1. Part One: Earth’s Place in Space Original PowerPoint Presentation is from the Gaston County Schools Secondary Science Website
Earth rotates and revolves around the Sun, even though it appears as though the Sun is moving! The Sun is the force which keeps our solar system together!
Rotation – spinning of Earth on its axis (23 degrees), which occurs once every 24 hours.
Earth moves around the Sun in a regular, curved path called an orbit
It takes about one year for Earth’s revolution around the Sun
We have leap years because our planet rotates exactly times in one revolution. So we have leap years to make up for that extra time!
SEASONS occur due to Earth’s tilted axis and its revolution around the Sun

2. TERMS TO KNOW….
Rotation: When an object spins on its axis (Think of a basketball spinning on a finger)
Revolution: When an object travels around another object
Orbit: The path that an object takes as it revolves around another
A Day on Earth

3. The Seasons
Change of seasons is a result of the tilt of the Earth’s rotation axis (23 degree slant) with respect to the plane of the ecliptic.
Sun, moon, planets run along the ecliptic (their paths)
We experience summer, when we tilt towards the sun.
We experience winter, when we tilt away from the sun.
Equinoxes: day and night of equal length
Accounts for the N-S motion of the sun on the celestial sphere

5. Motion of the Moon
Moon shines not by its own light but by reflected light of Sun
Moon revolves around the Earth
Moon’s period of rotation = 27.3 days
Period of revolution =27.3 days
The Tides of the oceans are caused by the moon’s pull on Earth
The Moon’s changing shapes are known as phases
Planets also shine by reflected light!

6. Phases of the Moon (THE LUNAR CYCLE) Caused by the position of the Earth, the Moon, and the Sun new to full = waxing full to new = waning

8. …and the phases…with Oreos! Copy this into your notes

9. Eclipses
One celestial object hidden by other or in the shadow of another
Solar eclipse: sun hidden by the Moon, as Moon is between the Sun and Earth and the Moon’s shadow falls on Earth
Lunar eclipse: Earth is between the Moon and the Sun and Earth’s shadow falls on the Moon
Most spectacular because moon and sun appear to be the same size from earth

10. Solar Eclipses Umbra – region of total shadow
Penumbra – region of partial shadow
Totality lasts only a few minutes!

11. Solar
Thin outer atmosphere, usually swamped by other light and hence invisible

12. Lunar Eclipses Moon moves into earth’s shadow…
Moon appears reddish due to light bent by Earth’s atmosphere
Aristotle argues earth is round based on shape of its shadow on the moon

13. Part One Review
What is the gravitational force that keeps our solar system together? Explain.
How are rotation, revolution, and orbit different?
Explain how the seasons occur. When do we experience summer and winter?
Explain why we have leap years.
How do we see the moon? List the phases of the moon beginning with a new moon.
What causes the tides of the earth?
What are eclipses? Identify and describe the differences between the two we discussed.

14. PART TWO: OUR SOLAR SYSTEM
THE MILKY WAY

15. Our Solar System
Earth orbits the Sun as the solar system revolves within the Milky Way, which is among billions of galaxies that make up the universe

16. Our Solar System is filled with eight major planets, the Sun, and other objects that orbit the Sun
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto (not classified as a planet any longer!)

17. THE SUN

18. The Sun The Sun is one of one-hundred billion stars in our galaxy.
It is the brightest object in the sky.
The sun is by far the largest object in our solar system.
It is the sun’s gravitational pull which holds our planets in order.

19. Inner Planets Solid, with minerals similar to those on Earth
Include Mercury, Venus, Earth, and Mars

20. MERCURY

21. Mercury
Mercury is the closest planet to the sun and is the smallest planet now that Pluto is deemed a “dwarf planet”
There is little to no atmosphere, resulting in extremes of temperature; can reach 430 degrees Celsius during the day and drop to –180 degrees Celsius at night!

22. VENUS

23. Venus Venus is the third brightest object in the sky.
It is the second closest planet from the sun and is the sixth largest.
Heavy cloud layer; clouds trap solar energy, making the planet extremely hot ~ 470 degrees Celsius!
Considered to be Earth’s twin because it’s similar in size.

24. EARTH

25. Earth Earth is the third planet from the sun and is the fifth largest.
This planet is the densest major body in our solar system.
The Earth’s atmosphere protects its life from the harmful rays of the sun.
Life on Earth is possible because of water availability and the stability of temperatures.

26. MARS

27. Mars
Mars is the fourth planet from the sun and is the seventh largest.
The first space craft to visit Mars was the Mariner 4 in 1965.
Has seasons and polar ice caps; may have water shaping its surface
Red due to rocks containing iron oxide
Two small moons

28. Asteroid Belt
Separates the inner (rocky) and outer (gas giants with lots of moons and rings) planets
It is located between the planets of Mars and Jupiter
Pieces of rock made of minerals similar to those that formed the rocky planets and moon
Jupiter’s huge gravitational force might have prevented a small planet from forming in the area of the asteroid belt

29. JUPITER

30. Jupiter
Jupiter is the fifth planet from the sun and is by far the largest planet.
Jupiter is the fourth brightest object in the sky.
28 moons; Giant Red Spot is a giant storm on the planet’s surface

31. SATURN

32. Saturn
Saturn is the sixth planet from the sun and is the second largest.
Saturn is the least dense of all the planets because it is mostly composed of gases (hydrogen and helium)
Has 30 moons; several broad rings of ice and dust.

33. URANUS

34. Uranus
Uranus is the seventh planet from the sun and the third largest.
Uranus has only been visited one time, by the Voyager 2 in 1986.
Axis makes the planet spin nearly sideways; has rings and 21 moons

35. NEPTUNE

36. Neptune
Neptune is the eighth planet from the sun and is the fourth largest.
Neptune has 8 moons.
Atmosphere is composed of hydrogen, helium, and methane (make planet blue)

37. PLUTO

38. Pluto
Pluto is the farthest object from the sun and is by far the smallest

39. All planets move in same plane except Pluto
all planets orbit in same direction (ccw as seen from above the north pole)
all orbits lie nearly in a single plane (Mercury (7deg) and Pluto (17deg) being most notable exceptions)
inner planets are small, dense, rocky (Terrestrial); outer planets are large, gaseous, low density (Jovian)
density = mass/volume
inner planets close together, outer planets further apart

40. Is Pluto a planet? Orbit too weird Too small
Today Pluto may not be classified as a planet.

41. Comets
Large body of frozen ice and rock that travels toward the center of the solar system
As a comet approaches the Sun, radiation vaporizes some of the material; solar winds blow vaporized gas and dust away from the comet, forming what appears from Earth as a bright, glowing tail

42. Meteorites Fragments of space material that land on Earth’s surface
Pieces may be iron, rock, or both
Age (4.5 billion years) provides a clue to the Solar System’s age

43. Stars About 5000 stars visible with naked eye
About 3500 of them from the northern hemisphere
Stars that appear to be close are grouped together into constellations
Officially 88 constellations
Names range from
mythological (Perseus, Cassiopeia)
technical (Air Pump, Compass)

44. Lives of Stars A star has a life that depends on its size
Stars begin their lives as huge clouds of gas and dust
Force of gravity causes dust and gases to move closer together
Temperatures within the cloud begin to rise
Star is formed when this cloud gets so dense and hot that the atoms within it merge (fusion)

45. Galaxies Group of stars, gas, and dust held together by gravity
Earth is in a spiral galaxy called the Milky Way
100 billion galaxies might exist ~ all these galaxies with all their stars make up the UNIVERSE!