Astronomy Topic: Solar System

1. Astronomy Topic: Solar System Definition: All space and objects within the Sun’s gravitational influence. (sun is sol, helios)

2. Topic 1: Our Star: the sun The Sun is the largest object in our solar system and accounts for about 99% of the solar system’s mass. The mass of the Sun influences the motions of planets and other objects in the solar system.

3. More Sun Stats; • Mass: 333,000 times greater than Earth; ~ 2.0 x 1030 kg • Composition: • 73% hydrogen • 25% Helium • 2% ‘other’ (oxygen, carbon, etc.) • Surface Temp: ~ 5800 K

4. Rotation: • 27 Days • We rotate in 1 day! • Diameter: • 1,392,000 km • That’s 109 times greater than Earth!

5. 3. Sunspots • Sunspots appear as dark areas on the surface of the Sun. • The spots are about 3000ocooler than the rest of the surface of the Sun!

6. c. A sunspot can be as large as 100,000 km in diameter. d. They follow an 11 year cycle and coincide with the Sun’s magnetic field reversals. http://solarscience.msfc.nasa.gov/SunspotCycle.shtml

7. Sun’s layers, from inside out: • Core • Site of fusion • Radiative Zone • Converts energy from fusion reaction to radiation • Convective Zone • Convection currents carry energy to surface • Photosphere • Emits most light radiation

8. Chromosphere: Only visible during a solar eclipse • Corona: Outmost layer; also only visible during a solar eclipse. • Sunspots: Cooler areas on the Sun’s surface • Solar Flare: A violent eruption of particles and radiation. • Prominence: An arc of gas ejected from the chromosphere; may exceed temperatures of 50,000K

9. 4. Stars like our star, the Sun, are typical main sequence stars. • It is not very large or hot. • When it becomes old (uses up its hydrogen) it will expand and become a Red Giant. • http://sohowww.nascom.nasa.gov • Age: 4.6 billion years old • Red Giant stage in 5 billion years. • It will nova and become a white dwarf.

10. 5. Stars: change hydrogen into helium during thermonuclear fusion in the core.

11. Topic 2. Measuring Distances and Energy in Space: • A.Lightyear is the distance light travels in a year. • Speed of light: 186, 000 miles/second • (670, 000, 000 miles/hr) • Lightyear : 10 trillion km, (or about 6 trillion miles )

12. d. Electromagnetic Spectrum: • 1. energy given off in transverse waves. • P. 14 ESRT

13. 2. All EME travels at the speed of light. • Longer wavelengths = lower energy have low frequency • Shorter wavelengths = more energy • have higher frequency

14. 3. Our star (sun) gives off primarily visible light has a continuous spectrum of VISIBLE LIGHT • Sun also gives off UV, infrared, and other wavelengths

15. 5. And around the sun…. • The 8 planets: planets are large, non-luminous rotating bodies that orbit a star.

16. The Solar Wind http://solarscience.msfc.nasa.gov/SolarWind.shtml

17. The solar wind streams off of the Sun in all directions at speeds of about 400 km/s (about 1 million miles per hour). The source of the solar wind is the Sun's hot corona. The temperature of the corona is so high that the Sun's gravity cannot hold on to it. http://solarscience.msfc.nasa.gov/SolarWind.shtml

18. Our 4 inner planets are rocky, small and dense. • Mercury and Mars have almost no atmosphere. • Venus is the ‘greenhouse’ planet.

19. Earth is the ‘blue’ planet with water in all 3 states of matter.

20. The asteroid belt has thousands of space rocks that orbit between Mars and Jupiter.

21. The 4 gas giants are found past asteroid belt. They are large, heavy, high in hydrogen and are low density. (jovian planets)

23. Kuiper Belt: contains many comets and the dwarf planets. • Comets are made of dirt and ice and ‘ignite’ when near the sun.

24. 7. Oort Cloud: theoretical farthest part of our solar system. Almost a lightyear out. https://solarsystem.nasa.gov/multimedia/display.cfm?Category=Planets&IM_ID=10195