Sunspots spawn solar flares that can cause billions of dollars in damage to satellites, communications networks and power grids. But Stanford researchers have developed a way to detect incipient sunspots as deep as 65,000 kilometers inside the sun, providing up to two days' advance warning of a damaging solar flare.
The first 10 seconds of the movie show intensity observations of the Sun. The intensity later fades out and the photospheric magnetic field is shown. In the next 20 seconds, we zoom in to a region where a sunspot group would emerge. The upper layer shows magnetic field observations at the surface and the lower layer shows simultaneous travel-time perturbations, detected at a depth of about 60,000 km.
After the emergence, intensity observations show the full development of this active region, until it rotates out of view on the west solar limb. (movie made by Thomas Hartlep)