Earthquakes in Space

29 Jul 2010

http://wattsupwiththat.com/2010/07/27/space-quakes/ and www.physorg.com/print199554868.html 'Spacequakes Rumble Near Earth' (with video clip, on both sites). Researchers making use of NASAs five THEMIS imaging spacecraft have discovered what they call 'space quakes' which are then described as 'space weather' with the 'punch of an earthquake'. They play a role in aurora, a temblor in earth's magnetic field, and the effects can reach all the way down to the surface of the earth. In the literature they are magnetic reverberations detected at ground stations much like seismic detectors measure earthquake activity. The amount of energy in a spacequake is very similar to magnitude 5 to 6 earthquakes according to a paper in Geophysical Research Letters April 2010. Spacequakes begin in earth's magnetic tail which is stretched out somewhat like a windsock by the solar wind. When it is stretched too far the magnetic tail snaps back like a rubber band and streams of plasma in the solar wind drop towards the earth causing spacequakes. A further parallel is drawn - when the earth's magnetic field shakes in a similar way to the shaking of the ground during an earthquake - but at an altitude of 30,000km above the equator, the impact sets off a rebending process in which the plasma can be seen (THEMIS imaging) to bounce up and down on the reverberating magnetic field. This process is now known as 'repetitive flow rebuffing' but the first bounce is the big one. THEMIS imaging also shows plasma vortices - huge swirls of magnetised gas as wide as the earth itself, spinning on the verge of the quaking magnetic field. It is thought the vortices generate a substantial electric current in the atmosphere. Vortices also have tails and these fanned particles into earth's atmosphere sparking auroras and making waves of ionisation that disturb electronic gadgetry and radio communications. Space quakes appear to generate electric currents on the ground as ground current surges have been noted - and theoretically these could affect power grids.

The Los Alamos National Laboratory conducted a computer simulation of the THEMIS data and reproduced vortices. The simulation suggests the rebounding process can be seen from earth's surface in the form of ripples and whirls in auroral displays. It all fits together, a spokesman adds - so eat your heart out the EU detractors. Science is discovering we don't know as much as we think we do know. It might also be bad news for AGW theory - plasma adds energy to the atmosphere = a warmer climate ? Perhaps.