Our Moon

Flashcards about the moon

Luna

Earth's only natural satellite

Highlands

Relatively bright areas on the moon

Plains

Darker areas on the moon

Orbital Period

The moon orbits the earth in this amount of time.

Rotational Period

The moon spins on its axis in this amount of time.

Perigee

Moon's closest point to Earth in its orbit

Apogee

Moon's farthest point from Earth in its orbit

Dark Side of the Moon

Side of the moon we cannot see from Earth

Accretion Theory

Theory that the moon formed at the same time as Earth

Capture Theory

Theory that the moon formed elsewhere and was captured by Earth's gravity

Giant Impact Theory

The widely accepted theory that the moon formed from a collision between Earth and a Mars-sized object

Moonlight

The light of the sun reflecting off of the moon.

Terminator

The line separating the dark and light sides of the moon

Phases of the Moon

The different apparent shapes of the moon as seen from Earth

New Moon

Phase when the moon and sun are on the same side of the Earth

Waxing Crescent

Phase when the moon's visible portion is increasing

First Quarter

Phase when half of the moon's face is visible

Waxing Gibbous

Phase when the moon is growing larger after the first quarter

Full Moon

Phase when the entire face of the moon is visible

Waning Gibbous

Phase when the moon is shrinking after the full phase

Third Quarter

Phase when half of the moons face is visible after the full moon

Waning Crescent

Phase when the visible portion of the moon continues to shrink

Eclipse

When one object blocks light from another object

Lunar Eclipse

An eclipse of the moon when it passes through Earth's shadow

Penumbra

The outer, lighter part of Earth's shadow

Umbra

The totally dark, inner part of Earth's shadow

Solar Eclipse

An eclipse of the sun when the moon passes between Earth and the Sun

Partial Eclipse

A solar eclipse where the moon partially covers the sun.

Annular Eclipse

A solar eclipse where a ring of the sun's surface is visible around the moon.

Total Eclipse

A solar eclipse where the moon completely covers the face of the Sun

Tides

The rising and falling of the oceans

High Tide

The point in the tidal cycle when sea level is at the highest point on land

Low Tide

The point in the tidal cycle when sea level is at the lowest point on land

Tidal Current

The direction the water is moving as it moves toward high or low tide

Flood Current

When sea level is rising toward high tide and water flows to the shore

Ebb Current

As sea level drops and the water is flowing back toward the ocean

Spring Tides

Extreme tides that occur when the Earth, Sun, and Moon are in a line

Neap Tides

Weak tides that occur when the gravitational forces of the Moon and Sun are perpendicular