A moderate solar flare was emitted by the sun on July 19, 2012. At 5:58 UTC it peaked at M7.7 on the flare scale, which makes it fairly powerful, but still much weaker than X-class flares, which are the largest. What made this particular event so noteworthy was the associated activity in the sun's corona. For the next day, hot plasma in corona cooled and condensed along the strong magnetic fields of the region that produced the flare. Magnetic fields are invisible, but the plasma is very obvious in the extreme ultraviolet wavelength of 304 angstroms, which highlights material at a temperature of about 50,000 Kelvin. This plasma is attracted to the magnetic fields and outlines them very clearly as it slowly falls back to the solar surface. This process of condensing plasma falling to the surface is called coronal rain.
The footage in this video was collected by the Solar Dynamics Observatory's AIA instrument. SDO collected one frame every 12 seconds so each second in this video corresponds to 6 minutes of real time. The video covers 4:30 UTC on July 19th to 2:00 UTC on July 20th, a period of 21 hours and 30 minutes.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 220.127.116.11.0