The Sun and Our Earth The Structure of Our Sun The Energy of Our Sun The Activity of Our Sun The Affects of Our Sun on Earth

The Structure of the Sun

The Sun’s Interior The core at the center of the sun ionized gas extremely dense (10x denser than iron) electrons are stripped away from nuclei nuclear fusion occurs here

The Radiative Zone zone surrounding the core energy moves outward through this zone from the core in electromagnetic waves

Convective Zone surrounds the radiative zone energy produced in the core moves through this zone by convection hot gases carry energy to the sun’s surface.

The Sun’s Exterior or the Atmosphere of the Sun The Photosphere Made up of gases from the Convection Zone The energy given off is in the form of visible light The Chromosphere Glows with reddish light gases form narrow jets of hot gas that shoot outward and then fade away The Corona Huge region of gas = crown Not very dense Has a strong magnetic field

The Energy of Our Sun Composition: Gases that make up the sun are: Hydrogen – 90% Helium – 8% Gases create energy through nuclear fusion. Nuclear fusion: the process of combining the nuclei of small atoms to form more massive nuclei. A small amount of matter is destroyed or converted into energy.

Nuclear Fusion

Nuclear Fusion: Step 1: Two protons from hydrogen nuclei collide and fuse. The positive charge of one of the protons is neutralized as that proton emits a particle. That proton then becomes a neutron and now there is a proton-neutron pair. Step 2: Another proton combines with this proton-neutron pair to produce a nucleus made up of two protons and one neutron. Step 3: Two nuclei made up of two protons and one neutron collide and fuse. Two protons are released. The two protons and two neutrons fuse together to form a helium nucleus.

The Sun’s Magnetic Field Movement of the Convection Zone and the rotation of the sun produces magnetic fields on the sun.

Sunspots Solar Ejections Activity of the Sun Sunspots Solar Ejections

Sunspots

Sun spots The Cause: Magnetic fields causes the convection to slow in the convection zone. Slower convection causes a decrease in the amount of gas that is transferring energy from the core to the photosphere. Because less energy is transferred, some regions of the photosphere are cooler than the surrounding region

Sunspots Appearance These areas appear darker These areas will appear more grainier These areas are cooler These areas will have a stronger magnetic field

Sunspots The Sunspot Cycle Number and position of sunspots varies every 11 years. The cycle begins when the number is low and starts an increase in the amount. The cycle ends when the number reaches a minimum again. Sunspots appear in groups midway between the sun’s poles and the sun’s equator Sunspots tell us the sun rotates

Sunspot The Graph of Sunspots

Solar Wind Electrons and electrically charged particles called ions escape the solar magnetic field and move into space

Solar Ejections What are they? Atomic particles are emitted by the sun during solar events What solar events? Prominences Solar Flares Coronal Mass Ejections

Solar Ejections Prominences: Great clouds of sun’s gases from the photosphere They are caused by disturbances in the magnetic field They form Huge arches high above the sun’s surface

Solar Ejections Solar Flares: A sudden eruption of electrically charged particles It is a release of energy stored in the magnetic field of the sunspots There can be formation of coronal loops Some particles can escape into space.

Solar Ejections Coronal Mass Ejections: Electrically charged particles of the sun can escape into space. These particles are parts of the corona. CME’s strike the Earth’s magnetosphere (Earth’s magnetic field) CME’s can cause a disturbance in the Earth’s magnetic field called geomagnetic storms

The Sun Affects Our Earth Geomagnetic Storms Auroras Sunspots and Climate

Geomagnetic Storms Caused by coronal mass ejections – CME’s Sun’s particles strike the Earth’s magnetic field generating geomagnetic storms Geomagnetic storms can interfere with radio communications, damage satellites, can lead to blackouts Small storms occur each month and severe storms occur less than once per year

Auroras Electrically charged particles from the sun cluster at the Earth’s poles. These particles excite the atoms and gas molecules in the upper atmosphere causing them to glow Known as the aurora borealis or northern lights.

Climate Changes from Sunspots Affect on Earth The fewer the sunspots, the cooler the sun and the cooler the climate The more the sunspots, the hotter the sun and the warmer the climate Sunspots have a direct effect on the Earth’s climate