California Standards: 1a, e. The Sun California Standards: 1a, e.

Sun’s Energy The sun, and most other stars, gets its energy from the fusion of atoms within it core. Hydrogen is the main source of fuel for stars. Hydrogen is fused into helium at extremely high temperatures, such as 15,000,000o C.

Energy Source for the Stars Energy is produced by the fusion of hydrogen into helium in the core of the sun. This takes place at 10,000,000 degrees Kelvin or 10,000,000o K Other elements are created also such as calcium, iron, etc. Occurs when temperature and pressure are great enough.

Fusion of Hydrogen in the Sun E = mc2

Composition of the Sun Each star has its specific “signature”. Just as humans have finger prints, stars have specific signatures that are determined by a spectrograph or a graph which shows what gases or elements are found in that star.

Spectrograph for hydrogen against a stars spectrograph.

The Sun’s Interior The interior of the sun is divided into three sections. The core is where extremely high temperatures and pressures create the conditions for fusion. The radiative zone is where energy moves outward. The convection zone where energy is transferred to the sun atmosphere.

The Sun’s Atmosphere The photosphere is where much of the visible light given off by the sun originates. The temperature is about 6,000o C The dark spots of the photosphere are called sun spots whose temperature is a cool 3,800o C

The Sun’s Interior

Structure of the Sun A. _____________ B. _____________ D. ____________ E. ____________ F. ____________

Solar Activity The sun in nothing more than a ball of hot gases. The sun rotates every 27 days on average. Sunspots are cooler than the rest of the sun and have a cycle of 11 years.

Features of the Sun Sunspots are cool areas of the sun They are not permanent but can last for days before disappearing. Cycle over 11 year period

Photosphere Sun spots in the photosphere

Sunspots

Sunspot Activity

Sunspot activity, 11 year cycle

Solar Ejections Prominences are clouds of gases that form huge arches. Solar flares are a sudden outward eruption of electrically charged particles. Coronal Mass Ejections are particles that are thrown into space and cause geomagnetic storms on Earth.

Solar Prominences

Solar Flare Earth

Earth’s Magnetic Field Earth has a magnetic field caused by the movement of it’s iron-nickel core. This magnetic field protects Earth from radiation emitted from our sun. This magnetic field gives rise to auroras at the North and South poles.

Earth’s Magnetic Field

Coronal Mass Ejections (CMEs) CMEs are solar hurricanes that send out magnetic bubbles thousands of kilometers across filled with billion-ton plasma clouds at millions of kilometers per hour.

Coronal Mass Ejections

Coronal Mass Ejections Coronal mass ejections result in particles striking our magnetosphere surrounding the Earth. This results in geomagnetic storms which result in auroras that are called the Northern Lights.

Coronal Mass Ejections

Northern Lights or Aurora

All stars are not alike. 1. The sun is a small star 2. The sun is called a main sequence star. Meaning that it is just an average star in size and age. 3. There are much larger stars in the universe. 4. These larger stars are called supergiants.

How large is our Sun? supergiant

Current Solar Reseach National Aeronautic and Space Administration (NASA) launched a new satellite. The new satellite is called STEREO, Solar TErrestrial RElations Observatory which uses two satellites to observe the sun. For the first time these satellites provide a 3-D view of the sun.

STEREO satellites

Here Comes the Sun