Solar prominence
Encyclopedia
A prominence is a large, bright feature extending outward from the Sun
's surface, often in a loop shape. Prominences are anchored to the Sun's surface in the photosphere
, and extend outwards into the Sun's corona
. While the corona consists of extremely hot ionized gas
es, known as plasma
, which do not emit much visible light, prominences contain much cooler plasma, similar in composition to that of the chromosphere
. A prominence forms over timescales of about a day, and stable prominences may persist in the corona for several months. Some prominences break apart and give rise to coronal mass ejection
s. Scientists are currently researching how and why prominences are formed.
A typical prominence extends over many thousands of kilometers; the largest on record was observed by the Solar and Heliospheric Observatory
(SOHO) in 2010 and is estimated at over 700000 kilometres (434,960.9 mi) long
– roughly the radius of the Sun.
When a prominence is viewed from a different perspective so that it is against the sun instead of against space, it appears darker than the surrounding background. This formation is instead called a solar filament. It is possible for a projection to be both a filament and a prominence. Some prominences are so powerful that they throw out matter from the Sun into space at speeds ranging from 600 km/s to more than 1000 km/s. Other prominences form huge loops or arching columns of glowing gases over sunspots that can reach heights of hundreds of thousands of kilometres. Prominences may last for a few days or even for a few months. Flocculi (plural of flocculus) is another term for these filaments, and dark flocculi typically describes the appearance of solar prominences when viewed against the solar disk in certain wavelengths.
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
's surface, often in a loop shape. Prominences are anchored to the Sun's surface in the photosphere
Photosphere
The photosphere of an astronomical object is the region from which externally received light originates. The term itself is derived from Ancient Greek roots, φῶς, φωτός/phos, photos meaning "light" and σφαῖρα/sphaira meaning "sphere", in reference to the fact that it is a spheric surface perceived...
, and extend outwards into the Sun's corona
Corona
A corona is a type of plasma "atmosphere" of the Sun or other celestial body, extending millions of kilometers into space, most easily seen during a total solar eclipse, but also observable in a coronagraph...
. While the corona consists of extremely hot ionized gas
Gas
Gas is one of the three classical states of matter . Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point , boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons...
es, known as plasma
Plasma (physics)
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
, which do not emit much visible light, prominences contain much cooler plasma, similar in composition to that of the chromosphere
Chromosphere
The chromosphere is a thin layer of the Sun's atmosphere just above the photosphere, roughly 2,000 kilometers deep....
. A prominence forms over timescales of about a day, and stable prominences may persist in the corona for several months. Some prominences break apart and give rise to coronal mass ejection
Coronal mass ejection
A coronal mass ejection is a massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space....
s. Scientists are currently researching how and why prominences are formed.
A typical prominence extends over many thousands of kilometers; the largest on record was observed by the Solar and Heliospheric Observatory
Solar and Heliospheric Observatory
The Solar and Heliospheric Observatory is a spacecraft built by a European industrial consortium led by Matra Marconi Space that was launched on a Lockheed Martin Atlas IIAS launch vehicle on December 2, 1995 to study the Sun, and has discovered over 2100 comets. It began normal operations in May...
(SOHO) in 2010 and is estimated at over 700000 kilometres (434,960.9 mi) long
– roughly the radius of the Sun.
When a prominence is viewed from a different perspective so that it is against the sun instead of against space, it appears darker than the surrounding background. This formation is instead called a solar filament. It is possible for a projection to be both a filament and a prominence. Some prominences are so powerful that they throw out matter from the Sun into space at speeds ranging from 600 km/s to more than 1000 km/s. Other prominences form huge loops or arching columns of glowing gases over sunspots that can reach heights of hundreds of thousands of kilometres. Prominences may last for a few days or even for a few months. Flocculi (plural of flocculus) is another term for these filaments, and dark flocculi typically describes the appearance of solar prominences when viewed against the solar disk in certain wavelengths.
See also
- Coronal mass ejectionCoronal mass ejectionA coronal mass ejection is a massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space....
- Solar flareSolar flareA solar flare is a sudden brightening observed over the Sun surface or the solar limb, which is interpreted as a large energy release of up to 6 × 1025 joules of energy . The flare ejects clouds of electrons, ions, and atoms through the corona into space. These clouds typically reach Earth a day...
- CoronaCoronaA corona is a type of plasma "atmosphere" of the Sun or other celestial body, extending millions of kilometers into space, most easily seen during a total solar eclipse, but also observable in a coronagraph...