Features on the Sun
Astronomers have observed features on the Sun that vary over time.
Near the Sun’s surface there are regions of magnetic force called magnetic fields. These magnetic fields get twisted into different positions
as the Sun rotates. Features appear on the surface in areas where strong
magnetic fields are located.
are spots on the photosphere that are cooler than
surrounding areas. Although they appear dark, sunspots are actually
bright. They only seem dim because the rest of the photosphere is
so much brighter.
Sunspots
Sunspot activity follows a pattern that lasts about 11 years. At the
peak of the cycle, dozens of sunspots may appear. During periods of
low activity, there may not be any sunspots.
Sunspots move across the Sun’s surface as it rotates. Astronomers
first realized that the Sun rotates when they noticed this movement.
Because the Sun is not solid, some parts rotate faster than others.
Other solar features include flares and prominences (PRAHM-uhnuhn-sihz). Flares are eruptions of hot gas from the Sun’s surface.
They usually occur near sunspots. Prominences are huge loops of
glowing gas that extend into the corona. They occur where magnetic
fields connecting sunspots soar into the outer atmosphere.
How are sunspots different from other areas of the photosphere?
Solar Features
Features on the Sun appear in areas where a magnetic field is strong.
Sunspots
Prominences
Sunspots on the photosphere can be
larger than Earth.
Prominences can soar more than 100,000
kilometers above the photosphere.
694 Unit 5: Space Science