Earth in Space Chapter 7

Section 1—Earth

Objects in Space In the past, people thought objects in space moved around Earth. But…these motions are really caused by Earth’s movements.

Spherical Earth Pictures from space show that Earth is shaped like a ball, or a sphere.

Evidence for Earth’s shape More proof of Earth’s shape is that Earth casts a curved shadow on the Moon during a lunar eclipse. Something flat casts a straight shadow, whereas objects with curved surfaces cast curved shadows.

Well, Almost a Sphere Earth’s shape is not a perfect sphere. It bulges slightly at the equator and is somewhat flattened around the poles.

Gravity Gravity is a force that attracts all objects toward each other. This is true of the Earth, or any two objects.

Tides It is the gravity of the moon and the sun that cause tides. Tides are a rise in sea levels, or a lowering of sea levels (known as high tide or low tide). YouTube Video explaining how tides work.

Tides When the moon is a new moon or full moon, you have Spring Tides. When the moon is at the first or third quarter, you have Neap Tides. YouTube video

Rotation The spinning of Earth on its axis, called rotation, causes you to experience day and night. One rotation takes 24 hours.

Revolution The Earth also moves along a path around the Sun. This is called a revolution.

Seasons Why is it cold in the winter and warm in the summer? The tilt of the earth.

Solstice This happens twice a year. It is when the sun is farthest away from the equator to the north or south. In the winter, this means we have the “shortest” day and in the summer, we have the “longest day.

Equinox At an equinox, when the Sun is directly above Earth’s equator, the lengths of day and night are nearly equal all over the world

Section 2—Moon

Craters & Maria Craters are impressions formed by large meteorites—space objects that strike the surface. Maria was formed because lava from the Moon's interior flooded bowl-like regions on the Moon's surface.

The Moon’s Interior Compared with Earth, the Moon is most like Earth’s outer two layers. This supports a hypothesis that the Moon may have formed primarily from material ejected from Earth’s mantle and crust.

Motions of the Moon The same side of the Moon is always facing Earth.

Revolution and Rotation It takes 28 days for the Moon to complete one orbit around Earth. The Moon also takes 28 days to rotate once on its axis.

How can we see the moon? You see the Moon because it reflects sunlight. However, we can’t always see the reflection of the sun.

Moon Phases What you do see are phases.

In what day of the next month would you expect a full moon?

PHASES OF THE MOON

New Moon New moon occurs when the Moon is positioned between Earth and the Sun.

Waxing Crescent

First Quarter

Waxing Gibbous

Full Moon

Waning Gibbous

Last Quarter

Waning crescent

Eclipse Eclipses occur only when the Sun, the Moon, and Earth are lined up perfectly. There are two types of eclipses Solar Lunar

Solar Eclipse During new moon, if Earth moves into the Moon’s shadow, a solar eclipse occurs.

Solar Eclipse Only areas on Earth in the Moon’s umbra, or the darkest part of its shadow, experience a total solar eclipse. Those areas in the penumbra, or lighter part of the shadow, experience a partial solar eclipse

Solar Eclipse Video

Lunar Eclipse A lunar eclipse occurs when the Sun, Earth, and the Moon are lined up so that the full moon moves into Earth’s shadow.

Lunar Eclipse Video

Solar System Our solar system is composed of the Sun, planets, asteroids, comets, and other objects in orbit around the Sun. Solar means sun!!!

Planets The planets in our solar system can be classified as inner or outer planets. Inners are inside of the asteroid belt. Guess where outers are located 

Inner Planets Mercury Venus Earth Mars (known as the red planet) They are also called terrestrial planets

Outer Planets Jupiter (largest planet) Saturn (known for rings) Uranus Neptune They are all gaseous giants

Other Objects in the solar system Asteroids are small, rocky objects mostly between Mars and Jupiter. Comets are made mainly of rocky particles and water ice.