Related topics: magnetic field · earth · sun · nasa · space weather

New sunspots potentially herald increased solar activity

On May 29, 2020, a family of sunspots—dark spots that freckle the face of the sun, representing areas of complex magnetic fields—sported the biggest solar flare since October 2017. Although the sunspots are not yet visible ...

The Sun is less active magnetically than other stars

Our sun is the source of life on Earth. Its calm glow across billions of years has allowed life to evolve and flourish. This does not mean the sun doesn't have an active side. We have observed massive solar flares, such as ...

Fast reconnection in turbulent media

Solar flares, similar to many other astrophysical energetic processes, are related to magnetic reconnection. During these events magnetic energy is transferred from other forms of energy, mostly heat and energetic particles. ...

Using big data to combat catastrophes

In March 1989, a tripped circuit in the Hydro-Québec power grid left 6 million people without electricity. A week earlier, an unusually harsh snowstorm had strained the region; the day before, a solar flare and accompanying ...

Researchers find clues to how hazardous space radiation begins

Scientists at the University of New Hampshire have unlocked one of the mysteries of how particles from flares on the sun accumulate at early stages in the energization of hazardous radiation that is harmful to astronauts, ...

Image: The sun in 2019

The changing activity of our sun as seen by ESA's Proba-2 satellite in 2019.

Video: ESA's short film, 'The Burn'

ESA's short film, The Burn, takes us into the heart of Europe's mission control during a critical moment in the life of a future mission.

Detecting solar flares, more in real time

Computers can learn to find solar flares and other events in vast streams of solar images and help NOAA forecasters issue timely alerts, according to a new study. The machine-learning technique, developed by scientists at ...

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Solar flare

A solar flare is a big explosion in the Sun's atmosphere that can release as much as 6 × 1025 joules of energy. The term is also used to refer to similar phenomena in other stars, where the more accurate term stellar flare applies.

Solar flares affect all layers of the solar atmosphere (photosphere, corona, and chromosphere), heating plasma to tens of millions of kelvins and accelerating electrons, protons, and heavier ions to near the speed of light. They produce radiation across the electromagnetic spectrum at all wavelengths, from radio waves to gamma rays. Most flares occur in active regions around sunspots, where intense magnetic fields penetrate the photosphere to link the corona to the solar interior. Flares are powered by the sudden (timescales of minutes to tens of minutes) release of magnetic energy stored in the corona. If a solar flare is exceptionally powerful, it can cause coronal mass ejections.

X-rays and UV radiation emitted by solar flares can affect Earth's ionosphere and disrupt long-range radio communications. Direct radio emission at decimetric wavelengths may disturb operation of radars and other devices operating at these frequencies.

Solar flares were first observed on the Sun by Richard Christopher Carrington and independently by Richard Hodgson in 1859 as localized visible brightenings of small areas within a sunspot group. Stellar flares have also been observed on a variety of other stars.

The frequency of occurrence of solar flares varies, from several per day when the Sun is particularly "active" to less than one each week when the Sun is "quiet". Large flares are less frequent than smaller ones. Solar activity varies with an 11-year cycle (the solar cycle). At the peak of the cycle there are typically more sunspots on the Sun, and hence more solar flares.

This text uses material from Wikipedia, licensed under CC BY-SA