On February 15, 2011, researchers spied two sunquakes and a solar flare that occurred around the same time—but the flare wasn’t hot enough to have spawned the seismic waves.
“The heat and radiation from solar flares is thought to drive a pressure wave to the surface, like thunder from a lightning bolt. But for this February 15th event, it wasn’t like that,” said Sergei Zharkov, a space scientist at University College London, who presented the new findings about sunquakes last month at the2012 National Astronomy Meeting in Manchester, U.K.
Instead it appears the February sunquakes were linked to a coronal mass ejection, or CME, a huge cloud of charged solar particles that erupted from the sun’s upper atmosphere.
It wasn’t until 1998, however, that a team of scientists announced the first observed sunquake, found in 1996 data from NASA’s Solar and Heliospheric Observatory. The 11.3-magnitude sunquake occurred following a solar flare, and it was 40,000 times more powerful than the 1906 San Francisco earthquake.
In addition, more and better sun-monitoring satellites are in place now than ever before.
The “most beautiful data,” Zharkov said, comes from NASA’s Solar Dynamics Observatory (SDO), which launched in 2010. That spacecraft will provide the best views yet of increasingly common sunquakes, he said.
“These sunquakes,” Zharkov said, “are part of the puzzle of flares and coronal mass ejections, which have the most direct impact on space weather” that can disrupt satellites and cause auroras.
Zharkov’s ultimate dream is to use sunquakes to “see” inside the sun, in much the same way seismologists use earthquakes to probe inside our planet.
“Sunquakes travel through the solar interior and contain some info about it,” he said. “We’d like to capture that information to see below the sun’s surface.”