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

The U.S. Postal Service to issue NASA sun science forever stamps

NASA's images of the sun's dynamic and dazzling beauty have captivated the attention of millions. In 2021, the US Postal Service is showcasing the sun's many faces with a series of sun Science forever stamps that show images ...

Image: The sun in 2020

These 366 images of the sun were made by ESA's Proba-2 satellite in 2020.

Chance played a major role in keeping Earth fit for life

A study by the University of Southampton gives a new perspective on why our planet has managed to stay habitable for billions of years—concluding it is almost certainly due, at least in part, to luck. The research suggests ...

Artificial intelligence sets sights on the sun

Scientists from the University of Graz and the Kanzelhöhe Solar Observatory (Austria) and their colleagues from the Skolkovo Institute of Science and Technology (Skoltech) developed a new method based on deep learning for ...

Aluminum alloy research could benefit manned space missions

The MIAMI-2—Microscopes and Ion Accelerators for Materials Investigations—facility has helped Dr. Matheus Tunes investigate a new alloy that will harden aluminum without increasing its weight significantly.

A new look at sunspots

NASA's extensive fleet of spacecraft allows scientists to study the Sun extremely close-up—one of the agency's spacecraft is even on its way to fly through the Sun's outer atmosphere. But sometimes taking a step back can ...

Solar cycle 25 has begun

In the past one and a half years, the sun has been rather dull: hardly a sunspot covered its surface, hardly a solar flare hurled radiation and particles into space. As observational data now show, for the last nine months ...

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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