The Sun has been imaged in unprecedented detail by a sophisticated solar laboratory in space, revealing new insights about the mysterious processes occurring in and around our star.
The new pictures were captured on March 7 by the European Space Agency’s Solar Orbiter as it crossed directly between Earth and the Sun, at a distance of about halfway between the two bodies. From this special orbital vantagepoint, the orbiter was able to capture the highest-resolution image of the Sun and its surrounding atmosphere, known as the corona, ever taken (there’s an interactive zoom feature for the image at this link).
The final composite shot was stitched together from 25 images, totalling 83 million pixels, snapped by the spacecraft’s Extreme Ultraviolet Imager (EUI).
The amazing mosaic, which has ten times the resolution of a 4K television screen, reveals tempestuous structures on the Sun’s surface that often erupt into flares and coronal mass ejections. These eruptions shoot wind and plasma out into the solar system, producing space weather that can fuel shimmering auroras in the night sky—or threaten electronics on satellites and Earth.
The Solar Orbiter also captured a dramatic image of the Sun, taken at the same wavelength of ultraviolet light emitted by hydrogen gas, with its Spectral Imaging of the Coronal Environment (SPICE) instrument. As with the EUI instrument, these were also compiled from multiple shots that show hydrogen color-coded at different temperatures around the Sun, from purple at 10,000°C to neon at 630,000°C.
First and foremost, these pictures offer never-before-seen views of our star that are stunning to behold. But the Solar Orbiter team also hopes to use them, and future images taken by the mission, to solve persistent riddles about the Sun.
For instance, the spacecraft could help scientists understand why the surface of the Sun is about 5,000°C, whereas the corona can reach an astonishing 1,000,000°C. Nobody knows exactly why the corona can be so much hotter than the solar surface, but the answer will have implications for a host of other important processes, such as the creation of the solar wind.
The Solar Orbiter has now passed inside of the orbit of Mercury, and will settle into its permanent path around the Sun in the coming years. In addition to these detailed pictures, the mission is designed to capture rare glimpses of the Sun’s poles. Solar Orbiter is one of many next-generation missions that are peeling back the Sun’s layers, including NASA's Parker Solar Probe and the Inouye Solar Telescope. Together, these observatories stand to revolutionize our understanding of our star, and by extensions, star systems across the universe.