Sunday, 19 February 2012

Mystery: Auroras Observed Without Solar Flare!

On February 14, a series of weird atmospheric events was observed over portions of the northern hemisphere. Scientists noticed auroras (northern lights) shining brighter than usual, even if no solar flares were previously reported to have occurred on the surface of the Sun.

The dazzling light show the auroras put on this week is one of the most bizarre manifestations scientists ever came across. Thus far, they were convinced that spikes in northern light intensity were directly correlated to the emergence of solar flares and coronal mass ejections.

These events produce vast amounts of charged electrical particles, which then travel from the Sun towards our planet. Once they come across the magnetosphere, they begin to flow alongside magnetic field lines, producing the amazing lights our planetary poles are famous for. 

But this explanation does not allow for auroras to..

spike in intensity and brightness without solar eruptions having occurred beforehand. What researchers saw this week was the planetary magnetic field experiencing such an increase in activity that it produced a geomagnetic storm.

“Sometimes the sky surprises us. On [Ebruary] 14-15, with little warning, geomagnetic activity rippled around the Arctic Circle, producing an outbreak of auroras that veteran observers said was among the best in months,” astronomer Tony Phillips said for Spaceweather.

He explained that there have been some unconfirmed reports of a coronal mass ejection (CME) having occurred on February 10. However, the data have not yet been substantiated by direct evidence from the multiple spacecraft currently keeping an eye on the Sun, Space reports.

“The reason for the outburst is still not completely clear. No CME was obvious in local solar wind data at the time; the disturbance just […] happened,” a February 16 post on the same website explains.

According to solar physicists, we are currently nearing the end of Solar Cycle 24. Our parent star operates in 11-year cycles, where periods of high activity called maximums alternate with calmer ones, called minimums.

Between 2012 and 2013, the Sun is expected to undergo a maximum, meaning that the number of CME and solar flares it will produce will increase considerably over the next couple of years.

No comments:

Post a Comment