Spicules

from Wikipedia, the free encyclopedia

Spicules ( lat. Spiculum "tip", "spit"; plural spicula ) are tube- like, eruptive phenomena on the chromosphere of the sun and probably other stars as well . They were discovered at the edge of the sun during the solar eclipse in 1877 and appear as high- speed , upward-directed gas splashes. As was only recognized around 1950, it is solar river channels that are particularly concentrated at sunspots . They are caused by the strong convection under the sun's surface ( photosphere ), which transports the radiant heat from the inside of the sun to the outside.

Quantitative description

Spicules have a diameter of a few 100 to 1,000 kilometers, can be 10,000 km long and shoot up at up to 150 kilometers per second. Research with high-speed cameras has shown that the spicules last for an average of about five minutes. They start out as small tubes of rapidly rising gas, but fade when the gas has reached its highest point and falls back towards the sun.
Magnetic tensions just below the visible solar surface are responsible, which are amplified and transported upwards. When these discharge, they hurl streams of gas along the magnetic field lines , which heat up strongly in the process. Accordingly, the coils not only enrich the solar corona with plasma , but also contribute to its extremely high temperatures. The temperature of the spicules is several million Kelvin .

The formation and the play of forces of the spicules is still unclear in detail.

Interpretations

Angelo Secchi SJ from the Vatican Observatory gave a very clear interpretation of the phenomenon he discovered . He compared the chromosphere that can be seen at the edge of the sun in eclipses with huge bushfires or a burning prairie . The chromosphere grows out of an even sublayer (i.e. out of the photosphere) and gives the impression that flames are constantly beating up.

The solar researchers Otto Kiepenheuer turns "the splashes or the entire (relatively thin) Chromosphere as spray of the billowing Photo sphere Ocean" with its ever upward flowing granulation - swirls before. Just as the light splashes of the ocean surf develop much higher speeds than the heavy waves of the sea, the spikule splashes are also very much faster than the flow processes in the much denser photosphere. This picture essentially corresponds to the processes on shock fronts that can be easily calculated today .

Individual evidence

  1. ↑ starobserver.org: Spikulen: Rays on the Sun , APOD November 2, 2010.
  2. ↑ Spektrum.de June 22, 2017
  3. ↑ mirok.de: sun
  4. ^ Karl Otto Kiepenheuer: Die Sonne , Springer-Verlag, Berlin and Heidelberg 1957, p. 56 f.

Web links