Solar Scales Light How Does Energy Get from the Sun to Us? The Sun in Different Kinds of Light 1/r 2 law Space Weather STEREO Living and Working in Space: Energy The Sun Terry Kucera Scientist with the STEREO and SOHO Missions NASA/GSFC

Sun Scale Facts: You can fit 109 Earths across the disk of the Sun Driving at a speed of 55 mph it would take almost 200 years to drive from Earth to the Sun

Energy Moves Through The Sun Core Where the energy is created. Nuclear reactions burn every second about 700 million tons of hydrogen into helium. Radiative Zone Where energy is transported by radiation. Although the photons travel at the speed of light, they bounce so many times through the dense material that they use about a million years to escape the Sun. Convection Zone Energy transported by convection (just like boiling soup) where heat is transported to the photosphere. Surface Energy is radiated as light through the almost vacuum of space

Energy Moves Through The Sun Core Where the energy is created. Nuclear reactions burn every second about 700 million tons of hydrogen into helium. E=mc 2

Energy Moves Through The Sun Radiative Zone Where energy is transported by radiation. Although the photons travel at the speed of light, they bounce so many times through the dense material that they use about a million years to escape the Sun. 170,000 yrs for photons Over 1 million yrs for a heating change

Energy Moves Through The Sun Convection Zone Energy transported by convection (just like boiling soup) where heat is transported to the photosphere. 10 yrs for the photon

Energy Moves Through The Sun Surface Energy is radiated as light through the almost vacuum of space at the speed of light - just over 8 minutes from Sun to Earth

At the distance of 149,600,000 km (1.00 AU) from Sun the intensity of all the Sun’s light is kW/m 2. This varies by less than 0.1% because of solar variability. It changes by almost 7% due to the change in distance of the Earth from the Sun over the course of the year. Intensity of Sunlight Reduces as the Square of the Distance from the Sun

Electromagnetic Spectrum

The Sun: Visible Light, Sept. 22, 2000 SOHO/MDI

The Sun: Radio Waves Sept. 22, 2000 Nobeyama 17 GHz

The Sun: Ultraviolet Light, Sept. 22, 2000 SOHO/EIT 286 A

Visible Light Solar Spectrum

The Sun Radiates More than Just Light SOHO/LASCO, ESA & NASA The Sun’s Corona in Visible Light

SOHO Observations of the flares and Coronal Mass Ejections of Halloween 2003

The Earth is protected by its magnetic field and atmosphere

STEREO Launch Oct. 25, 2006