Structure of the Sun & Solar Activity

Parts of the Sun Core: enormous pressure & high temperatures cause the fusion of hydrogen into helium (15 million ºC) Corona: very hot, creates solar wind, only visible during a solar eclipse (1 million ºC) Photosphere: innermost layer of atmosphere – VISIBLE LIGHT (6 thousand ºC) Radiation Zone: energy from the core moves through the radiative zone in the form of electromagnetic radiation (2-7 million ºC) Convective Zone: hot gasses move outward, cool, contract, sink, repeat (2 million ºC) Chromosphere: gives off redish light from Hydrogen (4-50 thousand ºC)

Solar Activity (not part of your notes) The sun is in constant motion. Parts of the sun rotate faster than others. The equator moves the fastest, the poles the slowest. It takes an average of 27 days for the sun to make one rotation.

Sunspots Dark areas of the photosphere of the sun, that are cooler than the surrounding areas, and have a strong magnetic field. Caused by magnetic fields created through the movement of gasses (rotation and convection). The sunspot cycle lasts 11 years.

Sunspot Cycle Graph 11 years from low to low

2008 also experienced a 50 year low in solar wind pressure. SUNSPOTS Sept 27, 2001 Sept 27, 2008 (200+ days with no sunspots) 2008 also experienced a 50 year low in solar wind pressure.

Solar Activity (Ejections) Affected by the sunspot cycle Solar Ejections are when the sun emits atomic particles: Prominences Solar Flares Coronal Mass Ejections (CME’s)

Erupting Prominences Huge arches of glowing gasses that connect areas (in the sun’s atmosphere) that have positive magnetic energy to areas with negative magnetic energy. Caused by the same magnetic fields that create sunspots. http://search.nasa.gov/centers/goddard/mpg/133251main_trace_640x480.mpg

Prominences

Coronal Mass Ejection Particles (or parts of the corona) are thrown off the sun. Strike Earth’s magnetosphere creating disturbances called geomagnetic storms. Geomagnetic storms can disturb radio communication, damage satellites and cause auroras.

Earth’s Magnetosphere

Earth’s Magnetosphere A magnetic field surrounding the earth – affected by solar wind and the magnetic fields of other space objects. Protects the majority of the Earth from the solar wind. Solar wind is a stream of electrically charged particles (protons & electrons) flowing from the sun.

Solar Wind

Computer Animation of a CME creating Auroras on Earth – notice Earth’s magnetosphere. (Wait for animation to start )

Solar Flares Sudden outward eruption of charged particles The trigger is unknown. During a peak , 5-10 can occur in one day Particles that escape will increase the strength of the solar wind

Geomagnetic Storm Effects Radiation Hazards to humans – especially those in space Migratory animals less able to navigate (esp. homing pigeons) Communication Disruptions: ground-to -air, ship-to-shore, shortwave broadcast, and amateur radio.

Geomagnetic Storm Effects GPS & Loran navigation disruptions Satellite hardware damage Power Grid Outages – 1989 Quebec & NE US was out for 9 hours (affecting 6 million people)

Examples for Foldable