A spectacular solar show
NASA-GSFC NEWS RELEASE
Posted: November 3, 2002

Sun
Image courtesy of SOHO/NASA/ESA
 
Not to be outdone by fall's explosion of color, the Sun issued a series of spectacular solar eruptions, which were photographed by the Solar and Heliospheric Observatory (SOHO) spacecraft.

These beautiful but violent solar events are important to solar science and can affect high-technology systems. "Understanding the processes beneath the Sun's surface that drive these eruptions is critical to understanding the Sun's behavior and its influence on our planet," said Dr. Gareth Lawrence of the Catholic University of America, who is stationed at NASA's Goddard Space Flight Center, Greenbelt, Md., as the Operations Scientist for the Large Angle and Spectrometric Coronagraph (LASCO) instrument on SOHO.

Sun
The first CME, perplexed even seasoned solar physicists with its unique appearance. Coronal mass ejections tend to take on a shape that resembles a "lightbulb". This one, however, had more the shape of a dark keyhole, or a bulb on top of a column. The most likely explanation appears to be a combination of several coincidences - the chance juxtaposition of unrelated solar structures, enhanced by the image processing that removes the "background image", and a visual illusion that enhances the apparent contrast of the column. Image courtesy of SOHO/NASA/ESA
 
The solar fireworks began October 24 with an immense eruption of electrically charged gas (plasma) called a coronal mass ejection (CME). It was observed with the LASCO instrument, which has a disk that blocks direct light from the Sun so the much dimmer solar atmosphere can be seen. The CME had a unique appearance and has been named the ³Keyhole CME².

"We've observed thousands of CMEs, but none ever looked like this one," said Dr. Stein Vidar Hagfors Haugan of the European Space Agency, a solar scientist with the SOHO program, also stationed at NASA Goddard. SOHO scientists believe a combination of effects from nearby solar structures, SOHO's viewing position, and an enhancement from image-processing techniques produced the dark area resembling a keyhole in the image.

A second CME, also seen with LASCO, erupted October 25 and vaguely resembles a corkscrew, with twisted lines bursting from the Sun. According to SOHO scientists, its unusual appearance is due to twisted solar magnetic fields, which steer the flow of the CME plasma. Part of the Sun's interior magnetic field becomes twisted from activity deep inside the Sun. It is eventually ejected from the Sun following an explosive energy release process. Details regarding how the fields become twisted and the exact mechanisms that propel CMEs into space are the focus of intense research activity.

Sun
The second CME (above, left) showed an unusually high level of structure, with a definite "twist" to the material being ejected. Image courtesy of SOHO/NASA/ESA
 
CMEs are billion-ton eruptions of plasma from the Sun. CMEs are blasted from the Sun at high speeds, ranging from 125 to 1,550 miles per second (about 200 to 2,500 kilometers per second). Normally the ones directed at Earth are potentially harmful, depending on the orientation of the magnetic field in the CME plasma cloud, the CME's speed, and the plasma density.

If directed at Earth, the CME plasma is harmless to people but slams into the Earth's magnetic field, distorting it like a jellyfish buffeted by a strong current. The alteration in the shape of the Earth's magnetic field accelerates electrically charged particles (electrons and atomic nuclei) trapped within. The rapidly-moving particles sometimes generate beautiful auroral displays (northern and southern lights) when they collide with the upper atmosphere around the polar regions. The most severe CME impacts cause geomagnetic storms capable of disrupting satellites, radio communications, and power systems. Neither the keyhole nor the corkscrew CME were heading toward Earth, so they aren't expected to produce strong geomagnetic storm effects.

Sun
Three images from CME. Image courtesy of SOHO/NASA/ESA
 
The Sun punctuated its performance with an eruptive prominence on October 25. It was seen with the Extreme ultraviolet Imaging Telescope (EIT) instrument on SOHO, which looks directly at the solar disk and can observe cooler gas near the surface. Prominences are huge clouds of relatively cool, dense plasma suspended by magnetic fields in the Sun's hot, thin, outer atmosphere (corona). They occur when dense plasma at the solar surface becomes trapped in magnetic fields that are propelled high into the corona.

