At the American Geophysical Union (AGU) meeting on December 10 in Washington, DC, researchers presented initial results from National Aeronautics and Space Administration (NASA) experiments on the April 8 total solar eclipse.

This total solar eclipse spanned 18,000 km (11,185 miles) and stretched from Mexico to Canada in North America. It offered unprecedented opportunities for studying solar-terrestrial interactions. The research teams focused on corona behavior, ionospheric responses and atmospheric changes, collecting data for the further development of heliophysics.

Observable transformations in the solar corona

During the solar eclipse on April 8, the Sun’s corona showed significant structural changes and fluctuations in electrified plasma temperatures.

The Citizen CATE 2024 project captured over 47,000 images of polarized light, documenting corona magnetic field transitions and plasma flow patterns. The project compiles these images into a one-hour film. The film is expected to hit theaters in mid-2025 and will provide a visual analysis of these phenomena.

“The beauty of CATE 2024 is that we connect cutting-edge professional science with community participants from all walks of life,” said Sarah Kovac, project manager at Southwest Research Institute.

“The commitment of every single participant made this project possible.”

NASA’s high-altitude WB-57 aircraft observed the corona in the Fe-XIV wavelength range and detected plasma at about 1.8 million °C (3.2 million °F). Instruments documented intricate arc-like structures within the corona, although some images were blurred due to unexpected wing vibrations. Nevertheless, spectrometers provided highly precise data.

“The WB-57 is a remarkable eclipse observation platform that we plan to use for future eclipses,” said Shadia Habbal of the University of Hawaii.

Atmospheric Responses to Totality (Complete Eclipse Phase)

During the totality phase of the solar eclipse, when the moon completely covered the sun, community radio operators participating in HamSCI observed ionospheric shifts.

Data analysis of over 52 million observations showed that absorption of radio signals decreased at frequencies between 1 and 7 MHz, resulting in improved communications during the eclipse.

Interference occurred at frequencies above 10 MHz.

The analysis confirmed that the ionosphere temporarily rose during the eclipse and returned to normal afterward.

“The project brings amateur radio operators into the scientific community,” says Nathaniel Frissell, a professor at the University of Scranton.

“Their dedication to their craft made this research possible.”

Tropopause and atmospheric gravity waves

High-altitude balloon data from the Nationwide Eclipse Ballooning Project documented ripples in the atmosphere, known as gravity waves, caused by the eclipse. Instruments recorded perturbations in the tropopause that are similar to the atmospheric effects seen during sunsets.

“Half of the teams had little to no experience with ballooning before the project. But their hard work and research were crucial to this discovery,” noted Jie Gong, an atmospheric scientist at NASA’s Goddard Space Flight Center.

These results are consistent with previous theories suggesting that gravity waves are generated in the atmosphere by rapid changes in temperature and pressure triggered by sudden cooling during a solar eclipse.

A joint effort

More than 36,000 volunteers contributed to NASA’s solar eclipse research projects, including SunSketcher and GLOBE Observer. These citizen scientists collected 60,000 data points such as temperature fluctuations and solar phenomena, demonstrating the value of collaborative science.

As NASA’s Big Year of Heliophysics continues through December 2024, further analysis of the collected data promises deeper insights into the complex dynamics of the Sun’s influence on Earth.

References:

¹ Scientists share initial results from NASA solar eclipse experiments – NASA – December 10, 2024