We are all pretty familiar with the host star that sustains life on Earth, but the Sun’s boiling hot atmosphere still contains many mysteries.
Now, the highest resolution images of the Sun ever taken reveal previously unknown details of the star's roiling outer layer. And they are truly incredible.
The images were captured by the space-based NASA High-Resolution Coronal Imager telescope (Hi-C), and then analyzed by a team of scientists from both NASA and the University of Central Lancashire in the United Kingdom.
The stunning images reveal the outermost layer of the Sun’s atmosphere, previously believed to be somewhat bare, is actually teeming with snake-like, thin, magnetic threads, filled with boiling hot plasma. The plasma, which is essentially hot, electrified gas, reaches millions of degrees Fahrenheit.
The images are detailed in research published this week in The Astrophysical Journal.
Aside the unprecedented view of our Sun, the study offers new insight into the star's massive solar storms.
Stormy weather — The new images show the plasma threads swirling around in a hypnotic dance across the Sun’s outer layer.
These strands look small to our view, but they are actually 500 kilometers wide. Each strand may be as hot as 1.8 million degrees Fahrenheit, according to the researchers.
Scientists are not sure what may have caused these threads to exist, but they believe that understanding how they formed can help provide a better understanding of the Sun’s unpredictable solar weather.
The Sun periodically ejects boiling-hot plasma, in the form of solar flares and solar wind, across the Solar System.
But until now, scientists didn't know what causes the Sun to erupt into violent storms, or where these solar flares originate from.
But as our ability to view the Sun improves with more advanced technology, we are able to glimpse the chaotic dynamics of our host star in greater detail.
“Until now solar astronomers have effectively been viewing our closest star in ‘standard definition’, whereas the exceptional quality of the data provided by the Hi-C telescope allows us to survey a patch of the Sun in ‘ultra-high definition’ for the first time," Robert Walsh, professor of Solar Physics at University of Central Lancashire and institutional lead for the Hi-C team, said in a statement.
The images follow on from similarly stunning observations made in January 2020, when the National Science Foundation's Daniel K. Inouye Solar Telescope released the highest-resolution images of the Sun's surface. These revealed honeycomb-like cells of hot gas that cover the entire star. These cell-like structures, each about the size of Texas, are also believed to contain clues to solar storms.
In addition to these groundbreaking telescopes, the world's space agencies recently launched missions to study our host star up-close. In February 2020, NASA and the European Space Agency launched the Solar Orbiter.
It joins another spacecraft currently orbiting the Sun, NASA's Solar Parker Probe. The probe launched in August, 2018, and is designed to dive into the Sun’s atmosphere and collect data on solar wind and the star’s magnetic field.
“These new Hi-C images give us a remarkable insight into the Sun’s atmosphere," Amy Winebarger, Hi-C principal investigator at NASA, said in a statement.
"Along with ongoing missions such as Probe and SolO, this fleet of space-based instruments in the near future will reveal the Sun’s dynamic outer layer in a completely new light.”
We can't wait to see it.
Abstract: Following the success of the first mission, the High-Resolution Coronal Imager (Hi-C) was launched for a third time (Hi-C 2.1) on 2018 May 29 from the White Sands Missile Range, NM, USA. On this occasion, 329 s of 17.2 nm data of target active region AR 12712 were captured with a cadence of ≈4 s, and a plate scale of 0129 pixel−1. Using data captured by Hi-C 2.1 and co-aligned observations from SDO/AIA 17.1 nm, we investigate the widths of 49 coronal strands. We search for evidence of substructure within the strands that is not detected by AIA, and further consider whether these strands are fully resolved by Hi-C 2.1. With the aid of multi-scale Gaussian normalization, strands from a region of low emission that can only be visualized against the contrast of the darker, underlying moss are studied. A comparison is made between these low-emission strands and those from regions of higher emission within the target active region. It is found that Hi-C 2.1 can resolve individual strands as small as ≈202 km, though the more typical strand widths seen are ≈513 km. For coronal strands within the region of low emission, the most likely width is significantly narrower than the high-emission strands at ≈388 km. This places the low-emission coronal strands beneath the resolving capabilities of SDO/AIA, highlighting the need for a permanent solar observatory with the resolving power of Hi-C.