A long filament erupted on the sun on August 31, 2012, shown here in a movie captured by NASA’s Solar Dynamics Observatory (SDO) from noon EDT to 1:45 a.m. the next morning.
The filament lies in the lower left corner of the sun. The movie shows light at 304 Angstroms and 171 Angstroms, both of which help scientists observe the sun’s atmosphere, or corona. Credit: NASA/SDO/AIA
Credit: NASA
On August 31, 2012 a long filament of solar material that had been hovering in the sun’s atmosphere, the corona, erupted out into space at 4:36 p.m. EDT. The coronal mass ejection, or CME, traveled at over 900 miles per second. The CME did not travel directly toward Earth, but did connect with Earth’s magnetic environment, or magnetosphere, with a glancing blow. causing aurora to appear on the night of Monday, September 3.
Swirls of green and red appear in an aurora over Whitehorse, Yukon on the night of September 3, 2012. The aurora was due to the interaction of a coronal mass ejection (CME) from the sun with Earth’s magnetosphere. The CME left the sun on August 31 and arrived on September 3. Image Courtesy of David Cartier, Sr.
Four images of a filament on the sun from August 31, 2012 are shown here in various wavelengths of light as captured by NASA’s Solar Dynamics Observatory (SDO). Starting from the upper left and going clockwise they represent light in the: 335, 171, 304 and 131 Angstrom wavelengths. Since each wavelength of light generally corresponds to solar material at a particular temperature, scientists can compare images like this to observe how the material moves during an eruption. › View larger Credit: NASA/SDO/AIA/GSFC
A solar prominence (also known as a filament when viewed against the solar disk) is a large, bright feature extending outward from the Sun’s surface. Prominences are anchored to the Sun’s surface in the photosphere, and extend outwards into the Sun’s hot outer atmosphere, called the corona. A prominence forms over timescales of about a day, and stable prominences may persist in the corona for several months, looping hundreds of thousands of miles into space. Scientists are still researching how and why prominences are formed.
The red-glowing looped material is plasma, a hot gas comprised of electrically charged hydrogen and helium. The prominence plasma flows along a tangled and twisted structure of magnetic fields generated by the sun’s internal dynamo. An erupting prominence occurs when such a structure becomes unstable and bursts outward, releasing the plasma.
Swirls of green and red appear in an aurora over Whitehorse, Yukon on the night of September 3, 2012. The aurora was due to the interaction of a coronal mass ejection (CME) from the sun with Earth’s magnetosphere. The CME left the sun on August 31 and arrived on September 3.
The image gives a basic overview of the Sun’s parts. The cut-out shows the three major interior zones: the core (where energy is generated by nuclear reactions), the radiative zone (where energy travels outward by radiation through about 70% of the Sun), and the convection zone (where convection currents circulate the Sun’s energy to the surface). The surface features (flare, sunspots and photosphere, chromosphere, and the prominence) are all clipped from actual SOHO images of the Sun.
Credit: NASA/SOHO
The Sun is a magnetic variable star at the center of our solar system that drives the space environment of the planets, including the Earth. The distance of the Sun from the Earth is approximately 93 million miles. At this distance, light travels from the Sun to Earth in about 8 minutes and 19 seconds. The Sun has a diameter of about 865,000 miles, about 109 times that of Earth. Its mass, about 330,000 times that of Earth, accounts for about 99.86% of the total mass of the Solar System. About three quarters of the Sun’s mass consists of hydrogen, while the rest is mostly helium. Less than 2% consists of heavier elements, including oxygen, carbon, neon, iron, and others. The Sun is neither a solid nor a gas but is actually plasma. This plasma is tenuous and gaseous near the surface, but gets denser down towards the Sun’s fusion core.
The Sun, as shown by the illustration at right, can be divided into six layers. From the center out, the layers of the Sun are as follows: the solar interior composed of the core (which occupies the innermost quarter or so of the Sun’s radius), the radiative zone, and the convective zone, then there is the visible surface known as the photosphere, the chromosphere, and finally the outermost layer, the corona. The energy produced through fusion in the Sun’s core powers the Sun and produces all of the heat and light that we receive here on Earth.
The Sun, like most stars, is a main sequence star, and thus generates its energy by nuclear fusion of hydrogen nuclei into helium. In its core, the Sun fuses 430–600 million tons of hydrogen each second. The Sun’s hot corona continuously expands in space creating the solar wind, a stream of charged particles that extends to the heliopause at roughly 100 astronomical units. The bubble in the interstellar medium formed by the solar wind, the heliosphere, is the largest continuous structure in the Solar System.
Stars like our Sun shine for nine to ten billion years. The Sun is about 4.5 billion years old, judging by the age of moon rocks. Based on this information, current astrophysical theory predicts that the Sun will become a red giant in about five billion (5,000,000,000) years.
› View larger Credit: NASA/SDO/AIA/GSFC 
› View larger Image Courtesy of David Cartier, Sr. 
