The Sun Section 2

1. Chapter 20 – The Solar System The SunSection 2

2. Image From: http://www.oglethorpe.edu/faculty/~m_rulison/Astronomy/Chap%2016/chapter_16_lecture_notes.htm

3. The Sun The Sun’s Interior • The energy from the sun comes from nuclear fusion. • Nuclear fusion happens when hydrogen atoms have so much energy from high temperatures and pressures, they bond together to form helium atoms. • LOTS of energy is released during nuclear fusion.

4. The Sun Animation of Nuclear Fusion Image From: atomicarchive.com

5. The Sun The Sun’s Interior • The temperature inside the core of the sun reaches about 15 million ºC. • There is enough hydrogen fuel to last 10 billion years. Currently, the sun is only about 5 billion years old.

6. The Sun The Sun’s Interior • There are three layers of the sun’s interior. • The Core: • Contains 2% of the volume of the sun but almost ½ of the sun’s mass. • Almost all of the fusion in the sun takes place in the core. • Radiative Zone: • Energy travels through this zone by radiation. • Convection Zone: • Energy travels through this zone by convection.

7. The Sun Image From:

8. The Sun The Core Radiation Zone Convection Zone Image From: http://www.physics.hku.hk/~nature/CD/regular_e/lectures/chap11.html

9. The Sun The Sun’s Atmos-phere • There are three layers to the sun’s atmosphere. • Photosphere (inner layer): • the sphere that makes light • Chromosphere (middle layer): • the color sphere – reddish glow around the photosphere • Corona (outer layer) • looks like a white halo around the sun only visible during solar eclipses • sends out the solar wind (streams of electrically charged particles

10. The Sun The Sun’s Atmos-phere • the Earth’s magnetic field blocks the solar wind from the sun • the solar wind enters the Earth’s atmosphere near the poles, interacts with gas in our atmosphere, and causes auroras

11. The Sun The Core Radiation Zone Convection Zone Photosphere Chromosphere Corona Image From: http://www.physics.hku.hk/~nature/CD/regular_e/lectures/chap11.html

12. The Sun Features on the Sun • Sunspots: • look like small dark areas (usually in pairs or groups) in the gas on the sun • although they look small, they can actually be as large as the Earth! • a sunspot is an area of cooler gas that doesn’t give off as much light • the number of sunspots varies over 10-11 years • the number of sunspots may be linked to temperature and climate change on Earth

13. The Sun Features on the Sun • Prominences: • reddish loops of gas that link different parts of sunspot regions • if the sunspots are near the surface of the sun, the prominence may stick out over the edge of the sun

14. The Sun Features on the Sun • Solar Flares: • explosions from the sun out into space • caused by sunspot regions suddenly connecting which releases lots of energy • increases the solar wind from the corona • can create magnetic storms on Earth because of the increase in charged particles

15. The Sun Image From: ircamera.as.arizona.edu

16. The Sun Image From: fusedweb.llnl.gov

17. The Sun Image From: visual.merriam-webster.com

18. The Sun An illustration of the structure of the Sun: 1. Core2. Radiative zone3. Convective zone4. Photosphere5. Chromosphere6. Corona7. Sunspot8. Granules9. Prominence Image From: nastro.org.uk

19. The Sun SUN FACTS • Volume: • Mass: • Density: • Composition: • Rotation Period at Equator: • Rotation Period at the Poles: • Average Distance from Earth: 1,300,00 Earths or 1.412 x 1018 km3 or 2.7403 x 1017 mi3 332,900 x Earth or 4.38 x 1030 lbs or 1.989 x 1030 kg 0.255 that of Earth or 1.409 g/cm3 0.255 that of Earth or 1.409 g/cm3 92.1% Hydrogen, 7.8%Helium 26.8 days 36 days

20. The Sun National Geographic Interactive of the Sun More Sun and Star Virtual Sun