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Eclipses inspire awe and bring people together to observe a stunning celestial phenomenon, but these cosmic events also allow scientists to unravel the mysteries of the solar system.
During the total solar eclipse on April 8, when the moon will temporarily obscure the face of the sun from view for millions of people in Mexico, the United States and Canada, multiple experiments will take place to answer some of the biggest unresolved questions about the golden sun easier to understand. sphere.
NASA will launch high-altitude sounding rockets and WB-57 aircraft to investigate aspects of the Sun and Earth that are only possible during a solar eclipse. The efforts are part of a long history of efforts to gather valuable data and observations when the moon temporarily blocks the sun’s light.
Perhaps one of the most famous scientific milestones associated with a solar eclipse occurred on May 29, 1919, when a total solar eclipse provided evidence for Albert Einstein’s theory of general relativity, which the scientist first systematically described in 1916, according to NASA.
Einstein had suggested that gravity is the result of the warping of time and space, disrupting the structure of the universe. For example, Einstein proposed that the gravitational influence of a large object such as the Sun could bend the light emitted by another object, such as a star nearly behind it, making the object appear slightly further away from the perspective of the soil. A scientific expedition to observe stars from Brazil and West Africa, led by English astronomer Sir Arthur Eddington during the 1919 solar eclipse, revealed that some stars indeed appeared to be in the wrong place, confirming Einstein’s theory.
The finding is just one of many scientific lessons learned regarding eclipses.
During the 2017 solar eclipse that crossed the US, NASA and other space agencies conducted observations using eleven different spacecraft and two high-altitude aircraft.
Data collected during that eclipse helped scientists accurately predict what the corona, or the Sun’s hot outer atmosphere, would look like during eclipses in 2019 and 2021. Despite the high temperatures, the corona looks fainter than the bright surface of the sun, but it is similar to a halo around the sun during a solar eclipse, with most of the sunlight blocked by the moon, making it easier to study.
Why the corona is millions of degrees hotter than the actual surface of the Sun is one of the enduring mysteries about our star. A 2021 study uncovered some new evidence showing that the corona maintains a constant temperature despite the Sun going through an eleven-year cycle of decreasing and increasing activity. The findings were possible thanks to more than a decade of eclipse observations, NASA said.
Although the sun has been quieter during previous eclipses, this year it is reaching the peak of its activity, the so-called solar maximum, offering scientists a rare opportunity.
And during the solar eclipse on April 8, citizen scientists and teams of researchers were able to make new discoveries that may expand our understanding of our corner of the universe.
Sending rockets to a solar eclipse
Observing the Sun during eclipses also helps scientists better understand how solar material flows from the Sun. Charged particles, known as plasma, create space weather that interacts with an upper layer of Earth’s atmosphere called the ionosphere. The region acts as a boundary between Earth’s lower atmosphere and space.
Energetic solar activity released by the Sun during solar maximum could disrupt the International Space Station and its communications infrastructure. Many satellites and radio waves in low Earth orbit operate in the ionosphere, meaning dynamic space weather affects GPS and long-distance radio communications.
Experiments to study the ionosphere during the solar eclipse include high-altitude balloons and a citizen science survey inviting the participation of amateur radio operators. Operators at different locations will record the strength of their signals and how far they travel during the eclipse to see how changes in the ionosphere affect the signals. Researchers also conducted this experiment during the October 2023 annular solar eclipse, when the moon did not completely block sunlight and the data is still being analyzed.
In another repeated experiment, three sounding rockets will take off sequentially from NASA’s Wallops Flight Facility in Virginia before, during and after the solar eclipse to measure how the sudden disappearance of sunlight affects Earth’s upper atmosphere.
Aroh Barjatya, professor of engineering physics at Embry-Riddle Aeronautical University in Daytona Beach, Florida, leads the experiment, called the Atmospheric Perturbations around the Eclipse Path, which was first performed during October’s annular solar eclipse.
Each rocket will eject four science instruments the size of a soda bottle within the path of totality to measure changes in the temperature, particle density and electric and magnetic fields of the ionosphere, about 60 to 300 miles above the ground.
“Understanding the ionosphere and developing models to help us predict disruptions is crucial to ensuring our increasingly communications-dependent world functions smoothly,” Barjatya said in a statement.
The sounding rockets will reach a maximum altitude of 260 miles (420 kilometers) during flight.
During the 2023 annular solar eclipse, instruments on the rockets measured sharp, instantaneous changes in the ionosphere.
“We saw the disruptions that could affect radio communications in the second and third rockets, but not during the first rocket before the peak of the local eclipse,” Barjatya said. “We are super excited to launch them again during the total solar eclipse, to see if the disruptions start at the same altitude and if their size and scale remain the same.”
Floating above the clouds
Three different experiments will fly aboard NASA’s high-altitude research aircraft, known as WB-57s.
The WB-57s can carry nearly 10,000 pounds (4,082 kilograms) of scientific instruments up to 60,000 to 65,000 feet (18,288 to 19,812 meters) above the Earth’s surface, making it the workhorse of the NASA Airborne Science Program, said Peter Layshock, manager of NASA’s WB-57 High Altitude Research Program at the Johnson Space Center in Houston.
The advantages of using WB-57s are that a pilot and an equipment operator can fly above the clouds for approximately 6.5 hours without refueling within the eclipse’s totality path that extends over Mexico and the US, providing a continuous and unobstructed view is possible. Due to the planes’ flight path, the instruments will remain in the shadow of the moon longer than on the ground. Four minutes of totality on the ground equates to six minutes of totality on the plane, Layshock said.
One experiment will also target the ionosphere using an instrument called an ionosonde, which works like a radar by emitting high-frequency radio signals and listening to the echoes as they bounce off the ionosphere to determine the number of charged particles hitting the ionosphere. contains to measure.
The other two experiments will focus on the corona. One project will use cameras and spectrometers to reveal more details about the temperature and chemical composition of the corona, and to record data on large eruptions of solar material from the Sun, known as coronal mass ejections.
Another project, led by Amir Caspi, a principal scientist at the Southwest Research Institute in Boulder, Colorado, aims to capture images of the eclipse from 50,000 feet (15,240 meters) above the Earth’s surface, in the hopes of spying on structures and details within the Earth’s surface . middle and lower corona. Using high-speed and high-resolution cameras, which can take images in visible light and infrared light, the experiment will also look for asteroids orbiting in the sun’s glare.
“In the infrared, we don’t really know what we’re going to see, and that’s part of the mystery of these rare observations,” Caspi said. “Each solar eclipse gives you a new opportunity to expand on things, taking what you learned from the last solar eclipse and solving a new piece of the puzzle.”
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