Astro 7N Unit 2

heliocentric

having the sun as the center

geocentric

having the earth as the center

kepler's first law

orbit of each planet is an ellipse with the sun at one focus of the ellipse

kepler's second law

planet's speed is fastest when closest to the sun (perihelion) and slowest when farthest away (aphelion)

kepler's third law

P^2 = a^3

mercury size compared to earth and mars

much smaller than earth; very similar to mars

mercury gravity

less than on earth

mercury temp and why

extremely high on day side and extremely low on night side
*due to lack of atmosphere - can't distribute heat evenly*

mercury terrain

many craters that are cold cold cold
some hold ice deposits

mercury rotation

SLOW - short year

venus size

lil smaller than earth

venus rotation

- longer rotational period than year
- opposite direction to orbit around sun
- sun travels west to east

venus atmosphere and why

- mostly CO2 and gases
- produced by volcanic outgassing
- sulfuric acid in clouds :/

venus made of...

metals and rocks

venus terrain

volcanoes, large lava flows, large craters

venus temp and why

HOT -> lots greenhouse gases contain heat

earth atmosphere

- N and O molecules
- scattered light from sun gives daylight

aurora

solar wind particles hit atmospheric gas and lead to emission of different colors -> north and south poles!

plate tectonics

- rocky plates on surface of earth move around
- leads to continental drift, mountains from collisions, quakes

ozone layer

protects earth from solar UV radiation; can be destroyed by certain gases from human activity

greenhouse effect

gases capture heat and send it back to earth and warm earth

Terrestrial Planets (TPs)

mercury, venus, earth, mars

terrestrial planet size

earth sized or smaller

TP length of day

long day, slow rotation

TP year length

short (close to sun)

TP distance from each other

close

TP density

high - made of rocks and metals

TP temps

variable but warmer towards sun

TP rings?

none

TP moons

few or none

Jovian Planets (JPs) - gas giants

jupiter, saturn, uranus, neptune

JP size

much larger than earth

JP day length

short day, fast rotation

JP year length

LONG

JP distance from sun

FAR

JP distance to each other

V FAR

JP density

low - gases!

JP temp

v cold cold cold

JP rings?

yes all of them!

JP moons

many

earths moon terrain

terra and maria
no atmosphere
dark

terra

light colored features, heavily cratered, high peaks, older

maria

dark colored, less cratered, valleys, younger, filled by lava

regolith

powdery dust and rocky debris covers Moon

impact craters =

gouged out from explosions, astroids or comets

earth moon rotation

same side always faces earth

earth moon lacks...

high density material

surface gravity on earths moon

6X larger on earth than moon

mars day and night

similar to earths

mars size

half earths diameter; 1/10th earths mass

mars atmosphere

- supa thin -> causes orangish sky
- mostly CO2
- modest greenhouse effect bc thin

what gives mars its red color?

iron oxide aka rust

mars moons

phobos and deimos - v tiny (like laila)

olympus mons

volcano on mars 3 times higher than earths highest

valles marineris

deepest canyon in solar system; 300 times size grand canyon

water situation on mars

- once existed but doesn't flow regularly
- permafrost = water ice locked beneath martian soil

mars weather

dust storms common

jupiter size

300x mass but less dense and 11x radius than earths

jupiter rings

small ring system

jupiter made of...

- H and He gas
- ammonia, methane lead to diff colors in swirls

Great Red Spot

giant storm on jupiter larger than earth; been around for like 300 years

jupiter weather

WINDY AF

jupiter rotation

RAPID -> clouds stretch into long bands, long orbit tho

jupiter core

likely rocky/metallic (H compressed - high temps and pressures)

jupiter magnetic fields and why

10x stronger than earth due to rotating liquid-metallic region

jupiter diamond rain

methane converts to carbon soon and high pressures compress this into diamonds !

jupiter life forms?

proposed to exist; sinkers floater and hunters

jupiter moon

lo, europa, ganymede, anc callisto

lo

- closest
- coppery yellow (sulfur) w black dots (active volcanoes - tidal heating)
- low crater density

europa

- water-ice surface
- no craters
- liquid water ocean below icy crust

ganymede

- largest moon eva
- icy crust
- craters -> once active but not now

callisto

- farthest out
- heavily cratered
- not really heated

saturn rings

thin, made of trillions of individual orbiting objects (dusty water ice crystals)

saturn size

100x mass earth, 10x radius earth

saturn density

LOW LOW LOW LOW - shit can float!!

saturn axis

same as earth

saturn composition

- H and He
- clouds in belts an zones

saturn temp

colder than jupiter

saturn moons

more the 50 -> LARGEST = TITAN (2nd largest in solar system and v N-rich)

uranus size

3rd largest

uranus orbit

84 years

uranus atmosphere

- H and He gas, some methane (blue-green color)
- liquid icy core surrounding smaller rocky core

uranus spin axis

rolling on its side basically -> caused from collision early in history; continual darkness at poles 42 years in a row

neptune color

deep blue

neptune atmosphere

- H, He, and methane (blue)
- solid core (earth sized) surrounded by mantle of semi fluid ices

neptune weather

rapid winds and large storms/vortices, including great dark spots

neptune rings

faint and dark made from clumps of dust

neptune moons

LARGEST = TRITON -> thing atm of N and methane, rocky, reflective, volvanoes
unusual orbit -> may be captured kuiper belt object

pluto size

very small

2 reasons pluto isn't a planet anymore

1. other similar objects found farther from the sun
2. not like other outer planets (small ice dwarf)

what is pluto now considered?

dwarf planet in kuiper belt

kuiper belt

disk shaped region beyond neptune

Oort cloud

houses long period comets beyond kuiper belt

Requirements to be a planet (3)

1. orbit sun
2. massive enough to be nearly round
3. clear region around its orbit

when was solar system formed?

4.5 billion years ago

how did solar system form?

1. cloud of gas and dust collapses
2. spinning cloud flattens and forms disk
3. sun forms at center
4. lumps in disk become planets
5. regions around clear out
6. rocks and metals survive in inner region; ices and gases outter

how long did it take for solar system to form?

few tens of millions of years

Remnant of the formation of the Solar system

asteroid + comet + meteor

shine because of reflected sunlight

asteroid + comet

kuiper belt or oort cloud

comets