NASA - National Aeronautics and Space Administration

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SDO Logo. Credit: NASA
› View The SDO One Year video April 21, 2011 marks the one-year anniversary of the Solar Dynamics Observatory (SDO) "First Light" press conference. "First light" is the event of a telescope capturing its first images.

Over the past year, the sun has gone from its quietest period in years to the activity marking the beginning of solar cycle 24. SDO has captured every moment with a level of detail never-before possible. The mission has returned unprecedented images of solar flares, eruptions of prominences, and the early stages of coronal mass ejections (CMEs).

Below are some of the most beautiful, interesting, and mesmerizing events seen by SDO during its first year. We would like you to vote for your favorite video from this collection.

This contest will run for two weeks, from Thursday, April 21, 2011 through Thursday May 5, 2011. Check back on May 6 to see which video the public selected as their all-time favorite SDO video from the past year. You may only vote once, so choose carefully!.

#1 - First Light Prominence Soon after the instruments opened their doors, the Sun began performing for SDO with this beautiful prominence eruption. This AIA data is from March 30, 2010, showing a wavelength band that is centered around 304 Å. This extreme ultraviolet emission line is from singly ionized Helium, or He II, and corresponds to a temperature of about 50,000 degrees Celsius.

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#2 - Plasma Rain On April 19, 2010 AIA observed one of the largest prominence eruptions in years. The huge structure erupts, but a great deal of the plasma (hundreds of millions of tons) is unable to escape the gravitational pull of the Sun and falls back down as "plasma rain." As the rain impacts the surface, bright flashes can be seen as the momentum is absorbed on impact. SDO is the first observatory to capture both the rain and the impacts in 304 Å, allowing us to learn a great deal from observations like this.

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#3 - Seven Months This multi-wavelength (211, 193, and 171 Å) movie of the Sun covers seven months of activity (April 25 - Nov. 30, 2011). The frames combine images taken at the same time in three wavelengths of extreme ultraviolet light. The movie shows about 6 frames per day.

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#4 - Swirling Maelstrom Swirling plasma observed in extreme ultraviolet light (304 Å) put on quite a show over 4.5 days (Sept. 18-22, 2010). The twisting strands of plasma, seen in profile over the Sun upper left edge, kept up its dynamic activity the whole period. In addition, four prominence eruptions occurred during the same period. The slight, occasional jumps of the Sun were due to the daily orbital passage of the spacecraft these days behind the Earth for a short period each day. It took the imaging a little time to get back to normal each passage.

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#5 - Merging Sunspots One core area of Sunspot 1117 emerged, and then edged over and merged with another core area over three days (Oct. 25-27, 2010) to form a much larger, active sunspot region. Portions of sunspot groups can shift over time. Each dark umbra (darkest area) in the October 26, 2010 snapshot from the HMI instrument on SDO is as wide as Earth. The magnetic field of this area has been creating a number of small (B- and C-class) solar flares, though no large flares have erupted there to date. Sunspots are cooler, darker areas on the Sun's surface where energy and light are suppressed by intense magnetic forces.

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#6 - Snake Filament Eruption A very long solar filament that had been snaking around the Sun erupted on Dec. 6, 2010 with a flourish. NASA's Solar Dynamics Observatory (SDO) caught the action in dramatic detail in extreme ultraviolet light of Helium, 304 Å. It had been almost a million km long (about half the radius of the Sun) and a prominent feature on the Sun visible over two weeks ago before it rotated out of view. Filaments are elongated clouds of cooler gases suspended above the Sun by magnetic forces. They are rather unstable and often break away from the Sun.

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#7 - Monster Prominence When a rather large-sized (M 3.6 class) flare occurred near the edge of the Sun, it blew out a gorgeous, waving mass of erupting plasma that swirled and twisted over a 90-minute period (Feb. 24, 2011). This event was captured in extreme ultraviolet light at 304 Å. Some of the material blew out into space and other portions fell back to the surface.

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#8 - Valentines Day X2 Flare Active region 1158 let loose with an X2.2 flare at 0153 UT or 8:50 pm ET on February 15, 2011, the largest flare since Dec. 2006 and the biggest flare so far in Solar Cycle 24. This video was taken in the extreme ultraviolet wavelength of 304 Å. A coronal mass ejection was also associated with the flare. The movie shows activity over about two days (Feb. 13-15, 2011).

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#9 - Lotsa Loops As an active region rotated into view, SDO got a good profile look at the constantly changing magnetic field lines arcing high above it (Feb. 23-27, 2011). In extreme ultraviolet light the multitude of lines are revealed because charged particles are spinning along them. The interactions seen here are within an extensive and busy action region. If you watch the clip closely, you can see an eruptive blast (along with a strong flare) from the leading region near the beginning of the clip.

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#10 - Popping All Over With numerous active regions populating the Sun's surface, it is no surprise that over about two days (Mar. 6-8, 2011) SDO saw flares and coronal mass ejections popping off in many directions. The movies were taken in ultraviolet light at 171 Å in temperatures approx. 630,000 degrees Celsius. Besides the many storms, the Sun was alive with arcing loops revealing magnetic field lines interacting above the active regions.

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Artist concept of the SDO spacecraft in orbit. Credit: NASA The Solar Dynamics Observatory (SDO) is the first mission to be launched for NASA's Living With a Star (LWS) Program, a program designed to understand the causes of solar variability and its impacts on Earth. SDO is designed to help us understand the Sun's influence on Earth and Near-Earth space by studying the solar atmosphere on small scales of space and time and in many wavelengths simultaneously.

Most of the videos appearing on this page were received from the Atmospheric Imaging Assembly (AIA) instrument on board SDO. The AIA images the solar atmosphere in multiple wavelengths to link changes in the surface to interior changes, including images of the Sun in 10 wavelengths every 10 seconds.

The Merging Sunspot video came from the Helioseismic and Magnetic Imager (HMI) on board SDO. The HMI instrument is designed to study oscillations and the magnetic field at the solar surface, or photosphere. HMI observes the full solar disk in the Fe I (Iron) absorption line at 6173 angstrom and has a continuous data rate of 55Mbits/second.

One additional instrument on board SDO is the Extreme Ultraviolet Variablity Experiment (EVE), which measures the solar extreme-ultraviolet (EUV) irradiance with unprecedented spectral resolution, temporal cadence, and precision. EVE measures the solar extreme ultraviolet (EUV) spectral irradiance to understand variations on the timescales which influence Earth's climate and near-Earth space.

For more on the SDO mission, visit:

› NASA SDO Mission page

› Goddard SDO project website

› View The SDO One Year video