An ''sunquake'' 40,000 times more powerful than the earthquake which devastated San Francisco in 1906 has been observed by scientists, it was disclosed today.
The discovery was the first proof that solar flares produce seismic waves in the sun's interior similar to terrestrial earthquakes.
However, a quake on the sun is on a different scale from any on earth. The one spotted by the Solar and Heliospheric Observatory (SOHO) spacecraft produced waves nearly two miles high travelling at 250,000 mph over the sun's surface.
The quake, following a moderate-sized solar flare on July 9 1996, appeared like ripples spreading from a rock dropped into a pool of water.
The massive solar waves travelled a distance equal to 10 times the diameter of the Earth over the course of an hour, before fading.
The waves accelerated from an initial 22,000 miles per hour to reach a maximum speed of 250,000 mph.
Scientists said the amount of energy unleashed by the sunquake was enough to power the United States for 20 years.
They suggested that other stars which also produce flares releasing X- ray radiation might be shaken by even more powerful ''starquakes''.
The findings were reported in the science journal Nature today by researchers from Glasgow University and Stanford University, California. …