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Eclipses inspire awe and bring people together to observe a dazzling celestial event, 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 sun’s face for millions of people in Mexico, the United States and Canada, numerous experiments will be conducted to better understand some of the biggest unresolved questions about the golden star. sphere.
NASA will launch sounding rockets and WB-57 high-altitude aircraft to conduct research on aspects of the sun and Earth that are only possible during the eclipse. These efforts are part of long-standing initiatives to collect invaluable data and observations when the moon temporarily blocks sunlight.
Perhaps one of the most famous eclipse-related scientific milestones, the total solar eclipse that occurred on May 29, 1919, provided evidence for Albert Einstein’s theory of general relativity, which the scientist first systematically described in 1916, according to NASA.
Einstein proposed that gravity was the result of time and space warping, distorting the fabric of the universe. As an example, Einstein proposed that the gravitational influence of a large object such as the Sun could deflect the light emitted by another object, such as a star, immediately behind it, causing the object to appear slightly further away from Earth’s perspective. A science expedition to observe stars in Brazil and West Africa during the 1919 eclipse, led by British astronomer Sir Arthur Eddington, revealed that some stars did indeed appear in the wrong place, confirming Einstein’s theory.
The finding is just one of many scientific lessons learned about eclipses.
During the eclipse that passed over the United States in 2017, NASA and other space agencies conducted observations using 11 different spacecraft and two high-altitude aircraft.
Data collected during the eclipse helped scientists accurately predict what the corona, or the sun’s hot outer atmosphere, would look like during eclipses in 2019 and 2021. The corona, despite its dazzling temperatures, is apparently dimmer than the sun’s bright surface, but when most of the sunlight is blocked by the moon, it appears like a halo around the sun during an eclipse, 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 clues showing that the corona maintains a constant temperature even as the sun experiences an 11-year cycle of decreasing and increasing activity. The findings were made possible thanks to more than a decade of eclipse observations, according to NASA.
The Sun, which was quieter in previous eclipses, is reaching the peak of its solar maximum activity this year, presenting scientists with a rare opportunity.
And during the eclipse on April 8, teams of citizen scientists and researchers may make new discoveries that will potentially improve our understanding of our corner of the universe.
Sending a rocket into the eclipse
Observing the sun during eclipses also helps scientists better understand how solar energy flows from the sun. Charged particles known as plasma create space weather, which interacts with the upper layer of Earth’s atmosphere called the ionosphere. The region acts as a boundary between the Earth’s lower atmosphere and space.
The energetic solar activity released by the sun during solar maximum can interfere with the International Space Station and its communications infrastructure. Many satellites in low Earth orbit and radio waves operate in the ionosphere; This means that dynamic space weather has an impact on GPS and long-distance radio communications.
Experiments to study the ionosphere during the eclipse include high-altitude balloons and a citizen science initiative that invites the participation of amateur radio operators. Operators in different locations will record the strength of their signals and how far they traveled during the eclipse to see how changes in the ionosphere affect the signals. The researchers also conducted this experiment during the annular eclipse in October 2023, when the moon did not completely block sunlight, and the data is still being analyzed.
In another repeated experiment, three sounding rockets will launch in succession from NASA’s Wallops Flight Facility in Virginia before, during and after the eclipse to measure how the sudden loss of sunlight affects Earth’s upper atmosphere.
Aroh Barjatya, a professor of engineering physics at Embry-Riddle Aeronautical University in Daytona Beach, Florida, leads the experiment, called Atmospheric Perturbations Around the Eclipse Path, which was first performed during October’s annular solar eclipse.
Each rocket will launch four soda-bottle-sized scientific instruments into the path of totality to measure changes in the temperature of the ionosphere, particle density, and electric and magnetic fields from about 55 to 310 miles (90 to 500 kilometers) above the ground.
“Understanding the ionosphere and developing models that help us predict disturbances is crucial to ensuring the smooth functioning of our increasingly communications-dependent world,” Barjatya said in a statement.
Sounding rockets will reach a maximum altitude of 260 miles (420 kilometers) during flight.
During the annular eclipse in 2023, instruments on the rockets measured sharp and sudden changes in the ionosphere.
“We saw perturbations in the second and third rockets that could affect radio communications, but this was not seen during the first rocket before the peak of the local eclipse,” Barjatya said. “We are very excited to launch them again during the total eclipse to see whether the perturbations start at the same altitude and whether their size and scale remain the same.”
Soaring above the clouds
Three different experiments will be flown on NASA’s high-altitude research aircraft known as WB-57s.
WB-57s can carry approximately 9,000 pounds (4,082 kilograms) of scientific instruments to altitudes of 60,000 to 65,000 feet (18,288 to 19,812 meters) above the Earth’s surface, making it the most powerful of the NASA Airborne Science Program, said Peter Layshock, NASA Airborne Science Program manager. . WB-57 High Altitude Research Program at Johnson Space Center in Houston.
The benefits 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 spanning Mexico and the United States, providing a continuous and unobstructed view. The planes’ flight path means the instruments will be in the moon’s shadow longer than they would be on the ground. Layshock said four minutes of integrity on the ground is closer to six minutes of integrity on the plane.
An experiment will also focus on the ionosphere using an instrument called an ionosonde, which acts like a radar by sending out high-frequency radio signals and listening to echoes reflected off the ionosphere to measure the number of charged particles it contains.
The other two experiments will focus on corona. One of the projects will use cameras and spectrometers to reveal more details about the temperature and chemical composition of the corona, as well as capture data on large explosions 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, peering into structures and details on the planet. middle and lower corona. The experiment, which uses high-speed and high-resolution cameras that can capture images in visible light and infrared light, will also search for asteroids orbiting in the sun’s glare.
“We don’t really know what we’ll see in the infrared, and that’s part of the mystery of these rare observations,” Caspi said. “Every eclipse gives you a new opportunity to expand on what you learned from the last eclipse and solve a new piece of the puzzle.”
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