The Sun All images and information courtesy of SOHO consortium. SOHO is a project of international cooperation between ESA and NASA."

Our sun

This collage of images taken in the 284 Angstrom wavelength of extreme ultraviolet light shows the Sun as it changed through almost two complete solar cycles. A solar activity cycle lasts 11 years on average. During a solar cycle the number of sunspots and level of solar activity dramatically rise and fall in a bell-shaped curve. The change is being driven by the gradual reversal of the Sun's magnetic field during that 11-year cycle. The brighter areas in the extreme ultraviolet correspond to areas of strong magnetic field. The remarkable record of long-term observations by SOHO has significantly advanced our understanding of the Sun's processes.

Solar Corona

Solar Corona Magnetic Loops SOHO-EIT image in resonance lines of eight and nine times ionized iron (Fe IX/X) at 171 Angstroms in the extreme ultraviolet showing the solar corona at a temperature of about 1 million K. Solar Corona Magnetic Loops "Courtesy of SOHO/[instrument] consortium. SOHO is a project of international cooperation between ESA and NASA."

Sunspots

Sunspots

Prominences Prominences are large clouds of relatively cool, dense plasma suspended in the Sun's hot, tenuous corona. Magnetic fields built up enormous forces that propelled particles out beyond the Sun's surface. The one on the right and possibly both were associated with a flare and a coronal mass ejection that blasted away from the Sun at about the time of this image. The twisting nature of the one on the right is of particular interest to some solar physicists who believe that eruptive events like this are the Sun's way of getting rid of magnetic fields that are twisted up too tightly, like the rubber bands that run model airplanes. For a sense of scale, the prominences extend about 20 Earths out from the Sun. They both had disappeared by the time the next image was taken 6 hours later.

The Sun’s magnetic field and releases of plasma directly affect Earth and the rest of the solar system. Solar wind shapes the Earth’s magnetosphere and magnetic storms are illustrated here as approaching Earth. These storms, which occur frequently, can disrupt communications and navigational equipment, damage satellites, and even cause blackouts. The white lines represent the solar wind; the purple line is the bow shock line; and the blue lines surrounding the Earth represent its protective magnetosphere. The magnetic cloud of plasma can extend to 30 million miles wide by the time it reaches earth.

A close-up of an erupting prominence with Earth inset at the approximate scale of the image. Taken on July 1, 2002 in 304A emission. The 304A filter shows emission from singly ionized helium at about 60000 degrees C.

Coronal Mass Ejection (CME)

Coronal Mass Ejection (CME)

A comparison of three images over four years apart illustrates how the level of solar activity has risen from near minimum to near maximum in the Sun's 11-years solar cycle. These images are captured using He II 304  emissions showing the solar corona at a temperature of about 60,000 degrees K. Many more sunspots, solar flares, and coronal mass ejections occur during the solar maximum. The increase in activity can be seen in the number of white areas, i.e., indicators of strong magnetic intensity .