Timeline of X-class flares from active region AR3664
A huge cluster of sunspots known as active region AR3664 spent almost a full month producing massive solar flares, highly energetic particles, and large bubbles of plasma known as coronal mass ejections. This timeline shows the X-class solar flares detected on the Sun’s side facing Earth, and by Solar Orbiter watching the Sun's other side.
In the weekend of 10–12 May, AR3664 was responsible for the biggest solar storm to hit Earth in over 20 years, and in the following days it produced more massive flares which caused large radio blackouts.
But that's not all: in the days that the active region was hidden from Earth's view, Solar Orbiter saw it produce more powerful flares, accompanied by high-energy particles and massive coronal mass ejections. On 20 May AR3664 produced the largest solar flare yet, with an estimated class of X12.
Solar Orbiter's measurements served as a warning for more solar activity to come. In the week of 27 May, AR3664 produced several more X-class flares, including two within the span of 12 hours.
[Image description: Timeline of solar flares from active region AR3664, with dates from 9 May to 2 June 2024 indicated along a horizontal arrow at the bottom. Each flare is indicated by a circle (blue for those seen from Earth, red for those seen by Solar Orbiter on the Sun's opposite side) with a number indicating the flare's intensity (in some cases rounded to the nearest decimal point).]
