Free Republic

The Sun runs on an 11-year cycle of rising and falling activity, tracked mainly by counting sunspots – the dark patches scattered across its surface. Solar Cycle 25, the current cycle, was forecast as mild, and the sunspot count agreed. But those counts read only the surface. A global network of six telescopes has listened to the Sun’s interior for nearly 40 years, and what it is now telling researchers is not what the surface suggested at all. Listening inside the Sun Scientists have a name for eavesdropping on those sound waves: helioseismology. The waves are trapped inside the Sun,...

Enlarge ImageWake-up call. The sun's jet streams (in red, right) have reached their critical position, and soon the first sunspots of the new solar cycle may mar the star's currently placid-looking surface (inset).Credit: National Solar Observatory/GONG (main image); SOHO/MDI (inset) Maybe old Sol didn't hear the alarm clock. After a mysterious 2-year delay, the next 11-year solar cycle seems ready to begin, scientists say. That means the reemergence of sunspots, and with them periodic electromagnetic assaults on global navigation, communications, and power supplies--as well as brilliant auroras in the polar regions. For unknown reasons, the sun goes through cycles...

Inside the sun: more than just a glowing ball The unusually long quiet period of the Sun’s present activity may be due to the motion of “sluggish” jet streams beneath the solar surface, according to scientists at the National Solar Observatory (NSO) in Arizona, US. The scientists’ observations, which show an east–west jet stream has taken a year longer to migrate south by 10° than in the previous solar cycle, also indicate that the sun is moving into its next cycle. “We need to continue these observations for many, many more years to fully understand what is going on,” said...