Scientists have successfully modified the Solar Orbiter’s Extreme Ultraviolet Imager (EUI) to capture images of the Sun’s corona in a new mode of operation termed “occulter mode”.
The modification, which was described as a “hack” by researchers on the EUI team, involves placing a “thumb” in front of the sun to be able to see its atmosphere – otherwise known as the corona.
Rule of Thumb: Unveiling a Solar Occulter Mode
The principle is shockingly simple and allows scientists to see the sun’s corona in ways not previously possible. But it’s something that almost all of us have done at some point on a bright and sunny day.
Imagine, if you will, you’re standing on the beach and the sun’s in front of you. Looking in its direction can be quite blinding, making it difficult to make out a lot of the details, especially in the sky around the sun itself.
It was really a hack. I had the idea to just do it and see if it would work. It is actually a very simple modification to the instrument.Frédéric Auchère, Institut d’Astrophysique Spatiale, Université Paris-Sud, and EUI team member
You hold up your hand to shade your eyes from the sun, allowing you to see what’s going on around you. You can even see details in the clouds surrounding the sun, now that your eyes have been able to adjust.
The same basic logic is applied here. A protruding “thumb” was placed in front of the camera, blocking the light coming directly from the sun. This allows them to see the relatively low-contrast corona against the rest of space’s nothingness without it being blown out by the sun’s light.
A Glimmer in the Darkness: Why Occulter Mode Matters
The occulter mode thumb hack is a game-changer for solar physics. It allows scientists to see things that have previously been impossible to see. At least, they are impossible to see except under rare and very short-lived conditions.
During a total eclipse, where the moon blocks the path between Earth and the sun, we can see its corona relatively easily. But such events don’t happen every day. And when they do happen, they last for minutes at most.
Scientists plan experiments years in advance, waiting for the time when a solar eclipse allows them to perform them. It’s why there are so many experiments going on and being talked about on the news and online whenever a total eclipse happens.
Occulter mode essentially mimics the same sort of effect as an eclipse, allowing us to see the corona more clearly.
Burning Questions: The Mysteries the New Mode Could Solve
The sun’s corona has confused and confounded scientists for years, as its temperature is higher than that of the sun itself. This paradox has been one of the greatest mysteries of the body at the centre of our solar system.
It also allows us to learn more about solar winds. Solar winds are streams of charged particles released from the sun which interact with Earth’s magnetic fields. The mechanisms behind the origin and acceleration of these winds are still largely a mystery.
The sun’s magnetic field also plays a critical role in various solar weather phenomena, such as solar flares and sunspots. Occulter mode may allow us to observe these events to better understand what causes them and how we might be able to predict them in the future.
Like Earth, the sun has multiple layers, each with its own unique properties. We pretty much understand how things work here on Earth, but the sun’s layers and the interactions between them are also still a mystery.
Not just a fancy camera trick
So, as you can see, while the principle is quite simple, it has far-reaching and complex implications. The innovative concept allows scientists to essentially simulate an eclipse any time they like and uncover the mysteries of the big fiery ball in the centre of our solar system.
It will be interesting to see which of those mysteries is not only tackled first, but which are figured out first, and what may come as a result of those discoveries.
Sometimes, the simple hunch or idea pays off. I think that deserves a big thumbs up for Frédéric Auchère!
The researchers have written a paper on the technique which you can read on the Astronomy & Astrophysics website.