What scientists hope to learn during the eclipse on 12 August

During a total eclipse, the Moon will cover the bright solar disc, and the corona — the Sun’s rarefied outer atmosphere — will become visible around it. Under normal conditions, its faint glow is lost against the background of the star’s bright light.

The path of totality will pass through Greenland, Iceland, the Atlantic Ocean, Spain and a small part of Portugal. In most areas, total darkness will last for less than two minutes, whilst the longest duration will be approximately two minutes and 18 seconds.

Details

One of the Sun’s greatest mysteries concerns the temperature of its atmosphere. The visible part of the star is significantly cooler than the corona, which heats up to nearly a million degrees.

During the eclipse, NASA’s cameras will capture the corona across several wavelengths of visible and infrared light. Researchers hope to track rapid changes within it, study solar prominences and come closer to explaining how the outer atmosphere is energised.

The aircraft will track the Moon’s shadow

Some of the equipment will be installed on NASA’s WB-57 high-altitude aircraft. It will climb to a height of approximately 15 kilometres and fly along the path of the Moon’s shadow.

Four cameras capable of taking at least 20 images per second will be operating on board. The flight will allow the observation time of the corona to be extended to almost three minutes and will avoid the clouds that might obscure the eclipse for ground-based telescopes. At high altitude, the instruments will also be able to detect some of the infrared radiation that is normally absorbed by the lower layer of Earth’s atmosphere.

The eclipse will help identify the source of the solar wind

The Sun constantly ejects a stream of charged particles into space – the solar wind. During intense disturbances, huge clouds of plasma can be carried along with it.

Scientists hope to link the movement of matter in the corona with the subsequent formation of the solar wind. Such observations will help us better understand how processes near the Sun give rise to phenomena capable of affecting satellites, spacecraft and the work of astronauts.

Even before the eclipse, experts at the European Space Agency are producing a computer simulation of what the solar corona is expected to look like on 12 August.

When the Moon blocks out the Sun, scientists will compare the calculations with actual images. This will allow them to check how accurately the models reproduce the shape of the corona and the arrangement of magnetic structures.

The main difficulty lies in the fact that only one side of the Sun is visible from Earth at any one time. Researchers therefore have to reconstruct a complex three-dimensional picture of its magnetic field from two-dimensional images. The eclipse will provide a rare opportunity to verify the accuracy of such a reconstruction.

Why this is important for Earth

Changes in the Sun’s magnetic field can lead to powerful eruptions of material. When these reach Earth, they can cause bright auroras, disrupt satellite operations and pose a greater risk to people and equipment in space.

More accurate models will not prevent solar storms, but they can help provide earlier warnings of their approach. This extra time will allow satellite operators and other services to prepare for the possible consequences.

Balloons to study Earth’s atmosphere

Some experiments will focus not on the Sun, but on the Earth’s atmosphere’s reaction to the sudden disappearance of light.

In Iceland, scientists plan to launch 80 balloons before, during and after the eclipse. They will investigate how quickly the lower layer of air cools and how its thickness changes.

In Spain, six balloons fitted with panoramic cameras will film the movement of the lunar shadow and measure ozone levels. During the 2024 eclipse, ozone levels temporarily decreased, and scientists now want to find out whether this effect will recur at a different time of day and in a different season.

Will the eclipse reveal all the Sun’s secrets?

A single eclipse is not enough to learn how to predict solar flares with absolute accuracy or to definitively explain the heating of the corona.

The Sun is constantly changing, so every eclipse reveals its atmosphere in a new state. The main value of the observations on 12 August lies in the opportunity to collect rare data, verify existing calculations and improve future scientific experiments.

How to observe the eclipse safely

During the partial phases, you must not look at the Sun without special glasses or a certified solar filter. Ordinary sunglasses do not protect your eyes.

You may only remove your eye protection for a short time during the total phase, and only in locations within the path of totality. Cameras, binoculars and telescopes require separate filters fitted in front of the lens.

Source

This material is based on observation programmes by NASA and the European Space Agency. A total solar eclipse will take place on 12 August 2026.