What Is a Spicule on the Sun?

Discovery of Solar Spicules

• Solar spicules were discovered in 1877 by Father Angelo Secchi, who was working with the Vatican Observatory in Rome. Since then, astrophysicists have struggled to explain this solar phenomenon, and have devised many theories in an attempt to do so.

Basic Facts

• Solar spicules leap from the surface of the sun at speeds of up to 81,000 kilometers per hour (50,000 miles per hour), and can reach heights of up to 5,000 kilometers (3,000 miles) above the surface. In spite of their consistency, spicules have diameters of, at most, 500 kilometers (300 miles), and vanish within five minutes. Because of this, solar spicules have often proved difficult to study.

Birth of Solar Spicules

• Solar spicules are thin tubes of plasma. They are held together magnetically, confining the plasma to a tube. Traditional understanding teaches that spicules are produced by activity that occurs in the sun's core, which creates a magnetic field that attracts plasma and accelerates its course towards the outer areas of the sun. When the magnetically-confined tube reaches the surface of the sun, it has gained enough velocity to protrude from the surface, creating a solar spicule.

An Alternate Theory

• In 2004, an alternate theory was published. It suggested that solar spicules are instead caused by a regulative rhythmic cycle. Sound waves trapped inside of the sun create seismic activity on the surface. When the waves are able to leak outside, shock waves are created that blast matter into the corona, yielding solar spicules.

Effects of Solar Spicules

• Astrophysicists believe that solar spicules contribute to the creation of solar wind. Solar wind originates from the sun, and is a constant flow of charged particles. These particles envelop the earth, and can cause damage to satellites, among other things.