Superflare
Since superflares can occur on stars apparently equivalent in every way to the Sun, it is natural to ask if they can occur on the Sun itself. An estimate based on the original Kepler photometric studies suggested a frequency on solar-type stars (early G-type and rotation period more than 10 days) of once every 800 years for an energy of 10 erg and every 5000 years at 10 erg. One-minute sampling provided statistics for less energetic flares and gave a frequency of one flare of energy 10 erg every 5–600 years for a star rotating as slowly as the Sun; this would be rated as X100 on the solar flare scale. This is based on a straightforward comparison of the number of stars studied with the number of flares observed. An extrapolation of the empirical statistics for solar flares to an energy of 10 erg suggests a frequency of one in 10,000 years.
Solar cycle 24
After releasing up to nine M-class flares in only one day, the active region 1429 erupted a powerful X5.4-class flare at 00:24 UTC the March 7. The related CME impacted the Earth on March 8, causing a G3 (strong) geomagnetic storm. This event marked the second strongest solar flare of Cycle 24 in terms of X-ray flux. NOAA launched a R3 (strong) radio blackout and a S3 (strong) solar radiation storm alerts. Just one hour after that first flare, nearby sunspot 1430 released a less powerful X1.3-class one. No coronal mass ejection (CME) associated to this event was reported. Months later, in June, NASA reported that its Fermi Gamma-ray Space Telescope detected in this powerful flare the highest flux of gamma rays—greater than 100 MeV—ever associated with an eruption on the Sun.