Our Earth, Moon, and Sun

ASTRONOMY

BIG IDEAS

What causes the phases of the moon?

Compare the causes of solar and lunar eclipses.

Explain what causes the tides.

phases

lunar

solar

eclipse

gibbous

crescent

penumbra

corona

neap tide

spring tide

umbra

corona

WORD ATTACK

WHAT CAUSES THE PHASES OF THE MOON?

The phase of the moon you see depends on how much of the sunlit side of the moon faces Earth.

The moon revolves around Earth in the same amount of time the moon takes to rotate on its axis. As a result, the near side of the moon always faces Earth.

Current Moon Phase

VOCABULARY

Umbra – darkest part of the cone-shaped shadow

Penumbra – larger part of the cone-shaped shadow that is less dark

WHAT IS AN ECLIPSE?

An eclipse occurs when an object in space comes between the sun and a third object, and casts a shadow on that object.

There are two types of eclipses:Solar eclipses

Lunar eclipses

Earth is directly between the moon and the sun.

Earth blocks sunlight from reaching the moon.

Occurs during a full moon.

The moon passes between Earth and the sun.

The moon blocks sunlight from reaching Earth.

Occurs during a new moon.

COMPARE THE CAUSES OF SOLAR AND LUNAR ECLIPSES.

Solar Eclipse Lunar Eclipse

TOTAL SOLAR ECLIPSE

People within the umbra of the moon’s shadow experience a total solar eclipse

The sky is dark

They can see the stars

They can see the solar corona

The moon’s orbit is tilted 5º with respect to Earth’s orbit. So the moon rarely goes directly between Earth and the sun.

PARTIAL SOLAR ECLIPSE

People in the penumbra see only a partial eclipse

meaning part of the sun remains visible

Never look directly at the sun, not even when standing in the moon’s shadow

Eclipses of the sun should only be viewed through specially prepared viewing devices

VOCABULARY

What is the Umbra?

What is the Penumbra?

UMBRA AND PENUMBRA

TOTAL LUNAR ECLIPSE

The moon is in Earth’s umbra

Can be seen anywhere on earth that the moon is visible

PARTIAL LUNAR ECLIPSE

The moon passes partly into the umbra of Earth’s shadow

Earth, the moon, and the sun are not quite in line

The edge of the shadow appears blurry

A partial lunar eclipse can be viewed for two or three hours