The sun's rotation produces changes in its magnetic field, which flips completely every 11 years or so, triggering a phase of intense activity. Solar flares—huge eruptions from the surface of the sun lasting minutes or ...
Astronomy
May 16, 2023
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Southwest Research Institute (SwRI) scientists observed the first close-ups of a source of energetic particles expelled from the sun, viewing them from just half an astronomical unit (AU), or about 46.5 million miles. The ...
Astronomy
May 15, 2023
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Solar flares and coronal mass ejections (CME) are two of the most energetic processes in the solar system, showering the Earth's magnetic field with billions of tons of highly energetic plasma gas, potentially disrupting ...
Astronomy
May 10, 2023
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For a new study, a team of physicists recruited roughly 1,000 undergraduate students at the University of Colorado Boulder to help answer one of the most enduring questions about the sun: How does the star's outermost atmosphere, ...
Astronomy
May 9, 2023
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ESA's wind mission, Aeolus, will soon be lowered in orbit leading to its fiery reentry and burn-up through Earth's atmosphere. ESA's efforts to ensure a safe return go well beyond international standards and place the agency ...
Space Exploration
May 8, 2023
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A team of Japanese astronomers used simultaneous ground-based and space-based observations to capture a more complete picture of a superflare on a star. The observed flare started with a very massive, high-velocity prominence ...
Astronomy
Apr 28, 2023
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An old NASA satellite that studied the sun for more than a decade fell to Earth over the Sahara Desert, the space agency reported Thursday.
Space Exploration
Apr 20, 2023
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An old NASA satellite is expected to fall to Earth this week, but experts tracking the spacecraft say chances are low it will pose any danger.
Space Exploration
Apr 18, 2023
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Simulating solar flares on a scale the size of a banana, researchers at Caltech have parsed out the process by which these massive explosions blast potentially harmful energetic particles and X-rays into the cosmos. Their ...
Astronomy
Apr 6, 2023
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As questions abound about the Earth's closest star, scientists are seeking answers critical to forecasting solar flares that threaten satellites and other electronics.
Astronomy
Mar 30, 2023
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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
