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3 476 km is the diameter of the


the Moon's average density

3.3 g/cm3

gravity of Moon is

1/6 of Earth's

The Moon's interior structure is similar to earth's and has


The Moon turns on its axis

per revolution around Earth

T/F: the same side of the moon always faces earth


lighter areas of the Moon

lunar highlands

darker areas of the moon are



great basins and plains

collision theory

theory that states that the Moon was formed when a large, mars-sized object struck Earth about 4.6 billion years ago

about 1/6 of earth's mas was shot out into

Earth's orbit

Moon's formation was followed be a period of

meteorite bombardment

volcanic activity formed


the moon is estimated to have been formed about

4.6 bya

The age of the Moon is dtermined by

dating radioactive elements found in Moon rocks

lunar maria

large planes with hugh circular craters

the Moon is essentially the

8th continent

Lunar maria rocks resemble

bosalts from volcanic flows in Hawaii


"mas contractions"

lunar highlands

rocks are lighter- reflect more sunlight

lunar mountain ranges are found at the edges of the


Anorthoclase gabbro

rough, crystalline igneous rocks

lunar breccias

made of angular fragments and natural glass cemented together


indentations on the moons surface caused by meteorite impacts

craters were formed on the moon during

the bombardment period in the solar systems early history

craters shape

roughly circular with raised rims


rough streaks radiating away from craters

lunar soil id made up of

smaller rock pieces, dust, and natural glass


loose, rocky materials

regolith color


T/F:The moon has no organic matierial but has water


lunar soil thickness

1-20 cm

moons orbit

revolves west to east around Earth in a elliptical orbit

moon's period of revolution

27.3 days

moon's average distance from earth

384 000km


when the moon is closest to the moon


when the moon is farthest from earth

moon's orbital plane

5 degree difference from earths orbit

moon rises in the


moon sets in the


the moon rises at a different time

each day

the moon moves 13 degrees in its orbit every day, causing the moonrise to be

50 minutes later each day

1 lunar cycle is equal to

29.5 days


from new moon -> full moon


from full moon -> new moon

phase cycle

new moon -> waxing crescent -> first quarter -> waxing gibbous -> full moon -> waning gibbous -> last quarter -> waning crescent -> new moon


change in the moon's appearence from day to day

phases of the moon are caused by

the moon orbiting around Earth

T/F: the same side of the moon always faces Earth


New moon -> new moon is

NOT 1 revelution

1 orbit around Earth takes

27.3 days

New moon -> new moon takes

29.5 days


total shadow


partial shadow

T/F: Earth and the moon do not cast shadows ito space


lunar eclipse

occurs when the moon passes into Earth's umbra

a lunar eclips only occurs durring

the full moon phase


when the moons orbit is perfectly aligned with Earth's orbit

Solar eclipse

occurs when the moons shadow reaches Earth's surface

durring a solar eclipse, positions on Earth's surface inside the umbra have

total darkness

annular eclipse

when the moon is at apogee and he umbra fails to reach earth's surface

durring an annular eclipse the sun appears

as a bright ring around the moon

solar eclipses only occur durring the

new moon phase

individual locations experience a total solar eclipse about once every

300 years


rhythmic rise and fall of the water level at the coast and extremities every day

tides are caused by

the moons gravity as water flows over the tidal bulge, the level changes

cyclic tides change every

6 hours and 12.5 minutes

spring tides

higher than average high tides, lower than average low tides

spring tides occur

when the moon, earth, and the sun are aligned

reap tide

lower than average high tides, and higher than average low tides

reap tides occur

when the moon, earth and the sun are at a 90 degree angle

the sun composed

composed of hydrogen and helium

Galileo was the first to decribe the suns


solar telescopes

project a real image of the sun into a darkened room for observations

suns diameter

1 380 000 km

the suns diameter is

110 times greater than earths

the sun rotates every

25-27 days

how long for sunlight to travel from the sun to earth

8 minutes 20 seconds

light travels at a speed of

3.0 x 10⁵m/s

suns outer tempurature

5 500 C

suns interior tempurature

15 000 000 C


apparent bright, yellow surface of the sun

photosphere is

about 400 km thick

photosphere is made up of

individual cells


1 500 km across and have a bright center with dark edges

granules are the tops to columns of gas formed in the



faint red hue around the sun

chromosphere is caused by

the formation of helium in the star


seen as a faint halo around the sun durring solar eclipses

solar prominences

huge flame-like arches of plasma that occur in the corona


magnetic distortions in the photosphere

sunspots appear as

dark spots on the photosphere

sunspots occur in


sunspots have a

magnetic field (contains North and South poles)

sunspots create

cool spots on the photosphere

sunspots are darker due to

less solar activity

may be a difference of 1 500 C between sunspots and the


sunspots move

left to right across the suns surface

sunspots were first described by


solar wind

current of electrically charged particles emmited by the sun

solar wind average speed

400 km/s

coronal holes

large tears in the corona caused be strong "gusts" of solar wind

solar flares

outbursts of light that rise up out of sunspots


charged particles interacting with earth's magnetic field

solar wind can cause

solar storms

solar storms disrupt

satellite and ground based electrical transmissions

solar fusion

the suns energy source

the suns core is a

nuclear funace

the suns core is converting

lighter elements into heavier ones

the suns core releases

large amounts of energy

the sun is currently converting

hydrogen into helium

"missing" mass is converted into


Einstein's theory of general relativity


all planets orbit the sun in

elliptical orbits


oval shape

T/F: some planets orbits are more eccentric than others


2 pieces of info to calculate eccentricity of an ellipse

1. distance between 2 foci of the ellipse
2. length of the ellipses major axis(longest part of the ellipse)

the greater the eccentricity of the ellipse

the flatter the object

the lower the eccentricity of the ellipse

the more circular it is

eccentricity values range from

0.0 (circle) to 1.0 (straight line)

usually planets move

eastward across the night sky

planet in greek


at times, some planets appear to move

westward across the night sky

retrograde motions caused by

earth "catching up" and "passing" other planets in their orbital paths

when retrograde motion takes place

planets appear to move backwards across the night sky

retrograde motion is similar to

cars passing one another on the highway

geocentric model

model of the solar system with earth at the center and the planets and stars orbitiing it

geocentric model hypothesized by



less ertially "mini-orbits"

geocentric model show earth at

the center of the universe

geocentric model is made from

earthbound observations

heliocentric model

model of the solar system with the sun at the center with the planets and moons orbiting it

heliocentric model is the

current model

heliocentric model is made from

earthbound and spacebound observations

heliocentric model established by


Tycho Brahe

danish nobleman who made the 1st long-term observation of the night sky (about 20 years' worth)

Keplers 1 law of planetary motion

planets travel in elliptical orbits around the sun with the sun at 1 focus (a circle has 1 focus whereas an eclipse has 2 foci)

equal area law

each planet moves around the Sun in such a way that an imaginary line joining the planet to the sun will sweep over equal areas of space in equal areas of time

The speed at which a planet travels around the sun is not


planets travel rapidly when they are closer to the


law of harmonic motion

the amount of time it takes a planet to complete one orbit around the sun

the sequence of the period is equal to the distance between the

planet and the sun

period must be in

Earth years


astonomical units

distance between earth and sun

149.6 million km

the farther a planet is from the sun, the greater its

period of revolution

Dark line spectra can be used to

to show the composition of a stars or planets atmosphere

asd the center of the star gloes, light passes through


some light is obsorbed as it passes through the planets


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