Chapter 29-2 Solar Activity
Solar Activity Gases in constant motion (rising and sinking) Sun rotates on axis
Not a solid Ball of hot gases Close to equator – 25.3 Earth days to rotate once Poles – 33 days Average – 27 days
Sunspots Gases in convection zone + Sun’s rotation = Magnetic Field Cause convection currents to slow in areas Cooler areas
Sunspots Shine bright but less than surrounding areas Appear darker Located in Photosphere
Granulation – grainy appearance of Photosphere
Sunspot Cycle Observation of sunspots show Sun’s rotation 11 year cycle Start with few Increases to 100 Then start to diminish
Solar Ejections Caused by change in magnetic field Sun atomic particles Prominences Solar flares Coronal mass ejections
Prominences Clouds of glowing gases Arch above surface Follow curve of magnetic forces Lasts hours to weeks
Solar Flares Most violent Outward eruption of charged particles Release of energy from sunspots Thousands of meters
Coronal Mass Ejection Parts of the corona that are thrown off the sun Particles can strike Earth’s magnetosphere Cause geomagnetic storms
Interfere with radio communication Damage satellites Blackouts
Auroras Interaction between solar winds and Earth’s magnetic field Bands of light
Charged particles from sun hit atoms of gas in upper atmosphere Produce sheets of light
Northern Lights – Aurora Borealis
Southern Lights – Aurora Australis
100 – 1,000 km above surface Visible in US – 4 to 5 times a year Alaska – much more frequent Seen from space Jupiter and Saturn