Photo worth seeing: Radiation burst on the sun

Photo worth seeing: Radiation burst on the sun
This image from NASA’s Solar Dynamics Observatory shows a strong burst of radiation on the Sun in the extreme ultraviolet. © NASA/SDO

Our sun is currently in a very active phase of its cycle. It has repeatedly produced strong radiation bursts in recent weeks, this one occurred on February 17, 2023.

The sun is actually a rather quiet star, but it is by no means inactive: active sunspots repeatedly cause bursts of radiation and plasma eruptions that release high-energy particles and radiation. If such a flare or mass ejection goes towards Earth, this can have serious consequences. Because the high-energy charged particles of the solar storms and their radiation can disrupt radio communication, cause blackouts in power grids and paralyze satellites.

Partly because of this, NASA and other space agencies have today deployed numerous observatories in space whose sole purpose is to closely monitor the sun around the clock. This is particularly important in times of strong solar activity, when our star is approaching a maximum in its activity cycle, which fluctuates every eleven years. The sun is currently becoming more active again after its last minimum in December 2019. It shows a particularly large number of sunspots and strong bursts of radiation. It is expected to reach its maximum in the current cycle in 2025.

This image of the Solar Dynamics Observatory (SDO) from February 17, 2023 shows a strong burst of radiation, a so-called X-flare, at the upper left edge of the sun. It thus belongs to the most intense class of solar radiation bursts. They are divided into five classes – A, B, C, M and X – according to their strength. Each of these classes is ten times stronger than the previous one. Within the classes, numbers from 1 to 9 indicate a further subdivision. The flare shown here is an X2.2 and thus one of the strongest of this solar cycle.

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