They frequently linger for a week or two and sometimes suddenly erupt, escaping into space. Other times, the plasma slowly drains back to the solar surface under the influence of the Sun's powerful gravity, 28 times stronger than Earth's. More research is needed before solar scientists can agree on what pushes prominences into the corona and why they sometimes fly off into space. Part of the eruptive prominence was Earth-directed, although it did not generate significant storm activity.

Sun
Illustration with size comparison to Earth. Image courtesy of SOHO/NASA/ESA
 

The ultimate Apollo 11 DVD
NEW 3-DISC EDITION This exceptional chronicle of the historic Apollo 11 lunar landing mission features new digital transfers of film and television coverage unmatched by any other.
 U.S. STORE
 U.K. & WORLDWIDE STORE

Hubble Calendar
NEW! This remarkable calendar features stunning images of planets, stars, gaseous nebulae, and galaxies captured by NASA's orbiting Hubble Space Telescope.
 U.S. STORE
 U.K. & WORLDWIDE STORE

Apollo 11 special patch
Special collectors' patch marking the 35th anniversary of the historic Apollo 11 moon landing is now available.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Inside Apollo mission control
An insider's view of how Apollo flight controllers operated and just what they faced when events were crucial.
 Choose your store:
U.S.

The ultimate Apollo 11 DVD
This exceptional chronicle of the historic Apollo 11 lunar landing mission features new digital transfers of film and television coverage unmatched by any other.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Next ISS crew
Own a little piece of history with this official patch for the International Space Station's Expedition 11 crew. We'll ship yours today!
 Choose your store:
U.S.

Apollo 15 DVDs
Bring a unique piece of space history to your living room. Two- and six-disc Apollo 15 DVDs will be shipping soon.
 U.S. STORE
 U.K. & WORLDWIDE STORE

Hubble
Astronomy Now presents Hubble: the space telescope's view of the cosmos. A collection of the best images from the world’s premier space observatory.
 U.S. STORE
 U.K. & WORLDWIDE STORE
An insider's view of how Apollo flight controllers operated and just what they faced when events were crucial.
 Choose your store:
U.S.

Mars rover collectible patch

Free shipping to U.S. addresses!

This commemorative patch celebrates NASA's Curiosity rover mission of the Mars Science Laboratory in search of clues whether the Red Planet was once hospitable to life.
 U.S. STORE
 WORLDWIDE STORE


Get e-mail updates
Sign up for our NewsAlert service and have the latest news in astronomy and space e-mailed direct to your desktop (privacy note: your e-mail address will not be used for any other purpose).
Enter your e-mail address:

STS-134 Patch

Free shipping to U.S. addresses!

The final planned flight of space shuttle Endeavour is symbolized in the official embroidered crew patch for STS-134. Available in our store!
 U.S. STORE
 WORLDWIDE STORE

Final Shuttle Mission Patch

Free shipping to U.S. addresses!

The crew emblem for the final space shuttle mission is now available in our store. Get this piece of history!
 U.S. STORE
 WORLDWIDE STORE

Apollo Collage
This beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.
 U.S. STORE

STS-133 Patch

Free shipping to U.S. addresses!

The final planned flight of space shuttle Discovery is symbolized in the official embroidered crew patch for STS-133. Available in our store!
 U.S. STORE
 WORLDWIDE STORE

Anniversary Shuttle Patch

Free shipping to U.S. addresses!

This embroidered patch commemorates the 30th anniversary of the Space Shuttle Program. The design features the space shuttle Columbia's historic maiden flight of April 12, 1981.
 U.S. STORE
 WORLDWIDE STORE

Mercury anniversary

Free shipping to U.S. addresses!


Celebrate the 50th anniversary of Alan Shephard's historic Mercury mission with this collectors' item, the official commemorative embroidered patch.
 U.S. STORE
 WORLDWIDE STORE

INDEX | PLUS | NEWS ARCHIVE | LAUNCH SCHEDULE
ASTRONOMY NOW | STORE

ADVERTISE

© 2014 Spaceflight Now Inc.