, magnetic field
Neptune: 5 moon’s, 4 rings, dark spot, triton is coldest thing in solar system
New horizons
- Pluto
- answer questions about its moon’s and Kuiper belt
- US completion of solar system exploration
- evolutions of dwarf planets
- ice dwarfs
- 4 moon’s (ish)
Hubble Space Telescope
- cassegrain telescope
- to capture images from beyond earth’s atmosphere
- Jupiter (monitors red spot)
- saltwater on Ganymede
Rosetta
Comet 67P
- orbited and landed on comet for first time
- watching comet change during closest approach to the sun
- debate of origin of H2P on earth
Deep Impact spacecraft
- comet tempel 1
- flyby + impactor
- tempel 1 is fine dust held together with gravity
- increase of carbon containing stuff
- hasnt changed since early solar system
- helps understand comets
Exoplanets
Extra-solar planets
Trappist-1
Near earth objects
NASA tracks them
Sun’s max angle in sky
Latitude + 23.5 degrees
Who first introduced the concept of a heliocentric system
Copernicus
