Why this years solar eclipse is great for scientists and the start of something even greater

Studying by sunlight

On June 8, 1918, the Cleveland Indians bested Babe Ruth and his Boston Red Sox 3-1. The New York Times reported that Germany was taking steps for the next war. And yet the big news of that day was about the total solar eclipse that crossed the United States from Oregon to Florida.

That was almost 100 years ago and the last time the U.S. experienced such a spectacular event over a wide swath of the nation. While not everyone will get the opportunity to see the #GreatAmericanEclipse in totality this August 21 (only those in the direct path of the eclipse ever do), the entire country will be treated to some portion of that eclipse, which is also mesmerizing.

Its rare when an eclipses path crosses so much land, offering more people a chance to experience the rarity. While this is obviously a fascinating experience in its own right, for scientists like myself this occasion represents so much more. As the director of the National Science Foundation (NSF) and as an astrophysicist, I see it not just as a moment to marvel at one of natures most impressive spectacles, but as an opportunity to learn and gain important even rare new information about our life-sustaining sun.

Its all about the corona

The scientific beauty of a total solar eclipse is that it gives us an amazing view of the suns corona, the suns upper atmosphere. The corona looks almost like a gossamer halo of light, appearing to surround the moon as it completely blocks the sun. At this point of totality which only lasts about 2 minutes scientists make observations and collect important data about the corona because thats where the suns most violent and curious activity occurs. Flares, plumes, coronal mass ejections are all impressively explosive events emitting electromagnetic activity so powerful it can impact communications systems and power grids here on Earth. Its what weve come to call space weather.

A total solar eclipse uniquely provides this clear view of the corona -- when we have the best chance to capture data to understand what precipitates the suns most explosive activity, ultimately improving space weather prediction and minimizing impacts to technology infrastructure on our own planet. Its why NSFs National Center for Atmospheric Research will fly a Gulfstream V plane armed with a spectrometer to capture infrared data from a higher vantage over a greater area of the eclipses path than standing in one place, and its why NSFs National Solar Observatory has orchestrated an impressive citizen science project to collect data from 68 sites spread across the path of totality.

Solving the coronal heating problem

The corona provides an age-old puzzle in its own right. And with each total solar eclipse, we get closer to solving that puzzle: Why is the sun's corona so hot?

Usually, the further you get from something hot, the cooler it gets. Not so with the sun. The sun's core is a searing 15 million degrees Kelvin, but by the time that heat reaches the sun's surface, it cools off to just 6,000 degrees, only to again heat up to more than a million degrees in the corona. Solar physicists, beginning astronomy students and many others have debated the reason for this seemingly odd phenomenon that we now know happens not just with the sun, but with other stars. NSF-funded researchers have been using tools like spectrometers or coronagraphs that help artificially block the sun in a way similar to a total eclipse to gather more data about the corona and try to find an answer. However, a total solar eclipse remains the best opportunity to capture the most accurate data.

Piquing the interest of future solar physicists

Additionally, with this total solar eclipse, NSFs National Solar Observatory has prepared a precedent-setting project -- The Citizen CATE Experiment that will involve scientists, students and volunteers who will track the sun using 68 identical telescopes, software and instrument packages spaced along the path of totality. They began training for this event by observing a total eclipse that crossed Indonesia in 2016 at five sites along its path.

Each site will produce more than 1,000 images during those approximately 2 minutes of totality in each area, with a resulting dataset of an unprecedented 90 minutes of continuous, high-resolution images detailing the Suns inner corona a region of the solar atmosphere typically challenging to image.

Not only are citizen scientists playing a critical role in this data collection it couldnt happen without them this overall project represents an incredible opportunity to excite and inspire future scientists as so many of these volunteers and students are just getting introduced to science. This is one of the best features of this total solar eclipse!

Thinking beyond the eclipse

But here at NSF we cant focus on any event in isolation. We are always looking at a bigger picture and how we can increase what we know about our universe.

In 2020, one of our agencys biggest undertakings will come to fruition as the NSF Daniel K. Inouye Solar Telescope (DKIST) comes online on Haleakala in Maui. It will be the largest, most powerful solar telescope in the world, sometimes described as the Swiss Army knife of solar telescopes because of the number and flexibility of the tools attached to it to enhance how we collect data about the sun, our nearest star. Although it is a telescope, it will seem more like a microscope on the sun as it provides new, significantly more detailed imagery than weve been able to obtain previously. Additionally, DKIST will be able to observe the solar corona with special instruments even when total solar eclipses are not in the offing.

This is truly the kind of science and technology that only NSF support can achieve: state-of-the-art technology that yields groundbreaking discoveries and pushes forward the frontiers of what we can learn about our universe.