The Sun interacts with the Earth throughThe Sun interacts with the Earth throughElectromagnetic RadiationElectromagnetic Radiation

andandThe The Solar Solar WindWind

Image courtesy of National Aeronautics and Space Administration (NASA)

Electromagnetic RadiationElectromagnetic Radiation

Travels at the speed of light, 300,000 km/s (186,000 mi/s)

Takes approximately 8 minutes to reach the Earth

Image courtesy of Occupational Safety & Health Administration (OSHA)

The Solar WindThe Solar Wind

Consists of charged Consists of charged particles (protons and particles (protons and electrons)electrons)

Takes several days to Takes several days to reach the earthreach the earth

Average density is 5Average density is 5--10 particles per cubic 10 particles per cubic centimetercentimeter

Courtesy of SOHO/EIT consortium. SOHO is a project of international cooperation between ESA and NASA

Sun Structure

Image courtesy of National Aeronautics and Space Administration (NASA)

The CoreThe Core

It’s HOT!!!! 15 It’s HOT!!!! 15 Million degrees Million degrees KelvinKelvin

It’s DENSE!!!! 10 It’s DENSE!!!! 10 times more dense times more dense than leadthan lead

And……Image courtesy of Tungsten Heavy Powder, Inc.

FusionFusion

At that temperature At that temperature and density, nuclear and density, nuclear fusion occursfusion occurs

Fusion is the source Fusion is the source of the sun’s of the sun’s electromagnetic electromagnetic radiationradiation

Image courtesy of the Lawrence Berkeley National Laboratory

Did You Know?Did You Know?

The sun converts The sun converts 5 million tons 5 million tons of matter into of matter into energy every energy every second.second.

RadiativeRadiative ZoneZoneEnergy is Energy is transported from transported from the core through the core through radiationradiation

Energy is Energy is constantly constantly absorbed and reabsorbed and re--emitted by atomsemitted by atoms

Courtesy of SOHO/EIT consortium. SOHO is a project of international cooperation between ESA and NASA

It’s a LONG RoadIt’s a LONG Road

It takes thousands to It takes thousands to millions of years for millions of years for the energy released by the energy released by the fusion process to the fusion process to reach the sun’s reach the sun’s convective zoneconvective zone

Image credit Yohkoh Public Outreach Project

Convective ZoneConvective Zone

Energy transfer is Energy transfer is similar to motion of similar to motion of boiling water in a potboiling water in a pot

Hot interior gases Hot interior gases move outward as move outward as cooler gases sinkcooler gases sink Image courtesy of the Alder Planetarium

Layer of the Sun we see

Visible sunspots

Exhibits granulation

PHOTOSPHERE

Image courtesy of Space Science News

Solar GranulesSolar Granules

Visible proof of Visible proof of convection zoneconvection zone

Masses of hot gas that Masses of hot gas that rise and fall rise and fall

Each granule is about Each granule is about the size of an earth the size of an earth continent continent

Image courtesy of National Aeronautics and Space Administration (NASA)

Sun’s outer atmosphere

Temperature rises to millions of degrees K

Extends millions of kilometers into space

CoronaCorona

Image courtesy of National Aeronautics and Space Administration (NASA)

Did You Know?Did You Know?

The Sun’s corona The Sun’s corona or atmosphere is or atmosphere is hundreds of times hundreds of times hotter than its hotter than its surfacesurface

Image courtesy of National Aeronautics and Space Administration (NASA)

Solar EventsSolar Events

Sun spotsSun spots

Solar flaresSolar flares

Coronal mass Coronal mass ejections (CME’s)ejections (CME’s)

Courtesy of SOHO/EIT consortium. SOHO is a project of international cooperation between ESA and NASA

Sun SpotsSun Spots

Cool areas of the Cool areas of the photospherephotosphere

Number varies in Number varies in approximate 11 year approximate 11 year solar cyclesolar cycle

Produced by local Produced by local solar magnetic fieldssolar magnetic fields Size of Earth

Courtesy of SOHO/MDI consortium. SOHO is a project of international cooperation between ESA and NASA

Solar FlaresSolar Flares

Most occur in and Most occur in and around sun spotsaround sun spots

Frequency follows Frequency follows solar cyclesolar cycle

Source of dangerous Source of dangerous levels of radiationlevels of radiation

solar flare

Courtesy of SOHO/EIT consortium. SOHO is a project of international cooperation between ESA and NASA

Coronal Mass Ejection (CME)Coronal Mass Ejection (CME)

Eruption of large Eruption of large bubble of solar bubble of solar materialmaterial

Creates the most Creates the most adverse effect on adverse effect on Earth’s Earth’s magnetospheremagnetosphere

Courtesy of SOHO/LASCO consortium. SOHO is a project of international cooperation between ESA and NASA

Two main components of the earth system affected by solar activity are:

The earth’s ionosphere (upper atmosphere)

The earth’s magnetic field, called the magnetosphere

The Structure of the Earth

Image credit – The Canadian Space Agency http://www.space.gc.ca/

Image courtesy of National Aeronautics and Space Administration (NASA)

The IonosphereThe IonosphereFar above the area in Far above the area in which we livewhich we live

Layer of the earth's Layer of the earth's atmosphere that is atmosphere that is ionized by solar radiation ionized by solar radiation

Plays a significant role in Plays a significant role in radio, television, and radio, television, and satellite communicationssatellite communications

Courtesy of Windows to the Universe, http://www.windows.ucar.edu

The MagnetosphereThe Magnetosphere

Area of space around the Area of space around the Earth that is controlled by Earth that is controlled by the Earth's magnetic fieldthe Earth's magnetic field

Shape is the direct result Shape is the direct result of being blasted by solar of being blasted by solar wind wind

Protects us from most of Protects us from most of the harmful effects of the harmful effects of space weatherspace weather

Image courtesy of National Aeronautics and Space Administration (NASA)

Space WeatherSpace Weather

The condition of the The condition of the space environment space environment influenced by the suninfluenced by the sun

Earth consequences Earth consequences can be beautiful but can be beautiful but disruptive disruptive

Image courtesy of Stanford Solar Center

Aurora BorealisAurora BorealisAlso known as the Also known as the northern lightsnorthern lights

Solar wind excites Solar wind excites gases in the gases in the ionosphereionosphere

Most common sign Most common sign of space weather of space weather activityactivity Image courtesy of National Aeronautics and Space

Administration (NASA)

Did You Know?Did You Know?During a major During a major solar storm, solar storm, auroras can be auroras can be seen as far south seen as far south as Florida, Texas, as Florida, Texas, and even Mexicoand even Mexico..

Image courtesy of National Aeronautics and Space Administration (NASA)

Satellite, communications, and Satellite, communications, and power disturbancespower disturbances

Image courtesy of National Aeronautics and Space Administration (NASA)