1. Earth in Space

2. Astronomy
The study of the moon, stars, and other objects in space = astronomy.
Ancient astronomers studies the stars and the movements of the sun and moon.
It was thought that the Earth was the center of the Universe and the moon and sun moved around us.
We now know the Sun is the center of our universe and the Earth and all other objects (planets, moons and stars) orbit around the sun.

3. Rotation
Earth has an imaginary line that runs from the north pole to the south pole – axis.
The Earth spins around this axis = rotation
1 complete spin takes 24 hours and creates a day/night cycle.
Rotational spin is from the west to the east
The sun appears to rise in the east and set in the west.
North
South

4. Revolution Earth revolves, Orbits, around the sun
1 revolution – 1 year or 365 ¼ days
February 29th, leap year, is added each 4th year to = 366 days
Earth’s orbit around sun is not a perfect circle but more oval (elliptical).
Winter’s distance from the sun is actually closer than summer’s distance.

5. Earth’s Seasons Earth is tilted on it’s axis at 23.5°
Seasons occur due to this tilt.
When the Northern Hemisphere is pointing toward the sun it is experiencing summer.
Southern Hemisphere = winter
When the Northern Hemisphere is pointing away from the sun it is experiencing winter.
Southern Hemisphere = summer

6. Earth’s Seasons

7. Earth’s Seasons - Northern Hemisphere -
Spring – March 21st
Vernal Equinox
Equal day and night
Sun is directly over the equator
Summer – June 21st
Summer Solstice
Longest amount of daylight hours
Sun is directly over the Tropic of Cancer
Fall – Sept 23rd
Autumnal Equinox
Winter – Dec. 22nd
Winter Solstice
Shortest amount of daylight hours
Sun is directly over the Tropic of Capricorn

8. The Moon Moon revolves around the earth Moon also rotates on its axis
Earth’s only satellite!
1 revolution – 1 month or 27.3 days
Moon also rotates on its axis
1 rotation = 27.3 days
Rotation = Revolutions
1 day = 1 year
Same side of the moon always faces the earth!

9. Moon’s Orbit
scssi.scetv.org/

10. Moon Phases
As the moon revolves around the earth the amount of lit surface, visible from earth, is always changing.
Waxing phases – lit surface is increasing
Light on the right!
Waxing Crescent
1st Quarter
Waxing Gibbous
Full Moon – full lit surface facing earth

11. Waxing Crescent
Light on the RIGHT

12. First Quarter Moon
Light on the RIGHT

13. Waxing Gibbous
Light on the RIGHT

14. Full Moon

15. Moon Phases Waning phases – lit surface is decreasing
Light on the left!
Waning Gibbous
3rd Quarter
Waning Crescent
New Moon – no lit surface facing earth

16. Waning Gibbous
Light on the LEFT!

17. 3rd Quarter Moon
Light on the LEFT!

18. Waning Crescent
Light on the LEFT!

19. New Moon

20. Moon’s Phases

21. Eclipses
On rare occasions during the moon’s revolution around the Earth, the moon or Earth completely blocks the sun from each other – Eclipse.
The moon’s orbit is tilted at 5° so it rarely goes directly between the Earth and sun.

22. Solar Eclipse Occurs during a New Moon
Moon is between the Earth and sun.
Moon’s shadow is cast onto the Earth.
Umbra – the smallest and darkest part of the moon’s shadow
Only people within the umbra experience a total solar eclipse.
Penumbra – largest part of the shadow outside the umbra that is not as dark.
People within the penumbra experience a partial solar eclipse.

24. Lunar Eclipse Occurs during a Full Moon.
The Earth is between the moon and sun.
Earth’s shadow is cast on the moon.
Can be seen anywhere on Earth that the moon is visible.
Greater chance of seeing a total lunar eclipse than a total solar eclipse.

26. Tides
The rise and fall of Earth’s water is controlled by the moon and its gravitational pull causing a daily cycle of tides.
As Earth rotates, the moon’s gravity pulls the water toward the point on Earth closest to the moon.
2 high tides daily – every 12 hours
2 low tides daily – every 12 hours
What is the time between a high and low tide?
6 hours

27. Tides The sun’s gravitational pull also affects Earth’s water.
Spring tides – higher than high tides
Sun, earth and moon are all aligned together
occur twice a month on full moon and new moon
Neap tides – tides with the least difference between high and low.
Sun, earth and moon are at right angles to each other.
occur twice a month 1st quarter and 3rd quarter
Tide Simulation

29. Spring Tides

30. Neap Tides