Crater

A bowl shaped depression on the surface of a moon or a planet usually caused by the impact of a meteor.

Meteoroid

Rocky or icy fragment that travels through space

Micrometeoroid

Tiny rock fragments no larger than grains of sand that travel through space

Mascons

Areas of higher gravity that exist over lunar maria; short for mass concentrations

Maria

Extensive dark areas on the moon that represent great basins and level plains

Rille

Ray

A bright streak of shatter rock and dust that radiates from a lunar crater.

Regolith

A grayish brown mixture of small rock pieces and fine particles that covers the moon.

Phases

The daily changes in the moons  appearance as it is viewed from earth

Waxing

The increasing visibile amount of the moon’s illuminated surface from a new moon to full moon.

Waning

The decreasing visible amount of the moons illuminated surface from a new moon to full moon

Gibbous

A phase of the moon in which almost all of the bright half of the moon faces earth.

Umbra

The darkest part of the shadow cast by the moon or by the earth

Preumbra

The area of partial shadow surrounding the darkest part of the shadow of the earth or moon.

Lunar eclipse

The eclipse that occurs  when the moon passes into earth’s total shadow or umbra preventing sun from reaching the moon it occurs only at the full-moon phase

Solar eclipse

The eclipse that occurs when the moon passes between the sun and earth and moon’s shadow strikes earth’s surface.

Tides

The periodic rise and fall of the ocean surface due to gravitational pulls of the moon and the sun

Spring Tide

a tide of large range occurring at the new moon and full moon

Neap Tide

A tide of small range occurring at the quarter phase of the moon

Perigee

The point closest to the earth in the moons orbit

Apogee

The point farthest to the earth in the moon’s orbit.