CH. 29.2 – Solar Activity CH. 29 - MARQUES

Terms to know…

Sunspot Prominence Granules solar flare coronal mass ejection aurora

Solar Activity

Sun rotates on its own axis once per 27 days

Gases are in constant motionGranules are just the grainy

appearance of the sun and result from small temp/density differences.

Sunspots

Sunspots: areas of slower convection (high magnetism) Vary in size...up to >7x the

size of Earth! …showed scientists that the sun does rotate.

Sun Spot Cycle

1. Low # of sunspots (groups) begins to increase2. Appear in groups halfway between equator and poles.3. Higher latitude sunspots begin to disappear and new ones appear at/near the equator. 4. At approx. 11 years, the number of groups begins to increase again.

Solar Eruptions

Prominences: glowing HOT gas from chromosphere form arches with curved magnetic field lines. (lasts weeks or hours) 

Solar Flares: sudden/violent/HOT/eruption of ions (e-, p+) lasts minutes or an hour...

releases E stored in the magnetic fields from sunspots…

can form coronal loops.

Can reach temp of 20 mil oC!

Solar Eruptions Cont…

Coronal Mass Ejections: parts of the corona that get thrown off!

particles can strike and disturb Earth’s magnetosphere (geomagnetic storm)

can knock out power grids.

Solar Eruptions Cont…

Auroras: interaction of solar wind and the magnetosphere. Mostly seen @ poles b/c that’s where

magnetism is greatest.

Ions strike gas particles in our atmosphere, causing sheets of light.

Peak at the height of sunspot cycle, especially after flares. Why?

Northern lights (aurora borealis)

Southern lights (aurora australis)