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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.
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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
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
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