The Sun
The Sun's photosphere has a temperature between 4500 and 6000 K (with an effective temperature of 5777 K) and a density of about 2×10−4 kg/m3; other stars may have hotter or cooler photospheres. The Sun's photosphere is composed of convection cells called granules—cells of gas each approximately 1000 kilometers in diameter with hot rising gas in the center and cooler gas falling in the narrow spaces between them. Each granule has a lifespan of only about eight minutes, resulting in a continually shifting "boiling" pattern. Grouping the typical granules are super granules up to 30,000 kilometers in diameter with lifespans of up to 24 hours. These details are too fine to see on other stars.
Read more about this topic: Photosphere
Famous quotes containing the word sun:
“Who cares that he fell back to the sea?
See him acclaiming the sun and come plunging down
while his sensible daddy goes straight into town.”
—Anne Sexton (1928–1974)
“Croft had an instinctive knowledge of land, sensed the stresses and torsions that had first erupted it, the abrasions of wind and water. The platoon had long ceased to question any direction he took; they knew he would be right as infallibly as sun after darkness or fatigue after a long march.”
—Norman Mailer (b. 1923)