Scientists think they have discovered the energy source of auroras borealis and australis, the spectacular upper atmospheric color displays seen in the highest latitudes of the our planet. At the same time, this discovery raises questions about our understanding of Total Solar Irradiance (TSI).
Results were presented Tuesday at the American Geophysical Union (AGU) meeting. NASA has a press release on their science site
New data from NASA’s Themis mission, a quintet of satellites launched this winter, found the energy comes from a stream of charged particles from the sun flowing like a current through twisted bundles of magnetic fields connecting Earth’s upper atmosphere to the sun. The energy is then abruptly released in the form of a shimmering display of lights.
Estimates of the total energy of a two-hour auroral event they studied are at five hundred thousand billion (5 x 10^14) Joules. That’s approximately equivalent to the energy of a magnitude 5.5 earthquake.
“The satellites have found evidence for magnetic ropes connecting Earth’s upper atmosphere directly to the Sun,” says Dave Sibeck, project scientist for the mission at the Goddard Space Flight Center. “We believe that solar wind particles flow in along these ropes, providing energy for geomagnetic storms and auroras.”
One of the things that has always bothered me about the claims that Total Solar Irradiance (TSI) variance can’t account for climatic changes is that it only considers the visible output of the sun, yet the sun has many mechanisms for transferring energy to the earth. Now we find another, magnetic ropes.
Our planet is bathed in the sun’s ultraviolet, solar wind, and magnetic field variances, yet these are not considered in the most common equations or modeling of earth’s total energy budget from the sun. Given that we’ve just learned something new about how the sun transfers energy to earth, I’d say that the TSI numbers that are commonly tossed about by climate modelers and their proponents are lacking in a total understanding of the sun to earth energy transfer.
To me, the fact that the suns magnetic field is linked more closely to earth now lends credence to theories like that of Henrik Svensmark, which points to an extraterrestrial driver of climate change, cosmic rays which form cloud nuclei in our atmosphere, modulated by solar variance. Given the “magnetic ropes” discovery announcement this week, I believe there are processes that transfer energy to our planet or modulate it’s energy balance that we haven’t yet discovered. In doing measurements in situ of our planets energy balance we need to look beyond just our atmosphere, because that’s the real and total in situ environment.
As Jack Horkheimer always used to say as he ended his astronomy program, ”Keep looking up!”.