The sun emits a powerful eruption of radiation – a solar eruption in the X1 class

SDO Solar Flare October 28, 2021

NASA’s Solar Dynamics Observatory captured this image of a solar eruption – as seen in the bright flash at the lower center of the Sun – on October 28, 2021. The image shows a subset of extremely ultraviolet light highlighting the extremely hot material in flares, which is colored here in blue-green. Credit: NASA / SDO

The sun emitted a significant solar flare that peaked at. 11:35 EDT on October 28, 2021. NASA‘s Solar Dynamics Observatory, which keeps an eye on the Sun constantly, took a picture of the event.

Solar eruptions are powerful eruptions of radiation. Harmful radiation from a flare cannot pass through the Earth’s atmosphere to physically affect humans on Earth, but – when they are intense enough – they can disrupt the atmosphere in the layer where GPS and communication signals travel.

This flare is classified as an X1 class flare.

The X-Class denotes the most intense flare, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc. Flares rated X10 or stronger are considered unusually intense.

The classification system for solar flares uses the letters A, B, C, M or X, according to the peak flux in watts per square meters (W / m2) of X-rays with wavelengths 100 to 800 picometers (1 to 8 angstroms), as measured by the GOES spacecraft in the Sun-Earth distance from the Sun of 2.7 × 1017 km.

Classification Approximate peak flux range at 100–800 picometers
(watts / square meter)
ONE <10−7
B 10−7 – 10−6
C 10−6 – 10−5
M 10−5 – 10−4
x > 10−4

The strength of an event within a class is noted with a numeric suffix that goes from 1 up to, but exclusive, 10, which is also the factor of that event in the class. Therefore, an X2 flare is twice as powerful as an X1 flare, an X3 flare is three times as powerful as an X1 and only 50% more powerful than an X2. An X2 is four times stronger than an M5 flare. X-Class flares with a top flux exceeding 10−3 W / m2 may be noted with a numerical suffix equal to or greater than 10.

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