NASA has finally released a series of images showing, for the first time, the formation of coronal mass ejections (CME)
The U.S. space agency, working in collaboration with a team of international astronomers, announced the release of the images Friday, saying they had received extreme ultraviolet images from the Atmospheric Imaging Assembly (AIA) instrument on board NASA’s Solar Dynamics Observatory (SDO).
Angelos Vourlidas, a solar scientist at the Naval Research Laboratory in Washington, D.C., led the study, which was presented and published by the Astrophysical Journal on January 31 of this year. According to NASA, the images were captured during a July 18, 2012, mission and the images are are being described as the first ever captured sighting of how CMEs form and erupt from the surface of the sun. The images, described as gorgeous could provide astronomers with an unprecedented amount of data on how these strange sun formations occur and the driving force behind them.
Describing the images, NASA noted that they are extremely important to the astronomical community for one reason in particular: flux ropes. Astronomers spotted enormous magnetic entities – called flux ropes – stretching for hundreds of kilometres in the Sun’s upper atmosphere. Studying the images, NASA scientists now say they are confident flux ropes precede CMEs, which until now was largely an unconfirmed theory. According to NASA, such flux ropes have been seen in images of CMEs as they fly away from the sun, but it’s never been known – indeed, has been strongly debated – whether the flux ropes formed before or in conjunction with a CME’s launch.
In one of the captured images, the magnetic structure of the flux rope exists before the CME, and it continues over time to twist until ti become unstable, eventually erupting from the sun and releasing enormous amounts of energy and solar plasma. In the second image, the CME erupts when looping magnetic field lines are severed from the sun’s surface before the solar material streams off the sun and the fields reconnect with each other to form a classic flux rope shape.
“Seeing the structure was amazing,” says Vourlidas. “It looks exactly like the cartoon sketches theorists have been drawing of flux ropes since the 1970s. It was a series of figure eights lined up to look like a giant slinky on the Sun.”
While astronomers have long theorized that flux ropes formed before CMEs, until a few years ago NASA did not have the necessary instruments to capture various images of CMEs, allowing astronomers to confirm the hypothesis. Plasma physicists have long suggested that such coils of magnetic field lines were at the heart of flares in the 1970s and spacecraft near Earth provided in-situ measurements that occasionally traced out helical structures inside CMEs.
At one point, flux ropes were spotted in images of CMEs captured by the joint ESA/NASA Solar Heliospheric Observatory (SOHO) – which launched in 1995 – using the mission’s Large Angle and Spectrometric Coronagraph (LASCO), but astronomers were unable to use the images as firm confirmation of the theory.
Adding to the challenge is the fact CMEs form quite quickly and without warning. Since CMEs can form quite suddenly – known as impulsive CMEs – the associated flux ropes are smaller and closer to the surface, making it difficult to spot them amongst the many structures in the corona, according to NASA.
The finding is significant, says NASA. Spotting such a foreshadowing of a CME could help scientists develop ways to predict them, says Dean Pesnell, the project scientist for SDO at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Better projections could provide Earth with critical time to prepare ahead of CMEs. CMEs can cause a space weather phenomenon known as geomagnetic storms. These storms occur when charged particles (ejected in the form of a CME) slam into the Earth’s magnetic shield — known as the magnetosphere — for an extended period.
The image comes as NASA has spent the past several months preparing for the sun’s peak solar cycle. Astronomer say this year is will represent the peak of the sun’s thirteen-year cycle, resulting in a number of massive solar flares, sun spots, and CMEs. A number of studies have warned of possible solar superstorms CMEs, which could lead to widespread blackouts and disruptions to key technologies, such as GPS and weather satellites. One survey, released in mid-2012, estimated that a massive solar superstorm could cost the world economy upwards of $1 trillion.
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