April 22, 2013
Three Years With SDO
Lee Rannals for redOrbit.com — Your Universe Online
The spacecraft's Atmospheric Imaging Assembly snaps a shot of the sun every twelve seconds in ten different wavelengths. The latest video shows the past three years of the sun at a pace of two images per day.
[ Watch the Video: Three Years With Solar Dynamics Observatory ]
The video, released by NASA, is a collection of images based on wavelength 171 angstroms, which is in the extreme ultraviolet range and shows solar material at around about 1.08 million Fahrenheit. This wavelength allows scientists to see the sun's 25-day rotation, as well as how the solar activity has increased for the past three years. Currently, the sun is at its peak in its regular 11-year cycle, a stage known as the Solar Maximum.
During the new video, the sun increases and decreases in size because of the varying distance between the spacecraft and sun.
"The image is, however, remarkably consistent and stable despite the fact SDO orbits Earth at 6,876 mph and Earth orbits the sun at 67,062 mph," NASA said. "Such stability is crucial for scientists, who use SDO to learn more about our closest star."
NASA said these images have regularly caught solar flares and coronal mass ejections in the act. These events create space weather, sending radiation and solar material toward Earth. Space weather can potentially cause disruptions with Earth satellites and the astronauts aboard the International Space Station.
"SDO´s glimpses into the violent dance on the sun help scientists understand what causes these giant explosions -- with the hopes of some day improving our ability to predict this space weather," the space agency said.
So far, the solar activity on the sun has been considerably low this year. Scientists believe this lower-than-expected solar activity means the current solar cycle will have two peaks.
“This is solar maximum, but it looks different from what we expected because it is double peaked,” Dean Pesnell, a solar physicist at the Goddard Space Flight Center, explained in a statement. “Conventional wisdom holds that solar activity swings back and forth like a simple pendulum. At one end of the cycle, there is a quiet time with few sunspots and flares. At the other end, Solar Max brings high sunspot numbers and solar storms. It´s a regular rhythm that repeats every 11 years.”
He said the last two solar maximums, in 1989 and 2001, had two peaks. During those periods, there was an increase in solar activity, then a decrease, and then another increase.
SDO recorded three coronal mass ejections over the course of the weekend on the sun. These events were not directed towards Earth and are not expected to disrupt satellites or any other activity.