The Inner Solar System

1. The Inner Solar System • The four inner planets are all relatively small and dense, and have rocky surfaces. • The terrestrial planets are planets similar in structure to Earth. • Mercury, Venus, Earth, and Mars are called the terrestrial planets.

2. The Sun • The sun’s energy is produced in its central region by the fusion of hydrogen nuclei into helium nuclei. • The sun remains stable because the inward pull of gravity balances the outward push of thermal pressure from nuclear fusion. Nuclear_Fusion_Joins_AtomsNuclear_Fusion_Creates_New_Elements

3. The Sun’s Interior • The sun’s interior consists of the core, the radiation zone, and the convection zone. • Core – is the sun’s central region, where nuclear fusion occurs. • Radiation Zone – is a region of compressed gas. Energy is transferred by the absorption and reradiation of electromagnetic waves. • Convection Zone – The outer layer of the sun. energy is transferred outwardly by convection currents.

4. The Sun’s Atmosphere • Photosphere – the innermost layer of the sun’s atmosphere. It is the visible surface. • The photosphere is not a solid, but it is considered the surface. • Astronomers can’t see through the photosphere. • The_Photosphere_and_the_Solar_Wind

5. The Sun’s Atmosphere • Chromosphere – is the middle layer of the sun’s atmosphere. • At high temperatures, hydrogen emits a reddish color. • Chromosphere means “sphere of color”

6. Corona • The corona is the outermost layer of the sun’s atmosphere. • The gases are thin at this layer • The chromosphere and corona can only be seen during solar eclipses.

7. Stages of Solar Eclipse • The corona can only be seen from Earth during a total solar eclipse or when viewed with a special telescope.

8. Features of the Sun’s Atmosphere • Sunspots – small dark regions on the sun’s surface. • Sunspots are areas of gas in the photosphere that are cooler than the surrounding gases. • Sunspots give off less energy

9. Other Features • Prominences – occur near sunspots. They are huge loops of gas that erupts. • Solar Flares – the sun’s surface erupts hurling charged particles into space

10. Review Concepts • What is the source of the sun’s energy? • Nuclear fusion in the sun’s core. • What two forces in the sun interact to produce a stable structure? • Gravity and the thermal pressure from fusion. • List the layers of the sun’s interior from the center outward and describe each one. • Core: central region where fusion takes place; Radiation zone: middle layer, energy is transferred by radiation; convection zone: outer layer, energy is transferred by convection. • List the layers of the sun’s atmosphere • Photosphere, chromosphere, corona • List three features that exist on the sun’s surface. • Sunspots, Prominences, and Solar flares

11. Debbie’s sun Exploring_Space__The_Universe Video_Quiz__The_Sun__Our_Star_Attraction

12. Why they are called the “Inner Planets” The innerplanets are the four planets that lie between the Sun and the asteroid belt. Mars Earth Venus The planets that are located after the asteroid belt are called the outerplanets. Mercury That makes sense, doesn’t it?

13. Mercury • Mercury is the smallest of the terrestrial planets and the closest planet to the sun. • Mercury is a dense planet with a very large iron core. • Mercury is geologically dead. • There is no mantle convection within the planet and little erosion on its surface.

14. Mercury • Distance from the sun: 57,909,175 km • Origin of Name: the Roman messenger of the gods • Size (in diameter): 4,880 km • Interesting Fact: The temperature can range from -200 C to over 430 C!

15. Mercury • Mercury is solid and is covered with craters. • Mercury has almost no atmosphere. • Mercury is the smallest planet. • .055 x Earth • -173 to 427° C • 70% metal, 30% silicates • Mariner 10 & Messenger space probes

16. Venus • Distance from the Sun: 108,208,930 km • Origin of Name: The Roman goddess of love and beauty • Size (in diameter): 12,103.6 km • Interesting Fact: It is sometimes known as Earth’s “sister planet” because of their similar size, mass, volume, and density!

17. Venus • Venus’s thick atmosphere is composed mostly of carbon dioxide, which traps heat and raises the planet’s temperature. • Venus’s atmosphere contains droplets of sulfuric acid. • Average surface temperature 460 degrees.

18. Venus • Venus takes 8 months to turn on it’s axis & rotates counter-clockwise • The surface is rocky and very hot. • .815 x size Earth • Average temp of 462°C • The atmosphere (CO2)completely hides the surface and traps the heat. • 92x greater pressure than Earth (same as deep ocean) • More than 20 space probes from USA & USSR

19. Earth • Distance from the Sun: 149,597,890 km • Origin of Name: Old English and Germanic • Size (in diameter): 12,756.3 km • Interesting Fact: The Earth is not perfectly round, but actually pear-shaped!

20. Earth • Earth is the fifth largest planet and the third from the sun. • Composed of Iron & Nickel • Liquid covers 71 percent of the Earth’s surface. • The Earth has one moon. • Atmosphere is primarily nitrogen & oxygen • 12,756 km in diameter • Average temp of 61°F or 16°C

21. Mars • Distance from the Sun: 227,936,640 km • Origin of Name: the Roman god of war • Size (in diameter): 6,794 km • Interesting Fact: The month of March got its name from Mars!

22. Mars • Mars is the most Earthlike of all of the planets. The weathering of iron rock on its surface gives the planet a reddish color. This is why Mars is called the “Red Planet.”

23. Mars • Mars looks red because it has iron oxide (rust) • Mars has a thin atmosphere that contains mostly carbon dioxide. • Mars is .107 x size of Earth • Average temp is -86 to -5°C • 16 space probes

24. Moons of Mars Phobos Deimos Moons of Mars

25. Mars

27. Asteroids • Beyond Mars is a region of small, rocky bodies called asteroids that orbit the sun. • This region is referred as the asteroid belt • Scientist now hypothesize that asteroids are remnants of the early solar system that never came together to form a planet