INTERVIEW | NASA heliophysicist Craig Edward DeForest says this

Flares from the sun’s surface and the powerful pulse of charged particles that shoot through space carry both delight and danger. They bring along the treat of effulgent lights, those surreal auroras across polar skies, and the threat of disruption.

Coronal mass ejections (CMEs) from the sun can affect the solar system. Recent Chandrayaan-2 observations, for instance, showed how a CME altered the moon’s thin exosphere.

Similarly, on 24 April 2023, the Earth’s magnetic field was exposed to one such ejection. What followed were breathtaking, yet potentially hazardous, auroras across higher latitudes.

It was yet another reminder that the star that sustains life on Earth can also turn volatile. The same energy that nurtures us can, at times, imperil what our civilisation now depends on most — technology.

With nations competing in the new space race, the stakes are high. A single geomagnetic storm can damage satellites and communication networks. The risk is even greater for astronauts aboard the International Space Station, who are exposed daily to 0.5 to 1 millisievert of cosmic radiation, including that from the sun.

During periods of heightened solar activity, that exposure can more than double — increasing the chances of DNA mutations and even cancer. For India, with its upcoming Gaganyaan mission and plans for the Bharat Antariksh Station, understanding solar behaviour is a matter of both curiosity and survival.

In fact, there has been a global surge in heliophysics research. India’s Aditya-L1 mission and NASA’s PUNCH (Polarimeter to Unify the Corona and Heliosphere) project are part of this collective effort to understand the sun’s temperament.

A significant part of PUNCH was, quite literally, in Kerala a couple of days ago when its principal investigator, Craig Edward DeForest, visited Thiruvananthapuram to take part in an IIST symposium and deliver an engaging lecture titled ‘Imaging Almost Nothing at All’.

The event, organised by the Breakthrough Science Society (BSS), Christ (Deemed to be University), and IIST, drew scientists and students alike. All eager to listen to the man whose work peers deep into the sun’s invisible storms.

Craig’s fascination with the Sun began nearly five decades ago. He recalls being transfixed by the crimson glow of the setting sun as an 11-year-old. The same light that made him squint and yet refuse to look away.

“Till then,” he says, “the sun was just there — a common, predictable presence.” But that moment sparked a curiosity that refused to fade.

He questioned his father, scoured books, and eventually pursued physics. That childhood wonder turned into a lifelong devotion, leading him to heliophysics.

Today, at 57, he heads NASA’s PUNCH mission, studying coronal mass ejections and solar storms. Excerpts from an interaction:

Of late, we have been coming across reports of increased solar activity. What’s happening out there?

Just as the earth reverses its cycle every 30,000 years, the more energetic sun flips its magnetic field every 11 years. When that happens, when north becomes south, solar activity surges. Sunspots, space weather, and flares are all linked to that magnetic reversal.

Moreover, we are able to measure it better. We have been tracking space weather for only about 40 years — four solar cycles. That period coincided with a quiet phase. Now, activity is returning to historical levels. We are seeing much more intense space weather.

How serious is the impact of this on earth?

Had we still been living in the Stone Age, not at all. But now, we live in a tech-driven world. We use technology in every aspect of our lives. So, we should care. People managing power grids, satellites, and aircraft should care. Even farmers, since modern agriculture relies on GPS.

What’s the impact of space weather on Earth’s system?

The sun, of course, influences climate change. Contrary to the popular notion, the star is actually cooling off at the moment. The average solar radiation is lower than it was in the 1990s. We are not entirely sure why.

As the sun ages, it should grow hotter and brighter. When its hydrogen runs out in, say, a few billion years from now, the core will contract and heat up before the star collapses. But the scientific feedback we are getting is opposite to what one might expect. We still don’t fully understand what’s happening.

What is NASA’s PUNCH aiming to do?

For the first time, we have the combination of optics, detectors, and ground-based analysis to create 3D images of solar activity. PUNCH focuses on solar winds, capturing extremely faint phenomena such as space-weather storms using wide-field cameras.

Your lecture was titled ‘Imaging Almost Nothing at All’. Sounded like a hint about the vastness…

Exactly. We are literally imaging almost nothing. On Earth, there are about a lakh crore molecules in every millilitre of air. In interplanetary space, there may be just one to ten. Yet, these sparse particles can manifest as gusts or storms and streams of wind. We are studying these for various reasons. A primary objective is to safeguard scientific activity going on around the earth in terms of space exploration and experiments.

India is planning a manned mission and a space station soon…

We should be able to forecast space weather for all such experiments. Any satellite operator should care. One effect of geomagnetic solar storms is the heating and expansion of the earth’s upper atmosphere. When that happens, satellites can experience drag and even fall. SpaceX once lost 80 satellites. They launched during a solar storm when the air was unusually expanded. If they had known, they could have postponed the launch.

Is there give-and-take between PUNCH and other solar missions?

Absolutely. India’s Aditya-L1 is a phenomenal mission. PUNCH creates 3D images of the solar environment using light from interplanetary space. We combine this with data from other missions such as NASA’s Parker Solar Probe, European Space Agency’s Solar Orbiter, and India’s Aditya. Together, they give a clearer picture of solar dynamics. Aditya certainly has a role to play.

What about the need for outreach?

It’s very important. One of the reasons why we do this is because these knowledge systems are fascinating. And this reason also draws people to science. We need to stimulate excitement, especially among the youth. Sharing that excitement serves the goal of nations and makes lives better.

Do these technologies have an effect in other fields of study?

Yes. The imaging processing we do, for example, has spill-overs in amateur astronomy, terrestrial imaging, and medical imaging. Collaboration is key, among disciplines and among people. The global solar-physics community is tightly knit. We share data and collaborate. Politicians may compete, but as scientists, we have devoted our lives to unravel the truths of the universe. It is a higher calling. I truly believe scientific communities can bring together nations through the simple act of collaborating.

[Written by Aparna Nair of The New Indian Express]