The results of the Stanford scientists show that sunspots are generated at least 60,000 km below the surface and emerge from this depth up to the surface with an average speed of 0.3-0.6 km/s. The detection of sunspots in the solar interior may lead to significant advances in space weather forecasting. The technique that they used to detect the sunspots is called “time-distance helioseismology”, which is similar to an approach widely used in earthquake studies. Just as seismic waves traveling through the body of Earth reveal what is inside the planet, acoustic waves traveling through the body of the Sun can reveal what is inside the star. Submerged sunspots have a detectable effect on the sun's inner acoustics—namely, sound waves travel faster through a sunspot than through the surrounding plasma. A big sunspot can leapfrog an acoustic wave by 12 to 16 seconds.
le macchie solari risultano generate ad almeno 60000 km di profondita
come le onde sismiche viaggiano attraverso la terra rivelandone l'interno, le onde acustiche viaggiano attraverso il sole, le onde sonore viaggiano piu veloci attraverso le macchie solari di quanto facciano attraverso il plasma circostante.