23 October 2015
Typical solar flares are finished in a matter of minutes. On October 22nd (2015), a solar flare in the magnetic canopy of sunspot AR2434 lasted for more than 3 hours.
NASA's Solar Dynamics Observatory recorded the eruption:
Richter Scale of Solar Flares it
registered only C4.5. What the flare lacked in amplitude, however,
it made up for in longevity. The hours-long blast was powerful and
produced a bright CME, shown here (above video) billowing away from
the sun's southwestern limb.
NOAA forecast models suggest that the cloud will deliver a glancing blow to our planet's magnetic field on October 25th. There is a 50% chance of G1-class geomagnetic storms when it arrives.
Weekend auroras, anyone?