Revealing a wealth of information and incredible photography, NASA has taken images of the edge of the sun for the first time, detailing where its powerful solar winds start.
In the field of astronomy, solar winds are a relatively new discovery, first discovered only in the 1950s. Until now, their origins had remained something of a mystery.
Now, using NASA’s Solar Terrestrial Relations Observatory (STEREO), scientists in the US space agency have, for the first time, taken images of the edge of the sun, revealing exactly where solar winds start.
Key to the insight was analysing the sun’s plasma. This mix of positively- and negatively-charged particles travels around the star’s magnetic lines. Upon reaching the edge of the sun’s coronal area, or atmosphere, the plasma is emitted into space as solar wind.
The scientists behind the discovery noticed that the further out from the sun the plasma traveled, the less magnetic control the sun had over it. This loss of control forms the boundary of the outer corona.
“As you go farther from the sun, the magnetic field strength drops faster than the pressure of the material does,” said Craig DeForest, who led the study.
“Eventually, the material starts to act more like a gas, and less like a magnetically-structured plasma.”
The newly-released images of the sun’s edge capture the moment the corona becomes solar winds.
Before this study, scientists had hypothesised that the sun’s magnetic forces were key to shaping the edge of its corona, but the sheer challenge of processing these images meant it had never before been observed.
The NASA researchers analysed the point just over 30 million km from the sun where solar winds begin, a task requiring careful image processing.
Computer-processed data of the solar wind. Image via data from Craig DeForest, SwRI
These images of the corona fading into the solar wind were key to solving the solar wind origin story.
Efforts to capture images of the edge of our sun have increased in recent years, with the European Space Agency (ESA) announcing last month that it plans to send a solar eclipse-creating satellite to monitor the sun’s corona in 2019.
Coronal ejection image via Shutterstock
