CHAPTER 24.3 THE SUN

Learning Targets

1. Describe the layers of the Sun2. Describe the surface features of

the Sun

The Sun

1. 99.8% of all matter in the solar system

2. Average star3. Fourth State of Matter – Plasma :

Made up of superheated gas with an electrical charge Hydrogen to Helium

Solar Layers

1. The sun has no surfacea) Layers and zones can be

detected but there are no clear lines

b) Like fire

Internal Structure of the Sun

1. Corea) 27,000,000°Cb) Nuclear fusion releases energy

2. Radiative zonea) Photons release energy moves away from

the core3. Convection zone

a) Hot particles rise and cooler particles sinki. Convection helps to create solar flares

and sunspots

The Outer Layers

1. Photospherea) Layer that we seeb) Radiates visible light

2. Chromospherea) Glows red & heated by photosphere

3. Coronaa) Outermost plasma layerb) Hottest layerc) Only visible when photosphere is

blocked

Surface Features

1. Sunspots - Loops of magnetic energy make the Sun cooler in places

a) Occur in 11-year cyclesb) Form solar flares when the loops

break2. Solar flares release energy and

particlesa) Solar windb) Produces aurora in Earth’s

thermosphere3. Solar prominence: plasma flows along

the loop from sunspot to sunspot