Schematic view of the inner structure of the Sun
Click on image for full size
The Sun and the Solar Atmosphere
What are the "parts" of the Sun? The photosphere is the visible "surface"
of the Sun. The three regions of the solar interior are the core, the radiative zone, and the uppermost convective zone. The solar atmosphere includes the chromosphere and the corona. The Sun's atmosphere, in
the form of the solar wind and the Interplanetary Magnetic Field (IMF), extends
outward into interplanetary space. In a sense, the Sun's atmosphere actually
fills the heliosphere, the vast "bubble" in space extending well
What features and events can we see on the Sun? Regions of intertwined magnetic fields form in the solar interior and give rise to active regions, sunspots, and
coronal holes at the Sun's visible surface. Fountains of electrified plasma shoot forth from the photosphere and give rise to prominences, helmet streamers, and spicules. Tremendous explosions on the Sun, solar flares and Coronal Mass
Ejections (CME), hurl radiation and energized subatomic particles outward into
The solar wind is an extension of the Sun's atmosphere into
space. This supersonic flow of plasma carries matter and energy outward. The IMF, embedded
within the solar wind, carries the Sun's magnetic force
field outward through the Solar System. Interactions between the solar wind
and the magnetospheres, atmospheres, and sometimes the surfaces of planets affect the evolution of planets and their atmospheres.
The Sun changes over time. Vast explosions, flares and CMEs, alter the Sun's radiation and solar wind over time scales from minutes to hours to days. The 11-year sunspot cycle spans a much longer time scale. Studies of Sun-like stars of various ages have helped us learn about our Sun's wild youth and the changes in activity to expect throughout a star's lifetime.
Shop Windows to the Universe Science Store!
Our online store
includes issues of NESTA's quarterly journal, The Earth Scientist
, full of classroom activities on different topics in Earth and space science, as well as books
on science education!
You might also be interested in:
Most of the energy we receive from the Sun is the visible (white) light emitted from the photosphere. The photosphere is one of the coolest regions of the Sun (6000 K), so only a small fraction (0.1%)...more
The solar core is made up of a really hot and dense gas (in the plasma state). The temperature of 15 million kelvins (27 million degrees Faranheit) keeps the core at a gaseous state. The core is where...more
Rising above the Sun's chromosphere , the temperature jumps sharply from a few tens of thousands of kelvins to as much as a few million kelvins in the Sun's outer atmosphere, the solar corona. Understanding...more
The Sun has a very large and very complex magnetic field. The magnetic field at an average place on the Sun is around 1 Gauss, about twice as strong as the average field on the surface of Earth (around...more
An active region on the Sun is an area with an especially strong magnetic field. Sunspots frequently form in active regions. Active regions appear bright in X-ray and ultraviolet images. Solar activity,...more
Sunspots are dark, planet-sized regions that appear on the "surface" of the Sun. Sunspots are "dark" because they are colder than the areas around them. A large sunspot might have a temperature of about...more
Plasma is known as the fourth state of matter. The other three states are solid, liquid and gas.In most cases, matter on Earth has electrons that orbit around the atom's nucleus. The negatively charged...more