The Big Foto

SOHO, the Solar & Heliospheric Observatory, is a project of international collaboration between ESA and NASA to study the Sun from its deep core to the outer corona and the solar wind.

SOHO was launched on December 2, 1995. The SOHO spacecraft was built in Europe by an industry team led by prime contractor Matra Marconi Space (now EADS Astrium) under overall management by ESA. The twelve instruments on board SOHO were provided by European and American scientists. Nine of the international instrument consortia are led by European Principal Investigators (PI’s), three by PI’s from the US. Large engineering teams and more than 200 co-investigators from many institutions supported the PI’s in the development of the instruments and in the preparation of their operations and data analysis. NASA was responsible for the launch and is now responsible for mission operations. Large radio dishes around the world which form NASA’s Deep Space Network are used for data downlink and commanding. Mission control is based at Goddard Space Flight Center in Maryland.

1 Twisting prominence. An EIT 304Å image of a large, twirling prominence taken on Jan. 18, 2000. Prominences are huge clouds of relatively cool dense plasma suspended in the Sun's hot, thin corona. At times, they can erupt, escaping the Sun's atmosphere. Credit: SOHO (ESA & NASA) #

2 A comparison of two EIT images almost two years apart illustrates how the level of solar activity has increased significantly. The Sun attains its expected sunspot maximum in the year 2000. These images are captured using Fe IX-X 171 Å emission showing the solar corona at a temperature of about 1.3 million K. Many more sunspots, solar flares, and coronal mass ejections occur during the solar maximum. The numerous active regions and the number/size of magnetic loops in the recent image shows the increase. Credit: SOHO (ESA & NASA) #

3 This composite image presents the three most visible elements of space weather: a storm from the Sun, aurora as seen from space, and aurora as seen from the Earth. The solar storm is a corona mass ejection (CME) composite from EIT 304Å superimposed on a LASCO C2 image, both from SOHO. The middle image from Polar’s VIS imager shows charged particles as they spread down across the U.S. during a large solar storm event on July 14, 2000. Lastly, Jan Curtis took this image of an aurora display in Alaska, the visible evidence of space weather that we see here on Earth. Credit: SOHO (ESA & NASA) #

4 X28 flare in EIT 195 -- The Sun unleashed a powerful flare on 4 November 2003 that could be the most powerful ever witnessed and probably as strong as anything detected since satellites were able to record these events n the mid-1970s. The still and video clip from the Extreme ultraviolet Imager in the 195A emission line captured the event. The two strongest flares on record, in 1989 and 2001, were rated at X20. This one was stronger scientists say. But because it saturated the X-ray detector aboard NOAA's GOES satellite that monitors the Sun, it is not possible to tell exactly how large it was. The consensus by scientists put it somewhere around X28. Credit: SOHO (ESA & NASA) #

5 CME blast and subsequent impact at Earth -- This illustration shows a CME blasting off the Sun’s surface in the direction of Ea CME blast and subsequent impact at Earth -- This illustration shows a CME blasting off the Sun’s surface in the direction of Earth. This left portion is composed of an EIT 304 image superimposed on a LASCO C2 coronagraph. Two to four days later, the CME cloud is shown striking and beginning to be mostly deflected around the Earth’s magnetosphere. The blue paths emanating from the Earth’s poles represent some of its magnetic field lines. The magnetic cloud of plasma can extend to 30 million miles wide by the time it reaches earth. These storms, which occur frequently, can disrupt communications and navigational equipment, damage satellites, and even cause blackouts. (Objects in the illustration are not drawn to scale.) Credit: SOHO (ESA & NASA) #