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A spicule is a small temporary jet on the surface of the Sun, outward from the photosphere. They are very common (ubiquitous), with typically on the order of three million in progress at any moment, spread throughout the surface, covering about 1%. They last about 15 minutes and reach heights of thousands of kilometers. Their diameter is on the order of 300 km, their velocity is on the order of tens of km/s and their mass flux density is 100 times that of the solar wind. The material generally falls back to the surface, but does contribute material to the chromosphere and solar wind. The mechanism producing them is still of research interest.