Monday’s total solar eclipse lent unearthly vibes all round in North America. Across North America where the solar eclipse’s shadow streaked past for nearly two hours, all chatter subsided. Even radio signals would’ve gone awry in places, as people across the US, Canada and Mexico America peered at the sky as the color slowly drained from the sky when the moon eclipsed the sun.
If it hadn’t been for the red tendril-like features extending out from the sun in several captures of the eclipse event, one would’ve thought that our sun collapsed into a black hole – in fact, reminiscent of Gargantua from Christopher Nolan’s Interstellar (2014).
Chatter soon broke out on the internet following the first sighting. Pictures of the solar eclipse was shared across social media platforms, taken from places and vantage points within and outside of the shadow’s trajectory across North America.
The red-tendril-like features, or the solar prominence as it’s described by astronomers, is a plume of plasma that outlines the sun’s extensive but otherwise invisible magnetic field. The plasma trails the shape of the field lines there, giving it the appearance of that filament. Moreover, the white hot corona in the image is remarkably over millions of degrees hotter than the sun’s outer layer. The invisible beauty of our sun now is unraveled as we see the naked truth, with the surrounding sky turning pitch black of empty space in the meantime.
A solar prominence event where loops of hot plasma is wound in a loop by the sun’s magnetic field. Credit: NASA
Features like the prominence have long been known to astronomers for centuries. Solar eclipses are perhaps amongst the only times when day-light astronomy could be done.
History is replete with records of scientists making important discoveries during solar eclipses. For example, in 1868, the French astronomer Pierre Janssen detected a signature of a then unknown element inadvertently as he observed a solar eclipse from Madras State in colonial India. Further detections by the English astronomer Norman Lockyer later in the same year conclusively established the new element – named helium ( after the Greek ἥλιος or helios meaning the sun).
Not just that, the English astrophysicist Arthur Eddington carried out experiments involving sunlight amidst the solar eclipse in 1919, whose results had Albert Einstein’s theory of general relativity prevail over Isaac Newton’s gravitational theory. Eddington and other researchers had captured the precise deflection angle by which the sun’s gravitational field bent light from background stars.
Fast forward to today, Monday’s solar eclipse left an open window to do some important science. Not of the sun, but investigating the interactions between the sun and earth’s upper atmosphere – particularly the ionosphere, which lies above the stratosphere, at over 60 to 300 km. Everyday long distance radio communication is possible because the radio transmissions get deflected by this layer, which is ionized (presence of charged atoms and negatively charged electrons), in part due to solar radiation from the sun.
But during solar eclipses, the ionosphere is suddenly caught in disarray, even hampering radio communications. However, Monday’s solar eclipse found ways to turn even ordinary citizens into scientists, beaming radio signals at the ionosphere in an effort at scientific experimentation and establishing alternate forms of communication.
The Ham Radio Science Citizen Investigation (HamSCI) is one effort in the US during Monday’s eclipse that linked up amateur radio ham operators across North America, for data gathering.
As much as there is genuine scientific curiosity motivating the experiments, there are clear societal reasons why these efforts are more important than ever. Understanding how reflective the ionosphere can be, should help better inform emergency response teams to use forms of radio signaling that may work effectively amidst hostile space weather – as it did during Hurricane Irma in 2017.
A radio ham set. Credit: Wikimedia
With citizens as both participants and organizers, they can help scientific estimates of the electron density in the ionosphere and how much it attenuates there.
The more modern rendition of participatory science, or ‘citizen science’, makes its presence felt during these times, as they keep the culture and ancient tradition that is astronomy alive in new ways. And in doing so, their efforts stand testimony to how ordinary people can take up the lead in place of scientists, to act in service of both science and society.