1. Earth in Space
Chapter 7, Section 1

2. Earth’s size and shape Earth is a sphere How do we know?
No matter where you are on Earth, gravity causes all objects fall toward the center of Earth
If you are on a ship approaching a land mass, you see the tops of the tallest buildings first and the ground level last.

4. Other fun Earth facts: Diameter: 12,756 Km Circumference 40,075 Km
Mass: 598,000,000,000,000,000,000,000 Kg
Avg. Distance to Sun: 149,600,000 Km
Avg. Distance to Moon: 384,400 Km
Period of rotation: 23hr, 56 min, 4 sec (sidereal day)
Rotation: 24 hr 4 sec (solar day)
Period of revolution: 365 ¼ days

5. Earth’s magnetic field
The outer core of the Earth spins at a different speed than the outer layers; this causes a magnetic field with North and South magnetic poles
The magnetic poles are not static and move periodically since Earth rotates!
The magnetic poles deflect the solar wind, a stream of harmful electromagnetic particles ejected by the Sun.

6. The magnetic poles

7. Earth as a magnet

8. Magnetic poles deflecting the solar wind

9. Earth’s magnetic field
Some of these E.M. particles are pulled into the Earth’s magnetic poles
When this occurs, their energy can cause the particles in the atmosphere to glow
This phenomenon is called the Aurora Borealis (or Aurora Australis in the Southern Hemisphere)

10. Aurora

14. Earth orbits the Sun
Just like the orbits of all of the planets, moons, and comets, the Earth’s orbit is an ellipse.
Of the three other terrestrial (rocky surface) planets, Venus’s atmosphere is the most like Earth, but conditions on Mars are most like Earth
Venus is considered to be Earth’s twin due to its size!

16. Time and Seasons
Chapter 7, Section 2

17. Measuring time on Earth
The Earth makes one rotation in apx. 24 hours.
This spinning causes the Sun to appear to move across the sky from east to west.
If the Earth spins 360° every 24 hours then it spins 15° every hour (hence time zones).
Time zones are modified to fit cities, regions, or even countries.

18. Time Zones

19. The International Date Line is located at 180° longitude (in the middle of the Pacific)
The Earth makes one revolution around the Sun every days
The Earth’s orbit around the Sun is in an ellipse (an elongated circular path)

20. Why do seasons change?
The seasons are not caused by how close we are to the Sun!!!!
The seasons are caused by the axis, or tilt, of the Earth on its axis
The tilt of the axis is 23.5°
During our summer, the Northern Hemisphere gets more direct sunlight and more hours of it than the Southern Hemisphere does.
During our winter, the Northern Hemisphere gets less direct sunlight and less hours of it than the Southern Hemisphere does.

22. Intensity during the year

23. The Sun’s intensity varies on your latitude

24. Length of Day

25. At only two times during the year, all places on Earth have 12 hours of daylight and 12 hours of darkness.
They are called the equinox and occur on apx. March 21st and September 22nd.
On apx. June 21st, the summer solstice occurs. It is the day with the most hours of sunlight in the Northern Hemisphere and the day with the least hours of sunlight in the Southern Hemisphere.
On this day, the sun can be seen directly overhead at the Tropic of Cancer.

26. The opposite of the summer solstice is the winter solstice
The opposite of the summer solstice is the winter solstice. It is the day with the most hours of sunlight in the Southern Hemisphere and the day with the least hours of sunlight in the Northern Hemisphere.
On this day, the sun can be seen directly overhead at the Tropic of Capricorn.

27. Earth’s Moon
Chapter 7, Section 3

28. Movement of the Moon
The Moon revolves around the Earth every 27.3 days.
The Moon rotates (27.3 days) at the same speed that it revolves! So, the same side of the Moon always faces the Earth.
How Does the Moon affect gravity?
All objects that have mass have gravity. The Moon’s gravity also pulls on the Earth and all objects on Earth, causing ocean tides. The sun’s gravity also pulls on the tides too!

31. Moonlight
The Moon shines because it reflects sunlight off of its surface
Just like half of the Earth experiences day while the other half is night, so does the Moon.
Moon phases are the changing appearances of the Moon as seen from Earth. The phase you see depends on the relative positions of the Sun, Earth, and Moon.

33. Random Moon Phase Facts
It takes the moon 29.5 days to complete the phases.
Two full moons in one calendar month is called a blue moon.
Technically, each moon phase only lasts an instant…..but to our eyes, it looks the same for 3 ½ days!
Waxing phase: right side is reflecting light and continues to reflect more each night.
Waning phase: left side is reflecting light and reflects less light each night.

38. Eclipses There are two types of eclipses:
Solar eclipse – when the Moon casts a shadow onto the Earth
Lunar eclipse – when the Earth casts a shadow onto the Moon
Eclipse terms
Umbra- where the sunlight is totally blocked
Penumbra – where the sun is partially blocked

47. Upcoming Lunar Eclipses
2012 Nov 28Penumbral Europe, e Africa, Asia, Aus., Pacific, N.A.
2013 Apr 25Partial h27mEurope, Africa, Asia, Aus.
2013 May 25Penumbral Americas, Africa
2013 Oct 18Penumbral Americas, Europe, Africa, Asia
2014 Apr 15Total h35m 01h18mAus., Pacific, Americas
2014 Oct 08Total h20m 00h59mAsia, Aus., Pacific, Americas
2015 Apr 04Total h29m 00h05mAsia, Aus., Pacific, Americas

48. The Moon’s Surface
The moon has no atmosphere to burn up meteors and no weather to cover up scars left by meteors.
When the Moon was still cooling, meteors slammed into the Moon and broke through the crust causing lava to fill the craters causing dark-colored flat regions known as Maria.
Impacts on the Moon throughout its history caused a layer of rock and dust on its surface known as regolith.

49. Life in the Solar System (skip this section)

50. Lunar
Crater

51. Far Side of the Moon

52. The Moon’s interior
The Moon has a very thick Mantle and a small liquid iron core.
Exploring the Moon
In the 1960s, the U.S. Apollo Missions sent 24 astronauts to the Moon with 12 of them walking on its surface.
In the 1970s, the U.S. Clementine spacecraft orbited the Moon taking pictures to map the surface.
In 1998, the U.S. Lunar Prospector spacecraft took even more detailed images of the surface of the Moon.

54. Origin of the Moon
The generally accepted theory of how the Moon was formed is called the Giant Impact Theory.
The G.I.T. states that while the Earth was still cooling, a Mars-sized asteroid slammed into Earth causing a wad of material to eject out the other side of Earth. This material reformed into what is now the Moon.
The G.I.T. also explains how the Earth got it’s iron core and water.

55. Pick up your clicker and turn it on.
Let’s Review!
Pick up your clicker and turn it on.

56. A lunar eclipse occurs when the Earth’s umbra blocks the moon.
True
False

57. A solar eclipse occurs during a new moon phase.
True
False

58. Regolith on the moon are the dark, flat regions made of dried lava beds.
True
False

59. Many meteors were able to strike the moon’s surface since it does not have an atmosphere.
True
False

60. If you are in the penumbra during a solar eclipse, all of the sun will be blocked my the moon (total eclipse).
True
False

61. The Giant Impact Theory explains how the solar system was formed.
True
False

62. A partial eclipse occurs when you are in the object’s umbra.
True
False