1. The Inner Planets

2. The Inner Planets to Scale
3,031 mi ,521 mi ,926 mi ,222 mi
5.4 g/cm g/cm g/cm g/cm^3

3. The Sun in the Solar System
Gravitational pull of the Sun causes planets and other objects in solar system to orbit the Sun.
More than 99% of all the mass in the solar system is in the Sun
Shape of orbit is an ellipse
Sun is not quite at the center of each orbit

4. The Inner Planets

5. Inner Solar System Terrestrial planets Mercury, Venus, Earth, Mars
closest to the Sun
Rocky crusts and dense mantles and cores
Atmosphere on terrestrial planets formed from gas
gravity pulls the gases in and keeps them near surface if planet’s gravity is strong enough

6. Inner Planet Similarities
All are a few thousand miles across
All are made of rock, with an iron core
All are dense (because made of rock)
Why do the inner planets share these similarities?

7. Mercury Orbits once every 88days Smooth plains and many craters
Parts covered with lava long ago, forming long, smooth plains
Long, high cliffs
Virtually no atmosphere

8. Mercury’s Surface
What do you see?

9. Venus Similar in size and density to Earth Nearest planet to Earth
Carbon Dioxide levels in the atmosphere cause the planet to be much hotter than Mercury, Earth, or Mars.
Has volcanoes and flat lava plains

10. Venus’ Surface Sent spacecraft to take pictures from the surface
Lasted 2 hr 7 min
Found out it was 865°F at the surface!
Why so hot?

11. Venus Through the Clouds
You look through the clouds – with RADAR!

12. Earth Only planet known to have liquid water
Only planet known to have life
What features of Earth allow it to sustain life?
Earth

13. Mars Wind causes weathering and erosion similar to Earth
Has two tiny moons
Atmosphere - mostly CO2; air pressure is about 1% of Earth’s
Fast winds cause gigantic dust storms

14. Martian Canyons Largest canyon – 3,000 miles long and 5 miles deep
Rocks shrink when they cool. Astronomers think Mars may have cooled quickly after its formation; how might this be used to explain the large canyon?

15. Comparing the Inner Planets
Mercury Statistics
Distance from sun 3.2 light-minutes
Period of rotation 58 days, 16 hours
Period of revolution 88 days
Diameter 4,879 km
Density 5.43 g/cm3
Surface temperature –173 to 427°C
Surface gravity 38% of Earth’s
Venus Statistics
Distance from sun 6.0 light-minutes
Period of rotation 243 days, (R)*
Period of revolution 224 days, 17 hours
Diameter 12,104 km
Density 5.24 g/cm3
Surface temperature 464°C
Surface gravity 91% of Earth’s
Earth Statistics
Distance from sun 8.3 light-minutes
Period of rotation 23 hours, 56 min
Period of revolution 365 days, 6 hrs
Diameter 12,756 km
Density 5.52 g/cm3
Surface temperature –13 to 37°C
Mars Statistics
Distance from sun 12.7 light-minutes
Period of rotation 24 hours, 37 minutes
Period of revolution 1 year, 322 days
Diameter 6,794 km
Density 3.93 g/cm3 / Gravity 38% of Earth’s
Surface temperature –123 to 37°C

16. Why do terrestrial planets have atmospheres
Why do terrestrial planets have atmospheres? gravity What planet is closest to Earth in size and mass? Venus The coldest terrestrial planet is Mars and the warmest terrestrial planet is Venus.

17. Venus’ atmosphere is very dense and causes the planet to be much hotter than all of the other planets. The Earth is the only body in the solar system that appears to be able to support life.

18. Earth’s Rotation Rotation is the spinning of the Earth on its axis.
The time for one rotation is 24 hours.
Basically one planetary day!
Click image to view Earth’s rotation.

19. Earth’s Revolution
A revolution occurs as the earth moves around the sun.
Time for one revolution = 365 1/4 days = 8,766 hours
Basically one planetary year!

20. Round One 1. The Earth spinning on its axis.
Rotation
Revolution
2. Going around a larger body.
Rotation
Revolution
Revolution
3. 24 hours or 1 day.
Round One
Rotation
Revolution
4. Causes the Earth’s seasons.
Rotation
Revolution
5. Creates a year.
Rotation
Revolution
6. The moon going around Earth.
Rotation
Revolution

21. Identify the motion being shown in each of these pictures
Identify the motion being shown in each of these pictures. Each team must write their answers for each figure in the form of a question.
Figure #1
Rotation
Revolution
Planet
Round Two
Figure #2
Earth
Rotation
Revolution