First Ever STEREO Images of the Entire Sun
On Feb. 6th, NASA's twin STEREO probes moved into position on opposite sides of the sun, and they are now beaming back uninterrupted images of the entire star—front and back.
February 6, 2011: It's official: The sun is a sphere.
On Feb. 6th, NASA's twin STEREO probes moved into position on opposite
sides of the sun, and they are now beaming back uninterrupted images of
the entire star—front and back.
"For the first time ever, we can watch solar activity in its full
3-dimensional glory," says Angelos Vourlidas, a member of the STEREO
science team at the Naval Research Lab in Washington, DC.
NASA released a 'first light' 3D movie on, naturally, Super Bowl Sunday:
"This is a big moment in solar physics," says Vourlidas. "STEREO has
revealed the sun as it really is--a sphere of hot plasma and
intricately woven magnetic fields."
Each STEREO probe photographs half of the star and beams the images to
Earth. Researchers combine the two views to create a sphere. These
aren't just regular pictures, however. STEREO's telescopes are tuned to
four wavelengths of extreme ultraviolet radiation selected to trace key
aspects of solar activity such as flares, tsunamis and magnetic
filaments. Nothing escapes their attention.
"With data like these, we can fly around the sun to see what's
happening over the horizon—without ever leaving our desks," says
STEREO program scientist Lika Guhathakurta at NASA headquarters. "I
expect great advances in theoretical solar physics and space weather
forecasting."
Consider the following: In the past, an active sunspot could emerge on
the far side of the sun completely hidden from Earth. Then, the sun's
rotation could turn that region toward our planet, spitting flares and
clouds of plasma, with little warning.
"Not anymore," says Bill Murtagh, a senior forecaster at NOAA's Space
Weather Prediction Center in Boulder, Colorado. "Farside active regions
can no longer take us by surprise. Thanks to STEREO, we know they're
coming."
NOAA is already using 3D STEREO models of CMEs (billion-ton clouds of
plasma ejected by the sun) to improve space weather forecasts for
airlines, power companies, satellite operators, and other customers.
The full sun view should improve those forecasts even more.
The forecasting benefits aren't limited to Earth.
"With this nice global model, we can now track solar storms heading
toward other planets, too," points out Guhathakurta. "This is important
for NASA missions to Mercury, Mars, asteroids … you name it."
NASA has been building toward this moment since Oct. 2006 when the
STEREO probes left Earth, split up, and headed for positions on
opposite sides of the sun (movie). Feb. 6, 2011, was the date of
"opposition"—i.e., when STEREO-A and -B were 180 degrees apart,
each looking down on a different hemisphere. NASA's Earth-orbiting
Solar Dynamics Observatory is also monitoring the sun 24/7. Working
together, the STEREO-SDO fleet should be able to image the entire globe
for the next 8 years.
The new view could reveal connections previously overlooked. For
instance, researchers have long suspected that solar activity can "go
global," with eruptions on opposite sides of the sun triggering and
feeding off of one another. Now they can actually study the phenomenon.
The Great Eruption of August 2010 engulfed about 2/3rd of the stellar
surface with dozens of mutually interacting flares, shock waves, and
reverberating filaments. Much of the action was hidden from Earth, but
plainly visible to the STEREO-SDO fleet.
"There are many fundamental puzzles underlying solar activity," says
Vourlidas. "By monitoring the whole sun, we can find missing pieces."
Researchers say these first-look whole sun images are just a hint of
what's to come. Movies with even higher resolution and more action will
be released in the days and weeks ahead as more data are processed.
Stay tuned!
Related Links:
For more information about STEREO, please visit › www.nasa.gov/stereo.
› Download a self-guided Science Briefing explaining this historic "First".
