1. The Earth in Space

2. Physical properties of Earth
diameter (equator)- 12,756 km
diameter (poles)- 12,714 km
circumference (equator)- 40,075 km
average distance from sun- 149,600,000 km

3. In The Past
people thought the sun, moon, and stars orbited around the Earth
thought the Earth was flat

4. Earth’s Motion and Seasons
Earth’s tilt has fluctuated throughout geologic time from 21.5o- 24.5o.
above the Arctic Circle receive 24 hrs. of daylight
below the Antarctic Circle 24 hrs. of darkness
Precession- Earth’s axis wobbles in a large circle that that takes >26,000 years to complete.

5. Earth’s Motion
Solstice- sun reaches its greatest distance from the equator.
Equinox- days and nights are equal length.
When the northern hemisphere points towards the sun we experience summer.

6. Solstices northern hemisphere- June 21st
southern hemisphere- December 21st

7. Equinoxes northern hemisphere- March 21st
southern hemisphere- September 21st

9. Earth’s Moon
probably formed when a large object collided with Earth shortly after it formed
moon rocks range from billion years
crust, mantle, and solid iron core
craters- form when meteorites strike the moon

10. Moon Craters

11. Why can you not see craters as well on Earth as on other baron planets and moons?
Water (oceans) covers the craters.
Water erodes the crater’s edges and obscures them from view.
Vegetation (forests) covers the craters from view.
Clouds/Atmosphere make the Earth’s surface less visible from space.

12. The Barringer Crater near Winslow, Arizona
The Barringer Crater near Winslow, Arizona. The crater is about 49,000 years old.

13. Lunar Motion The same side of the moon always faces the Earth.
distance from earth- 384,000 km (238,606 miles)
complete orbit takes 27.3 days

14. Solar Eclipse
occurs when the Earth moves into the moon’s shadow

15. Lunar Eclipse occurs when the sun, Earth, and moon line up.
the full moon moves into Earth’s shadow.

16. The Moon’s Formation co-formation hypothesis capture hypothesis
collision hypothesis

17. Our Solar System composed of sun, planets, asteroids, and comets
>99% of all the solar system’s matter is contained in the sun

18. Planets Inner Planets Outer Planets Jupiter Mercury Venus Earth Mars
Saturn
Uranus
Neptune
Pluto
Mercury Venus Earth Mars

19. Asteroids and Comets
asteroids are small, rocky bodies that lie mostly in a belt between Mars an Jupiter.
comets are made mostly of rock and ice

20. Origin of the Solar System
The sun and planets probably condensed from a nebula (large cloud of gas, ice, and dust) about 5 billion years ago.

21. Andromeda Galaxy