astronomy 2 Flashcards
what is the difference between rotation and revolution
rotate-spin
revolution-motion around another object
what does earths rotation produce
night and day
how do we know earth rotates
Foucaults pendulum - earth rotates beneath it
what is earths orbit shape
elliptical
how do we know the earth revolves around the sun
parallax- shift in position of a nearby star
why do we see different constellations
because we revolve around the sun
see constellations that are opposite the sun
what are seasons caused by
earths revolution
earths tilt
what way is the earth tipped during summer and winter
toward the sun
away from the sun
what is precession
movement of earths axis
axis wobbles slowly over time
when is the sun highest and lowest in the sky
highest on the summer solstice
lowest on winter solstice
where does the sun rise and set on the equinoxes
the fall and winter the spring and summer
exactly in the east and west
sun rises SE and sets SW
rises NE and sets NW
what is the celestial equator
projection of earths equator in space
at the earths equator the celestial equator is directly overhead
what is the ecliptic
the path the sun travels in the sky
zodiacs located along the ecliptic
what is altitude
angle of the sun above the horizon
no direction on altitude
what is moon phase
the amount of the moon that is visible from the earth
waxing-revolving toward full
waning-revolving toward new
how long does it take for the moon to revolve around the earth
moon revolves around earth in 29 days- full moon to full moon
why does the moon rise and set
because the earth rotates
what is an eclipse
an eclipse is when an object in space passes into the shadow created by another object in space
umbra-total shadow
penumbra-partial shadow
types of lunar eclipses
total lunar eclipse-moon passes into earths umbra
partial lunar eclipse-moon passes into earths penumbra
types of solar eclipses
total solar eclipse-moons umbra falls on the earth
partial solar eclipse-moons penumbra falls on the earth
annular eclipse- ring is visible moon doesn’t quite cover the sun
how did the moon form
formed from a collision with a mars sized object
debris from collision accelerated into the moon
surface bombarded by meteorites
properties of the moon
gravity 1/6 of earths
rocks are igneous
average density is less than earths
mass is about 1/80 of earths
dark area of moons surface
maria-basins of basaltic rock 3.1-3.8 billion years old
lighter areas of moons surface
lunar highlands-on the edge of maria 4.0-4.30 billion years old
what causes tides
moons gravity and earths rotation
what is solar noon
occurs when the sun is at its highest point
does not occur at the same time for everyone
earth rotates 15 degrees per hour
every degree of longitude is 4 minutes of solar time
4 different time zones
eastern
central(-1)
mountain(-2)
pacific(-3)
what is the international dateline
180 degrees meridian
day starts and date changes when crossing it
moving west-add a day
moving easy-lose a day
what is a solar system
objects in orbit around the sun
includes:
planets, moons, asteroids, comets
greeks early solar system model
greeks thought that all planets orbited the earth
geocentric model
solar system formation
proto-planetary disc -cloud of gas and dust
gravity pulls particles together
sun forms-fusion of hydrogen
planets form from remaining material through accretion
inner planets
four planets nearest the sun contains heaviest elements have solid surfaces dense cores mercury,venus,earth and mars
asteroid belt
rocks and dust between mars and jupiter
debris never became a planet because of Jupiter’s gravity
outer planets
four planets beyond asteroid belt jovian planets or gas giants no solid surface made up of gases solid cores Jupiter, Saturn, Uranus, and Neptune
kuiper belt
belt of debris at the edge of the solar system
dwarf planet pluto is the most massive object in belt
which planet is the most massive
jupiter
which planet have rings
saturn
what is olympus mons and valles marineris
volcano extinct on mars
huge canyon on mars
what holds planets in their orbits
the suns gravity
phases of the moon in order
new moon waxing crescent first quarter waxing gibbous full moon waning gibbous last quarter waning crescent
