Thanks to the hard work of two vigilant astronomers, one of the great mysteries surrounding solar magnetic fields is a mystery no longer.

The two scientists, David McKenzie of Montana State University at Bozeman and Hugh Hudson of the Institute of Space and Astronautical Science in Japan, have witnessed for the first time evidence of a mysterious solar phenomenon long thought to exist, but never before seen. Known to experts as "magnetic-field line shrinkage" or "reconnection outflow," the behavior involves magnetic fields snapping back to the sun as if being pulled and then released like a rubber band.

"This is the motion weve been looking for, and now weve been able to spot it," said McKenzie.

These images show the "snapping" effect of the suns magnetic field. The white arrow represents where one magnetic-field line begins as it is being pulled from the suns surface. The black arrows show where the lines edge moves, as it is pulled back toward the solar surface.

Then starting in the mid 1970s, astronomers attempted to come up with a theory behind the X-ray arcades. One hypothesis assumed that they are emissions from magnetic-field lines associated with the sun. The theory further suggested that when the sun releases massive amounts of energy during coronal mass ejections, outward-flowing magnetic-field lines would be visible by their emissions of X-ray material (the arcades) flowing outward from the sun.

But some experts also thought that during solar flares and coronal mass ejections, some portions of the suns magnetic field lines would remain "grounded" on the solar surface. And as solar flares and coronal mass ejections take place, magnetic fields that arent completely spewed out to space would spring back to the sun.

As it turns out, these experts were right.

"Magnetic fields support tension that is, if you stretch out a magnetic-field line, it will snap back into place just like a rubber band will," McKenzie told SPACE.com. "The ejection of material from the sun can stretch out the embedded magnetic field, and when its connections get rearranged, portions of the field that are connected to the sun but no longer connected to the ejected material willretract back towards the suns surface."

McKenzie and Hudson confirmed the magnetic-field snapping hypothesis after they, by chance, found the evidence they were looking for while working with the soft X-ray telescope on the Yohkoh solar observatory satellite.

"The observations were made possible by a serendipity," said McKenzie. Although he and Hudson had known that their instruments could allow for observation of material flowing away from the sun, it turned out that "the set-up also proved quite useful for watching flows into" the sun, he said.