Sigmoids Predict Solar Eruptions
16.03.1999

On the Sun, S marks the spot. Solar explosions have been discovered to explode preferentially from regions marked with this letter. The surface of the quiet Sun is a maze of hot gas and flowing magnetic fields. When two regions of high magnetic field strength approach each other, they typically pass uneventfully.

Spicules: Jets on the Sun
2.11.2008

Imagine a pipe as wide as a state and as long as half the Earth. Now imagine that this pipe is filled with hot gas moving 50,000 kilometers per hour. Further imagine that this pipe is not made of metal but a transparent magnetic field.

Solar Shock Wave
30.04.1999

On September 24, 1997 a shock wave blasted across the surface of the sun at speeds of 250 to 600 kilometers per second. On planet Earth, observer Barry Reynolds photographed the expanding shock front (left) in the light emitted by hydrogen atoms at the solar surface.

Solar Surfin
16.07.1999

The sun's corona is a tenuous outer atmosphere composed of streams of energetic charged particles, but it is only easily seen from Earth during a total solar eclipse. For example, this 1991 image of totality from atop Mauna Kea, Hawaii forms a fleeting snapshot of the mysterious corona's beautiful, intricate structures and streams.

Hole in the Sun
27.09.2007

The dark expanse below the equator of the Sun is a coronal hole -- a low density region extending above the surface where the solar magnetic field opens freely into interplanetary space. Shown in false color, the picture was recorded on September 19th in extreme ultraviolet light by the EIT instrument onboard the space-based SOHO observatory.

The Iron Sun
29.09.2001

The ultraviolet light emitted by eleven times ionized iron at temperatures over 2 million degrees Farenheit was used to record the above picture of the Sun on September 22, the date of the autumnal equinox.

Movie: Analemma Over New Jersey
4.12.2007

An analemma is that figure-8 curve that you get when you mark the position of the Sun at the same time each day throughout planet Earth's year. Above, 26 separate exposures were recorded to illustrate the regular solar motion -- a difficult project performed mostly during the calendar year 2006.

Follow The Spots
21.10.1999

The Sun rotates on its axis about once every 27 days. How can you tell? Just follow the sunspots. This composite picture was constructed from solar images recorded daily by the MDI instrument on board the space-based SOlar and Heliospheric Observatory (SOHO).

Perihelion Sun
11.01.1999

The Earth's orbit is not a perfect, sun-centered circle. At aphelion, the most distant point in Earth's orbit, the Sun is 150 million kilometers away and at perihelion, the closest point, Earth approaches the Sun to within about 147 million kilometers. While aphelion occurs in July, perihelion for planet Earth comes in January.

SOHO Composite: Coronal Mass Ejection
20.08.1998

This complex composite image of an ominous and spectacular event - an expanding storm of energetic particles from the Sun - was constructed using data recorded by the SOHO spacecraft on November 6, 1997. Four images...