the continents are moving but the ocean floor is not, leading to great friction

the rubbing of the waters of the Earth across its crust is speeding up its rotation

the liquid metal inside the Earth is developing plates of solid metallic material, which contribute to the Earth's magnetic field

earthquakes are caused by huge waves that come up from inside the molten core of the Earth

slow motions within the mantle of the Earth move large sections of the crust around

it is slowly leaking atoms into space from its outermost regions

its mass is a substantial part of the mass of the Earth

warm air rises and cool air descends within it, setting up circulating currents `

it is made mostly of nitrogen

one of its layers helps keep much of the ultraviolet radiation from space from reaching the surface

humans

fish

microscopic creatures, too small to see with our eyes

birds

insects

solid material hitting the Earth from space heats it up

carbon dioxide (and other gases) in the atmosphere causes a greenhouse effect

the rubbing of the continental plates warms up the Earth's surface

the heat given off by living things makes our planet warmer

we have no explanation for this higher temperature and that has scientists worried

the devastation that happened in 1908 near the Tunguska river in Siberia

Meteor Crater in Arizona

the crater at the top of the Mount St. Helens volcano

the Chicxulub crater buried near Mexico

you can't fool me; all the above are the results of cosmic impacts

the magnetism of the Moon is more likely to attract metallic objects to hit it

all objects from space (no matter what their size) burn up in the Earth's atmosphere

the craters on the Moon are the result of active volcanoes; the Earth has few volcanoes compared to the Moon

the active geology and weather on Earth destroy traces of impacts over millions of years

the Earth is heavily cratered, but all the craters are under the ocean

roughly the same size

similar atmosphere

same gravity on the surface

takes the same time to rotate on its axis

none of the above

Luke Skywalker

Buzz Aldren

James Van Allen

Neil Armstrong

have been formed in the same way as the mountains on the Earth

were formed through the eruption of volcanoes early in the Moon's history

were formed by the collision of continental plates early in the Moon's history

are the result of giant impacts during the Moon's long history of being hit

are a complete mystery, which astronomers have not been able to explain

it is sand, produced in exactly the same way sand is produced on the Earth's beaches

it is the result of volcanic activity on the Moon over billions of years

it is the result of many impacts, breaking surface rocks apart over billions of years

it is the result of gas bubbling up from inside the Moon, which chemically changes the surface soil

even though the astronauts brought home lots of samples of Moon dust, we have no idea why there is such a layer on the Moon's surface

a crater

an ejecta blanket

secondary craters

a rough hilly apron (or slope) of ejected material

lava flow

all the radioactive rocks found on the Moon so far give ages much younger than that, so the Moon must have formed less than 3.8 billion years ago

we see many more craters on the Moon that have been eroded by wind and rain

all the large craters on the Moon come in pairs, while all recent craters are single

there are ten times more craters on the older highlands than the younger maria

the ancient sea basins on the Moon, whose water has since evaporated, show a lot more cratering

the Moon came out of the Earth

the Moon was formed in the same area of space and at the same time as the Earth

the Moon was formed elsewhere and was later captured by the Earth

a large object hit the Earth and the collision produced a filament of material that condensed to make the Moon

the Moon was the gift of the Green Cheese Producers on Mars

cosmic impacts are always so slow, the bodies involved never break into pieces

the impactor was about the size of Mars or smaller, so it ejected material from the Earth but did not break it

the impactor was made of such light material (mostly gas and liquid) it could not break the Earth apart

there were more than a dozen small impactors, all hitting one after another

the Earth did break apart into many pieces, which then re-formed into a planet

its surface is heavily cratered

it has a significant atmosphere

the highest temperature on the two worlds is the same

the time they take to spin once on their axis is the same

you can't fool me, Mercury is not similar to the Moon in any way

because the Moon and Mercury have larger gravity than Earth, and this can attract larger pieces

because the Moon and Mercury do not have atmospheres to protect them from the largest pieces that can hit

because the Earth's magnetic field protects us from larger impacts

because the Moon and Mercury have much larger volcanic eruptions

because the largest craters were made early in each world's history, and geologic activity has erased all traces of this early period on the Earth's surface

Mercury was formed in the outer solar system and later wound up in its present orbit

giant impacts in its early history may have torn away much of its original crust and mantle

giant impacts early in its history added a tremendous amount of material to the original planet

a large satellite (made of the same material as the Earth's Moon) crashed into Mercury early in its history

Mercury was briefly inside the Sun, and thus lost much of its earliest material

it is always hot everywhere on Mercury, because the planet is so close to the Sun

it is always cold all over Mercury, because the planet has no significant atmosphere

one side of Mercury is always extremely hot, while the other side is about the same temperature as Los Angeles on Earth

the difference in temperature between Mercury's daylight side and its night side is the greatest difference of any planet in the solar system

we suspect Mercury must be warm, but we have not been able to measure any temperatures on the planet with our instruments

because the rocks and icebergs that fell from space to make them were all spherical

because the volcanoes that make them erupt in a symmetrical way, making circular openings for the lava to emerge

because the active surface of the Moon converts the craters into circular basins, no matter what shape they start out being

because the rocks and icebergs that hit the Moon are moving so fast, they explode on impact, making a circular hole

this is an unsolved mystery; it’s one of the most puzzling things about the Moon

At the bottom of all the craters we see on the side facing us

In the highlands, but only on the side of the Moon facing away from Earth

Deep inside craters in the regions near the Moon’s poles

In the maria, regions of the Moon that are water filled seas

You can’t fool me, no water has ever been found on the Moon in any form

its average density is less than that of the Earth (it seems to have fewer heavy materials)

most of what we know about its geology is the result of the Apollo landings

on Earth, we can see all its sides in the course of a month as it goes around us

its mass is less than that of the Earth

it has no real atmosphere to speak of

the Earth's core

the Earth's crust and mantle

comets

Jupiter and Saturn

no other body in the solar system

oceanic crust

continental crust

mantle

core

atmosphere

metamorphic

sedimentary

igneous

silicate

subducted

presses down on the continental plates, and makes it more difficult for them to slip

keeps the heat of the Sun from escaping, making the Earth a bit warmer

is so thick that meteors from space all burn up there, regardless of size

absorbs ultra-violet light, preventing much of it from reaching the surface

glows brilliantly at sunset, making scenes that lovers can enjoy

oxygen

ozone

water vapor

argon

nitrogen