1. The Sun
Chapter 14.2

2. Standard
8.2.g. Students know the role of gravity in forming and maintaining the shapes of planets, stars and the solar system
8.4.b. Students know that the sun is one of many stars in the Milky Way galaxy and that stars may differ in size, temperatures, and color.

3. Introduction
The sun accounts of 99.8 percent of the solar system’s total mass.
The sun exerts a powerful gravitation force throughout the entire solar system,

4. Energy from the Sun ¾ of the sun’s mass is hydrogen Nuclear Fusion
The sun produces energy through nuclear fusion.
Nuclear Fusion: two atomic nuclei combine forming a larger more massive nucleus and releasing energy

5. Energy from the Sun

6. Energy from the Sun Core: the central region of the sun
The temperature within the core reaches about 15 million degrees Celcius
This energy reaches Earth as light and heat
Forces in Balance
Astronomers estimate that the sun will be stable for another 5 billion years or so

7. The Sun’s Interior
The sun’s interior consists of the core, the radiation zone, and the convection zone
The Core: 400,000 km, more than 30 times the Earth’s Diameter

8. The Sun’s Interior
The Radiation Zone: region of very tightly packed gas where energy is transferred mainly in the form of electromagnetic radiation
The Convection Zone: The outermost layer of the sun’s interior.

9. The Sun’s Atmosphere
The sun’s atmosphere includes the photosphere, the chromosphere, and the corona
The Photosphere: part of the sun that gives off visible light
Photos = light

10. The Sun’s Atmosphere The Chromosphere: The glow comes from this layer
Chroma = color
The Corona: Looks like a white halo around the sun
In Latin = Crown
Extends into space for millions of kilometers, and gradually thins into streams of electrically charges particles called the solar wind

11. The Corona

12. Features on the Sun Features on or just above the sun’s
surface include sunspots, prominences and
solar flares.
Sunspots: areas of gas on the sun’s surface that are cooler than the gases around them
Since the sunspots seems to change location, this means the sun rotates on its axis, like the Earth does.

13. Features on the Sun Prominences: huge, reddish loops of gas
Solar Flares: eruptions that happen on the sun
Solar Wind: can affect Earth’s magnetic field.