Solar Science

The sun is a dynamic star, made of super-hot ionized gas called plasma. The sun's surface and atmosphere change continually, driven by the magnetic forces generated by this constantly-moving plasma. The sun releases energy in two ways: the usual flow of light that illuminates the Earth and makes life possible; but also in more violent and dramatic ways--it gives off bursts of light, particles, and magnetic fields that can have ripple effects all the way out to the solar system's magnetic edge. We study the sun to better understand how its ever-changing conditions can influence Earth, other worlds, and even space itself.

NASA studies the sun for numerous reasons. For one thing, its influence on the habitability of Earth is incredibly complex, providing radiation that depending on the amount can be either a boon or hazard to the development of life. Second, this radiation, and the accompanying energy and magnetic fields that the sun sends out -- is intense and dynamic, with the ability to create changes in the space weather around us, and interfere with our space technology and communications systems. Finally, we study this star we live with, because it's the only star we can study up close. Studying our sun informs research about other stars throughout the universe.

The sun's activity and conditions vary on almost every timescale, from tiny changes that happen over milliseconds, to solar eruptions that last hours or days, to its 27-day rotation. The solar magnetic field cycles through a complete change in direction and back about every 22 years, which in turn gives rise to the roughly 11-year cycle in solar activity. As magnetic field becomes more complex, it releases energy near the solar surface. These solar explosions can take the form of solar flares, coronal mass ejections, or releases of incredibly fast charged particles that race out from the sun at nearly the speed of light.

NASA watches the sun nearly 24-seven with a fleet of solar observatories, studying everything from the sun's tenuous outer atmosphere, to its roiling surface, and even peering inside the sun using magnetic and helioseismic instruments.

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Solar activity follows a roughly 11-year cycle. This composite image shows the sun in extreme ultraviolet wavelengths about once a year over the course of a complete solar cycle. This type of light is typically invisible to our eyes, but is colorized here in green. As the solar cycle slopes towards solar minimum, the bright active regions, often accompanied by dark sunspots on the visible-light sun, become fewer and smaller. Active regions are the source of most of the sun's outbursts, meaning that solar activity and number of active regions decline together. As the activity cycle picks back up, these bright active regions cover more and more of the sun's face, while solar activity becomes more and more frequent.
Credit: ESA/NASA/SOHO

The Sun

The sun is a dynamic star, made of super-hot ionized gas called plasma.

The sun's surface and atmosphere change continually, driven by the magnetic forces generated by this constantly-moving plasma. The sun releases energy in two ways: the usual flow of light that illuminates the Earth and makes life possible; but also in more violent and dramatic ways--it gives off bursts of light, particles, and magnetic fields that can have ripple effects all the way out to the solar system's magnetic edge.

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Solar activity follows a roughly 11-year cycle. This composite image shows the sun in extreme ultraviolet wavelengths about once a year over the course of a complete solar cycle.
ESA/NASA/SOHO

Magnetospheres

A magnetosphere is the region around a planet dominated by the planet's magnetic field.

Other planets in our solar system have magnetospheres, but Earth has the strongest one of all the rocky planets: Earth's magnetosphere is a vast, comet-shaped bubble, which has played a crucial role in our planet's habitability. Life on Earth initially developed and continues to be sustained under the protection of this magnetic environment.

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Earth is surrounded by a giant magnetic bubble called the magnetosphere, which is is part of a dynamic, interconnected system that responds to solar, planetary, and interstellar conditions.
NASA

Space Weather

Though space is about a thousand times emptier than even the best laboratory vacuums on Earth, it’s not completely devoid of matter.

The sun’s constant outflow of solar wind fills space with a thin and tenuous wash of particles, fields, and plasma. This solar wind, along with other solar events like giant explosions called coronal mass ejections, influences the very nature of space and can interact with the magnetic systems of Earth and other worlds. Such effects also change the radiation environment through which our spacecraft – and, one day, our astronauts headed to Mars – travel. 

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