Solar flare

The sun has big flashes.

These are called solar flares. They happen in the sun's air.

Flares happen when energy is released. This energy moves tiny bits of matter. These bits move very fast.

Flares can be small or very large. Some flares happen every day. Other flares happen only once a week.

The light from a flare travels to Earth. It hits the top of our air. This can change how our radios work.

Flares also happen on other stars. Scientists study them to learn more.

A solar flare is a bright flash in the Sun's atmosphere.

These flares happen in active areas. These areas often have sunspots.

Flares happen because of magnetic energy. This energy is stored in the Sun's atmosphere. Sometimes, magnetic lines of force reconnect. This means they snap and join in new ways. This snap lets out a lot of power. This power makes tiny parts of matter move very fast. These parts move at nearly the speed of light.

Flares come in different sizes. Scientists use letters to name them. They use A, B, C, M, and X. X-class flares are the most extreme.

The number after the letter shows the strength. An X2 flare is twice as strong as an X1.

Flares send out light called radiation. This light travels to Earth very fast. It hits our ionosphere. The ionosphere is the upper part of our air.

This can change how radio works. It can also change how GPS works. Some flares might even slow down satellites.

A solar flare is a sudden, bright burst of energy in the Sun's atmosphere.

These flares happen in active regions where magnetic fields are very strong. They release electromagnetic radiation, which is a type of energy that travels as waves. This radiation can include everything from radio waves to gamma rays. Flares affect every layer of the Sun, including the photosphere, the chromosphere, and the corona. Sometimes, these flares are joined by coronal mass ejections, which are huge clouds of solar material.

How do these massive bursts happen? It all starts with stored magnetic energy in the Sun's atmosphere. Scientists believe a process called magnetic reconnection causes the flare. This happens when magnetic lines of force snap and join in new ways. This sudden snap releases energy that pushes charged particles, like electrons and protons, to move incredibly fast. Some particles even reach near the speed of light. This energy release can also create flare sprays that move at 20 to 2,000 kilometres per second.

Scientists use a specific system to name the strength of these flares. They use the letters A, B, C, M, and X. The letters are based on how much X-ray energy the flare puts out. An X-class flare is the most extreme type of event.

You can also add a number to the letter to show more detail. For example, an X2 flare is twice as strong as an X1 flare. An M-class flare is ten times smaller than an X-class flare with the same number. This system was first made in 1970 using only C, M, and X classes.

Solar flares do not happen at the same rate all the time. Their frequency changes with the 11-year solar cycle. During solar maxima, there might be several flares every single day. During solar minima, there might be less than one flare every week. In 1984, Erich Rieger and his team found a special 154-day pattern in gamma-ray flares. This is now called the Rieger period. While X-class flares are rare, they are very powerful. On average, severe X10-class flares only happen about eight times in one 11-year cycle.

Even though the Sun is far away, its flares can affect our technology on Earth. The X-ray and ultraviolet radiation from a flare hits the Earth's upper atmosphere. This layer of air is called the ionosphere.

The radiation can increase the ionization in this layer. This change can interfere with short-wave radio signals and GPS systems. It can even cause the upper atmosphere to expand. This expansion creates extra drag on satellites in low Earth orbit. This drag can cause a satellite's orbit to decay over time.

A solar flare is an intense, localized burst of electromagnetic radiation. This energy release happens within the Sun's atmosphere. These eruptions occur in active regions where magnetic fields are very strong. Often, flares are accompanied by other events like coronal mass ejections or solar particle events. They affect all layers of the solar atmosphere, including the photosphere, chromosphere, and corona.

Solar flares are not unique to our Sun. They also occur on other stars, where they are called stellar flares.

The mechanism behind a flare involves the release of stored magnetic energy. Scientists believe a process called magnetic reconnection causes this. This likely happens on solar arcades, which are series of coronal loops. These loops follow magnetic lines of force. During reconnection, these lines snap and join into new, lower loops. This sudden change releases massive amounts of energy. This energy accelerates charged particles, such as electrons and protons, in the surrounding plasma. Some particles reach near the speed of light.

These emissions typically follow three identifiable stages. First, there is a precursor phase. Next comes the impulsive phase, where particle acceleration is the main driver. Finally, a gradual phase occurs. In this stage, hot plasma injected into the corona cools down. It cools through radiation and by conducting energy back to the lower atmosphere. Some flares also show an extreme ultraviolet (EUV) late phase. This specific phase is currently unexplained by scientists.

Scientists classify solar flares using a specific system. This system is based on the peak flux of soft X-rays. The letters used are A, B, C, M, and X. These letters represent different ranges of watts per square metre (W/m2). An X-class flare is the most powerful, while an A-class is the weakest.

You can add a number to the letter to show intensity. An X2 flare is twice as strong as an X1 flare. This system was created in 1970 using only C, M, and X. The A and B classes were added later in the 1990s.

The frequency of these events changes over time. This variation follows the 11-year solar cycle. During solar maxima, there may be several flares per day. During solar minima, there may be fewer than one per week. Powerful flares are much less common than weaker ones. For example, M1-class flares occur about 2,000 times per cycle. However, X10-class flares occur only about eight times per cycle.

In 1984, Erich Rieger discovered a 154-day period in gamma-ray flares. This is now known as the Rieger period.

Solar flares can have significant effects on Earth. The X-ray and extreme ultraviolet (XUV) radiation hits our upper atmosphere. This layer is known as the ionosphere.

This radiation causes photoionization, which frees electrons in the atmosphere. This process can create sudden ionospheric disturbances. These disturbances can interfere with short-wave radio communication. They can also disrupt global navigation satellite systems (GNSS), such as GPS. Furthermore, the heated atmosphere expands. This expansion increases drag on satellites in low Earth orbit. This drag can cause their orbits to decay over time.

After a flare, new structures can form in the Sun's atmosphere. These are called post-eruption loops. They are made of hot plasma and form across the neutral line. These loops extend from the photosphere up into the corona. In powerful flares, these loops may form a post-eruption arcade. These large, arch-like structures can last for hours or even days.

These events show how deeply connected magnetic energy is to the entire solar system.