1. Astronomy
Inner Planets

2. Objectives
Explain the difference between a planet’s period of rotation and period of revolution
Describe the difference between prograde and retrograde rotation
Describe the individual characteristics of Mercury, Venus, Earth and Mars
Identify the characteristics that make Earth suitable for life

3. Did You Know??? Venus is the only planet that rotates clockwise.
Source -

4. The Inner Planets
Terrestrial Planets – a smaller, planet made of rock.
The terrestrial planets are Mercury, Venus, Earth and Mars

5. The Inner Planets

6. The Inner Planets

7. Mercury

8. Mercury Mercury is the closest planet to the sun
During the Day the temperature gets up to 800 oF
At night the temperature drops to -279 oF
On Mercury you would only weight 38% of what you weight on
Earth
Mercury
Size
4,879 km
Moons
Rings
Symbol
Rotation (Day)
1,392 EH (59 days)
Revolution (Year)
88 ED

9. Mercury Mercury rotates on an axis of 0o
This means that Mercury has no seasons because every part of mercury sees the sun equally throughout the year

10. Mercury
These are actual pictures taken of Mercury from Mariner 10 in March 1974

11. Venus

12. Venus Venus is the second closest planet to the sun
Venus is the hottest planet because its thick atmosphere creates a strong greenhouse effect
The surface temperature on Venus is 867 oF
Mercury
Size
12,104 km
Moons
Rings
Symbol
Rotation (Day)
243 ED
Revolution (Year)
224 ED

13. Venus
These are actual pictures taken of Venus from Magellan in 1992

14. Mountains of Venus
The mountains on Venus are larger than any mountains on Earth.
The four major mountain ranges on Venus are: Maxwell, Frejya, Akna, and Danu Montes

15. Venus
These are actual pictures taken of Venus from Mariner 10 in February 1974

16. Venus Venus is the only planet that has a retrograde rotation
Prograde Rotation – The counterclock wise rotation of a planet
Retrograde Rotation – The clockwise rotation of a planet

17. Venus Venus rotates upside down on an angle of -3o
This means that not only does Venus also have no seasons like Mercury, it is upside down

18. Venus Rotation

19. Earth

20. Earth

21. Earth Earth is the 3rd planet from the sun
Earth is the only planet known for supporting life
Earth
Size
12,756 km
Moons 1
Rings
Symbol
Rotation (Day)
24 EH
Revolution (Year)
365 ED

22. Earth Earth’s axis is at an angle of 23.5o
This is what gives us our seasons

23. Mars

24. Mars

25. Mars Mars is the most studied planet in our solar system
Mars has a very thin atmosphere, because of this its temperatures range from -189 oF to 98 oF
In the past Mars was alive with volcanic activity, however those
volcanoes are now
extinct
Mars
Size
6,794 km
Moons 2
Rings
Symbol
Rotation (Day)
24 EH
Revolution (Year)
1 EY 322 ED

26. Mars Mar’s axis is at an angle of 25o
Mars seasons are a little longer than ours because its axis is titled just a little more

27. Mars
Mars has 2 moons: Phobos and Deimos

28. Mars Moons

29. Mars Moons

30. Mars
These are actual pictures taken of Mars from Viking 1 & 2

31. Mars
These are actual pictures taken of Mars from Pathfinder in 1997

32. From Earth to Mars

33. Mars
Because water previously existed on mars, it left many strange rock structures

34. Water on Mars
The rock structures on Mars show areas of erosion and deposition similar to those left by bodies of water on Earth
This leads scientists to believe mars was once a watery planet with a much thicker atmosphere
There is also a large polar icecaps on mars

35. Water evidence on Mars

36. Water on Mars

37. Polar Icecaps on Mars

38. Review Mercury is the 1st planet Venus is the 2nd planet
Temperatures on Mercury can range from 800oF to -279o F
Mercury has no seasons because it’s axis is vertical
Venus is the 2nd planet
Venus is the hottest planet
Venus has larger mountains than Earth
Venus is upside down on its axis and rotates backwards
Earth is the 3rd planet
Earth is the only planet to support life
Mars is the 4th planet
In the past, Mars was alive with volcanic activity and water flow