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CHAPTER 7

7.1 EARTH MOTION AND SEASONS

A. Earth’s Physical Data

1. spherical shape (almost)

2. bulges at equator

3. gravity = 9.8 m/s

4. Table 1 (page 180)

B. Earth in Motion1. axis- imaginary line drawn from the

north to south pole2. rotation- Earth spinning around on its

axis -causes day and night

3. revolution- Earth traveling around the sun

-elliptical pattern is an orbit-causes seasons-not a whole # of days (365 ¼)

4. tilt- 23.5 degree angle-hemispheres have opposite seasons-regions near equator have equal

hours of day and night all year

5.Solstice- sun reaches it’s greatest distance north or south of the equator directly over the Tropic of Cancer or Tropic Capricorn

a) Summer Solstice-sun is highest in the sky at noon-longest day of the year for us-June 21st in the N. hemisphere-Dec. 21st in the S. hemisphereb) Winter Solstice-sun is lowest in the sky at noon-shortest day of the year for us-Dec. 21st in the N. hemisphere-June 21st in the S. hemisphere

6. Equinox- sun is directly over equator

-length of day and night are equal all over the world

a) Spring Equinox-March 21st in the N.

Hemisphereb) Fall Equinox-Sept. 21st in the N.

Hemisphere

7.2 EARTH’S MOON

A. Moon’s Surface Features1. Maria- dark colored areas that

look like oceans formed by lava flows

2. Lunar Highlands- higher than the maria

3. Craters- depressions formed from meteorites striking the surface

B.Layers of the Moon1. Crust2. Rigid Mantle3. Non-rigid Mantle4. Small, dense

core

C. Motions of the Moon-the moon always keeps

the same side facing the Earth-27.3 days to orbit the

Earth-27.3 days to rotate once

on its axis

D. MOON PHASES (refer to worksheet)

1. New Moon2. Waxing…grows in

size3. Full Moon4. Waning…decreases

in size

E. ECLIPSES1.Definition- shadows cast by Earth or the

moon onto each other

-only occur when the sun, moon, and Earth are perfectly lined up

2.Solar Eclipse

-moon blocks sun from reaching a portion of the Earth’s surface

-occurs during a new moon

3.Lunar Eclipse

-Earth blocks sun from reaching the moon

-moon appears deep red

F. ORIGIN OF THE MOON

1.Co-formation- Earth and Moon formed at the same time from the same material

2.Capture- Earth and moon formed at different locations, then Earth’s gravity captured the moon

3.Fission- moon formed from a large mass of material thrown off of a rapidly spinning Earth

4.Collision- a huge space object collided with Earth, throwing large amounts of gas and debris into orbit around Earth….condensed to form moon

7.3 OUR SOLAR SYSTEM

A. SOLAR SYSTEM• Sun

• Planets• Asteroid

s• Comets• Moon• stars

May have formed from a cloud of rotating ice gases and dust calleda “nebula”

B. ASTRONOMICAL UNIT (AU)

1. Distance between Earth and Sun

2. Used to measure distances between objects within the solar system

C. SUN

1.The sun is a star.2.It produces energy by fusing hydrogen into helium in it’s core.

3.It contains more than 99% of all matter in our solar system.

D. OTHER OBJECTS1.Asteroids- small, rocky objects

that lie in a belt between Mars and Jupiter

2.Comets- made of rock particles and ice

-as they approach the sun, parts of comets vaporize and form tails that point away from the sun

3.Meteoroids- pieces of comets or asteroids that travel through the solar system

a. Meteoroid- rock in spaceb. Meteor- rocks entering Earth’s atmospherec. Meteorites- rocks fall and land

on Earth

COMET IMAGES

E. PLANETSMercury - solidVenus - solidEarth - solidMars - solidJupiter - gaseous

Saturn - gaseous

Uranus - gaseous

Neptune - gaseous

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