A Massive Explosion on the Sun

April 25, 2007
A Massive Explosion on the Sun

Astronomers are calling the Japanese Hinode spacecraft a "Hubble for the sun." Watch this movie and you'll see why.

The footage, gathered by Hinode's Solar Optical Telescope (SOT) on Dec. 13, 2006, shows sunspot 930 unleashing a powerful X-class solar flare. It's one of the most detailed movies of a flare solar physicists have ever seen. The SOT has a resolution of 0.2 arcseconds or 0.00006 degrees. Putting those numbers into perspective, the telescope can see features on the sun as small as 90 miles wide from its orbit 93 million miles away.

But resolution is only part of the story. What makes Hinode truly special as a solar telescope "is its unique ability to see the sun's magnetic field," says John Davis, NASA's project scientist for Hinode at the Marshall Space Flight Center. It's an ability Hinode used to reveal the magnetic underpinnings of the Dec. 13th flare.

"Solar flares are essentially magnetic," Davis explains. In the maelstrom above a sunspot, lines of magnetic force are twisted and stretched until the tension reaches a certain point—and then the whole thing explodes.

A rubber band provides a good analogy. Take one from your desk, hold one end in each hand: stretch and twist. If you twist, twist and twist to extremes, the tormented band will eventually snap, painfully releasing all the energy you just put into it.

Magnetic fields behave a lot like rubber bands, and "Hinode was able to see the twisting and stretching that preceded the Dec. 13th solar flare," he says.

Regard the animation at right. It looks like a rampaging hurricane--about twice as wide as Earth! In fact, it is a magnetic map of the flare zone on the southern flanks of sunspot 930. Red arrows indicate the direction of the sunspot's magnetic field. White areas have positive polarity (N); black areas are negative (S). The movie begins on Dec. 10th, three days before the flare, and ends on Dec. 14th, one day after the flare.

"These data were recorded by Hinode's spectro-polarimeter, a device which can sense magnetic fields by analyzing the polarization of light coming from iron ions in the sun's atmosphere," explains Davis.

The hurricane, he says, is actually a giant tube of magnetic flux emerging from beneath the sun's surface. As it spins, lines of magnetic force become twisted and stretched, while N and S polarities are shoved together in close proximity. "This causes a build-up of tension and energy in the magnetic field."

On Dec. 13, 2006, at precisely 0234 UT, the energy was released in the form of an X3-category solar flare. The explosion hurled a coronal mass ejection (CME: a billion-ton cloud of gas) into space, which sparked Northern Lights as far south as Arizona when it hit Earth a day later. Shock waves in the CME accelerated heavy ions to near-light speed, and these ions coursed around the Earth and Moon for more than a day. This is called a "radiation storm." If astronauts had been on the Moon at the time, they may have been forced to stay indoors—inside their spaceships or habitats—to avoid exposure.

Astronomers have been struggling to predict solar flares since flares were discovered in 1859 by Lord R.C. Carrington and R. Hodgson. But they have been stymied, in part, by the difficulties of mapping the sun's magnetic field. Magnetograms on Earth must look through our planet's turbulent atmosphere, which blurs the little red arrows we see so clearly in the Hinode movie. Hinode's ability to examine magnetic fields from Earth orbit is a new and crucial development.

"The kind of data we're getting from Hinode is just what we need to sort out how flares work," says Davis. "All we need now is some more explosions."

Hinode is a joint mission of the Japan Aerospace Exploration Agency (JAXA), the National Astronomical Observatory of Japan (NAOJ), the National Aeronautics and Space Administration (NASA) and the Particle Physics and Astronomy Research Council (PPARC). The Marshall Space Flight Center managed the NASA instrument component integration for NASA Headquarters, is managing the science operations for NASA and is also supporting science operations in Japan.

Source: by Dr. Tony Phillips, Science@NASA

Explore further: IRIS and Hinode: A Stellar research team

Related Stories

IRIS and Hinode: A Stellar research team

August 25, 2015

Modern telescopes and satellites have helped us measure the blazing hot temperatures of the sun from afar. Mostly the temperatures follow a clear pattern: The sun produces energy by fusing hydrogen in its core, so the layers ...

Searing sun seen in X-rays

July 8, 2015

X-rays light up the surface of our sun in a bouquet of colours in this new image containing data from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR. The high-energy X-rays seen by NuSTAR are shown in blue, while ...

Solar tsunami used to measure Sun's magnetic field

July 11, 2013

(Phys.org) —A solar tsunami observed by NASA's Solar Dynamics Observatory (SDO) and the Japanese Hinode spacecraft has been used to provide the first accurate estimates of the Sun's magnetic field.

Hinode to support ground-based eclipse observations

November 13, 2012

(Phys.org)—On Nov. 13, 2012, certain parts of Earth will experience a total solar eclipse, which, like all eclipses, will only be visible when you are aligned in a straight line with the moon and the sun. In this case the ...

Recommended for you

New Horizons team selects potential Kuiper Belt flyby target

August 29, 2015

NASA has selected the potential next destination for the New Horizons mission to visit after its historic July 14 flyby of the Pluto system. The destination is a small Kuiper Belt object (KBO) known as 2014 MU69 that orbits ...

Dawn spacecraft sends sharper scenes from Ceres

August 25, 2015

The closest-yet views of Ceres, delivered by NASA's Dawn spacecraft, show the small world's features in unprecedented detail, including Ceres' tall, conical mountain; crater formation features and narrow, braided fractures.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.