The Solar System

162 PART 2^ |^ THE STARS

Quiescent prominences may hang in the lower

corona for many days, whereas eruptive

prominences burst upward in hours. The eruptive

prominence below is many Earth diameters long.

Aprominence is composed of ionized gas

trapped in a magnetic arch rising up through

the photosphere and chromosphere into the lower

corona. Seen during total solar eclipses at the edge

of the solar disk, prominences look pink because of

the three Balmer emission lines. The image above

shows the arch shape suggestive of magnetic

fields. Seen from above against the sun’s bright

surface, prominences form dark filaments.

Trace/NASA

SOHO, EIT, ESA and NASA

Sacramento Peak Observatory

NOAA/SEL/USAF

Far-UV image

Earth shown

for size comparison

H-alpha filtergram

The gas in prominences

may be 60,000 to 80,000 K,

quite cold compared with

the low-density gas in the

corona, which may be as

hot as a million Kelvin.

The gas in prominences

may be 60,000 to 80,000 K,

quite cold compared with

the low-density gas in the

corona, which may be as

hot as a million Kelvin.

1

1b

1a

Magnetic phenomena in the chromosphere

and corona, like magnetic weather, result as

constantly changing magnetic fields on the sun trap

ionized gas to produce beautiful arches and powerful

outbursts. Some of this solar activity can affect Earth’s

magnetic field and atmosphere.

This ultraviolet image of the solar surface was made

by the NASA TRACE spacecraft. It shows hot gas

trapped in magnetic arches extending above active

regions. At visual wavelengths, you would see sunspot

groups in these active regions.

Magnetic phenomena in the chromosphere
and corona, like magnetic weather, result as
constantly changing magnetic fields on the sun trap
ionized gas to produce beautiful arches and powerful
outbursts. Some of this solar activity can affect Earth’s
magnetic field and atmosphere.

This ultraviolet image of the solar surface was made
by the NASA TRACE spacecraft. It shows hot gas
trapped in magnetic arches extending above active
regions. At visual wavelengths, you would see sunspot
groups in these active regions.

Hα image

Filament