1. Our Solar System & Scale
Grade 6
Image Credit: Slyavula Education

2. Content Topics
Scale of our Solar System in relation to our Milky Way Galaxy and the Observable Universe
Objects contained in our Solar System
Planet data and scale comparisons
Developing a scale

3. Our Solar System
Source: Solar System Videos

4. Our Milky Way Galaxy Video by ESA
Video by ESA

5. Our Location in the Universe

6. Our Place in the Solar System
We live on planet Earth
3rd Planet
Diameter = 7,917 miles (0.043 light seconds)
One planet in the Solar System
Diameter = 3.74 light years

7. Our Location in Space In the Milky Way Galaxy Part of the Local Group
1012 stars
Diameter = 100,000 light years
Part of the Local Group
Cluster of galaxies
Diameter = 10,000,000 light years

8. Our spot in the Visible Universe
Within the Virgo Supercluster
Cluster of galaxy clusters
Diameter = 110,000,000 light years
One tiny spot in our visible Universe
What we can currently see
“Diameter” = 14 Billion LY

9. Visible Universe
Image Credit: An Atlas of the Universe

10. Within one Universe Expanded Universe Diameter 93 Billion LY

11. Practice
Model the scale of our solar system in a sketch of the visible universe.
Our solar system would be a tiny dot on this page that would not be visible to the naked eye.
Compare the size (diameter) of our Solar System (3.74 LY) to the size (diameter) of our Milky Way Galaxy (100,000 LY).
100,000 = 26,738 The Milky Way Galaxy is 26,738 times
bigger in diameter!

12. (only one side of the solar system is shown)
More Practice
If the Solar system is 3.74 light years across, what is the distance shown in the image below? How do you know? ½(3.74) = 1.87 LY
(only one side of the solar system is shown)
Image Credit: astromonytrek.com

13. What is contained within our solar system?
Our solar system is centered on the Sun.
Planets orbit the Sun.
Moons orbit the planets.
Dwarf planets orbit the Sun.
Asteroids and Comets orbit the Sun.

14. Practice
What do you think the numbers are? How many of each object are contained in our solar system?
How do the sizes of these objects compare? Rank order them.
1st Stars (1 star)
2nd Planets (8 planets)
3rd Moons (100’s)
4th Asteroids (10,000’s)
5th Comets (Millions or Billions)

15. Our Sun
Image Credit: NASA

16. Sun Scale Diameter = 1,391,400 km (864,761 miles)
109 Earths would fit across the diameter of the Sun
1,300,000 Earths would fit inside of the Sun

17. Our 8 Planets & Pluto
Image Credit: NASA

18. Terrestrial Planets Which planets are comparable in size?
Earth and Venus
What fraction of Mar’s diameter is covered by the Valles Marineris?
about 2/3rds
Image Credit: Space.com

19. Terrestrial Planet Layers
Which planets have similar size layers?
Venus and Earth have similar thickness mantles.
Image Credit: Wikimedia commons

20. Practice
The Earth has a radius of 6,378 kilometers (3,963 miles). Earth’s mantle is 2,900 kilometers thick. What fraction of the Earth is mantle?
2,900 = 1.0 The mantle is approximately half the
6, thickness of Earth

21. Jovian Planets
Based on the image, how much larger are Jupiter and Saturn as compared to Uranus and Neptune?
Jupiter & Saturn are about 6 times larger than Uranus & Neptune
Image Credit: NASA

22. Jupiter’s Spot
Jupiter’s Great Red Spot is the longest lived weather disturbance in the solar system.
How many Earth’s would fit into Jupiter’s red spot?
3-4 Earths
Video & Image by NASA

23. Sizes of Planets Planet Name Planet Diameter Mercury 4,878 3,031 Venus
(kilometers)
(Miles)
Mercury
4,878
3,031
Venus
12,104
7,521
Earth
12,756
7,927
Mars
6,792
4,221
Jupiter
142,974
88,589
Saturn
120,536
74,914
Uranus
51,118
31,770
Neptune
49,528
30,782

24. Practice
Name two different ways to compare sizes of planets in our solar system.
Radius of planet
Diameter of planet
Orbital radius
Thickness of comparable layers

25. Moons
One of Saturn’s Moons
Moon
Phobos
Titan
Image Credit: NASA

26. Earth and Jupiter Earth has one Moon.
Jupiter has 68 moons, the largest is Ganymede.
How could we use data to compare scale sizes?
Compare in a ratio (set-up a fraction)
Subtraction
Scale sketch
Earth
Radius
Moon
Jupiter
Ganymede
6,371 km
1,738
71,492 km
2,631 km

27. Hubble Space Telescope
Dwarf Planets
Pluto is a Dwarf Planet
Dwarf planets are defined as objects that are similar to planets but do not meet all planet criteria.
Hubble Space Telescope
NASA

28. Dwarf Planet Pluto
New Horizons Image, NASA

29. Asteroids
Smaller than planets
Rocky
Image Credit: NASA

30. Comets Smaller than planets Icey Comet Halley's Nucleus
APOD 2010 January 4

31. Image Credit: NASA

32. Where are objects located in our Solar System?
The General Order is:
Sun, Mercury, Venus, Earth, Mars, Main Asteroid Belt (asteroids), Jupiter, Saturn, Uranus, Neptune, Pluto, Kuiper Belt (Plutinos and comets), and the Oort Cloud (comets)

33. Orbital Radius Planet Orbital Radius
The planets in our solar system orbit in ellipses that are nearly a circle.
How do the scales of planet separation compare for Terrestrial planets versus Jovian planets? How did you determine this?
Planet
Orbital Radius
Mercury
58 Million km
Venus
108 Million km
Earth
150 Million km
Mars
228 Million km
Jupiter
779 Million km
Saturn
1434 Million km
Uranus
2873 Million km
Neptune
4495 Million km

34. Other Stars have Orbiting Planets too!
HR 8799 harbors four super-Jupiters orbiting with periods that range from decades to centuries. Motion interpolate was used on 7 images of HR 8799 taken from the Keck Telescope over 7 years to create this image.
Movie Credit: Jason Wang and Christian Marois

35. Practice
The planet’s in HR 8799 are called super Jupiters. What do you think that means? Based on the scale properties of our solar system, what is a super Jupiter?
A Super Jupiter is a planet that is 2 or more times bigger in size than Jupiter.
Which planets in HR 8799 would have the longer orbital periods? How do you know?
The planets orbiting farthest from the star
Can observe them taking longer to orbit
We know it takes longer for planets in our solar system to orbit if they are far from the Sun

36. How is a scale determined?
Scale is based on factors or fractions.
10 times bigger than the actual size
1/4th the actual size
A scale model can be numbers, a drawing, or something you build.

37. One water molecule or Our Solar System
Scale
Scale models are used to see object properties that are very small or very big.
One water molecule or Our Solar System
0.275 nanometers
150 Million km
Image Credit: wordpress.com & NASA

38. Practice
If you wanted to fit a scale model of the solar system into your classroom, or outside on the playground, what scale would you use? How would you make it fit?
Average Sun-Mercury distance is 58 million km
Average Sun-Neptune distance is 4,495 million km
Average Sun-Oort Cloud distance is 750,038 million km
An easy first step would be to drop the million.
Another step could be to divide each by 58.
Then each scaled km could be equal to 1 step.
58 million km = 1 step
4495 million km = 77.5 steps
740,038 million km = 12,932 steps