Sun bursts are sudden releases of energy from the sun's atmosphere, known as the corona. Although the bursts are not visible to the naked eye, they represent tremendous amounts of power, and they can have an impact on Earth and more distant planets as the energy travels through the solar system. During periods of increased solar activity, sun bursts can become severe enough to disable satellites and other equipment, as humans have learned to their chagrin.
Changes in the sun's level of activity are caused by the sun's rotation. Like other bodies in space, the sun moves, and as it does, it creates a solar cycle which is caused by rotational forces along the surface of the sun. Sun bursts typically start with sunspots, dark areas which appear on the sun when the cooler inner core of the sun is temporarily exposed by the shifting corona. When sunspots start to spread, it can signal an expected increase in solar activity.
Solar flares, another type of sun burst, occur when the corona releases huge amounts of energy in the fraction of a second, causing a bright spot to appear. Solar flares often occur around sunspots, although they also occur inside the corona, where they cannot be confirmed with visual observations. A big solar flare can release enough energy to interfere with communications on Earth, as the electromagnetic energy from the sun interacts with Earth-bound communications systems and satellites.
In a radical form of sun burst called a coronal mass ejection (CME), the sun pushes out huge flares of plasma. These plasma flares can push against the Earth's atmosphere, causing especially bright, prolonged, and brilliant auroras, and they also increase radiation levels in space substantially. CMEs are one of the reasons that space travel is potentially very dangerous, as the increased radiation level could pose a risk to living organisms in spacecraft.
Scientists can use the ebb and flow of sun bursts to track the sun's cycles, and to gather more information about how the sun works. The activities observed in the sun are also known to occur in other stars, even though researchers cannot usually see them in action because of the great distances involved. Understanding patterns of sun bursts is important to the business community as well as the scientific community, because sun bursts can interrupt satellite launches, the flight of spacecraft, and many other human activities, sometimes with devastating effects.
By Mary McMahon
Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All The Science researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.