Earth, moon and orbits

accretion

the process of gas, dust, and other particles accumulating to make the planets and stars

solar wind

blew away gases leaving heavier materials to make Earth

water

formed on Earth due to comets hitting Earth and ice melting

gases

got trapped by Earth’s gravity, forming our atmosphere

lighter, less dense materials

formed outer layers of Earth

heavier, more dense materials

formed inner layers of Earth

meteorites

are studied and provide evidence of early space materials

oxygen evidence

tells us moon rock and Earth rock are made of same stuff

rock dating evidence

tells us Earth rock is a little older than moon rock, but both formed at around the same time

Giant Impact Hypothesis

Theory that forming Earth got hit by a giant planet “Theia”, some parts stuck together and some flew off, forming the moon

eccentricity

how far an orbit deviates from a perfect circle

ellipse

shape of an orbit

foci

the two center points of an ellipse, one focus is the sun

gravity

stronger when objects are closer

speed

faster when planet is closer to the sun

perihelion

position of planet when closest to sun

aphelion

position of planet when farthest from sun

equal

the areas of space made from line to the sun in equal periods of time (pie shapes)

volcanoes

part of Earth’s second atmosphere, put CO2 and H20 vapor into atmosphere

rain

happened because atmosphere cooled and water vapor fell and formed the oceans

oxygen

went up in the atmosphere as a result of algae beginning photosynthesis

carbon dioxide

levels decreased due to being absorbed by oceans and plants

20%

amount of oxygen in today’s atmosphere

80%

amount of nitrogen in today’s atmosphere

less than 1%

amount of carbon dioxide in today’s atmosphere

1 AU

The distance from Earth to Sun

Greater than 1 AU

DIstance of planets farther away from the sun than Earth

Less than 1 AU

Distance of planets closer to the sun than Earth