The total solar eclipse on August 21, 2017 is the first of its kind to go coast-to-coast across the continental United States in nearly a century. While the partial eclipse will start earlier and end later, the total eclipse will travel from Oregon to South Carolina in a speedy 93 minutes. Its narrow, 70-mile-wide, path of totality will begin at Lincoln Beach, OR at 10:15 a.m PDT (1:15 p.m. EDT) and continue through Idaho, Wyoming, Montana, Nebraska, Iowa, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, and North Carolina, before ending in Charleston, SC at 11:48 a.m. PDT (2:48 p.m. EDT).
For Americans in the path of totality, the wondrous spectacle, when the moon will obscure the sun leaving behind its breathtaking corona, will last anywhere from one minute to a maximum of 2 minutes and 41 seconds. However, the fortunate researchers aboard two WB-57F jets chasing the moon’s shadow, or umbra, will enjoy the phenomenon for three and a half minutes. As you may have guessed, the team led by Amir Caspi of the Southwest Research Institute in Boulder is not being sent for a pleasure cruise but to conduct some important experiments for NASA.
The airplanes, which have been retrofitted with two telescopes, one to observe the sun’s visible light and the other to monitor Mercury’s infrared light, will fly parallel to one another and maintain a 70-mile distance between them to straddle the moon’s shadow on Earth. Cruising at an altitude of 50,000-feet, where the cloud-free skies will be twenty to thirty times darker than that on the ground, the researchers hope to capture detailed images of the corona, an aura of plasma that surrounds the sun.
The team hopes the pictures will enable scientists to better understand why the corona is millions of degrees hotter than the sun, which sports a relatively cool temperature of 10,000°F (5,600°C). One theory suggests it is the accumulated impact of the numerous micro explosions, or nanoflares, that are believed to regularly emanate from the sun. However, since the flares are too small to be observed under normal conditions, scientists have been unable to verify the theory. “People have made observations of 10 million degree plasma in the corona, and that kind of heat is suggestive of nanoflare heating,” Caspi says. “Nanoflares are a theory, and we think they exist, but we don’t really know for sure.”
In addition, the researchers also hope to use the high-definition photographs to better understand how the sun’s corona manages to remain relatively untangled, despite the constant movement. Even when the plasma loops and arcs do get a little unruly, the corona restores order by tossing them out as solar flares or a mass ejection. According to Caspi, “Solar flares can cause radio interruptions on Earth, but even bigger dangers come from coronal mass ejections. That’s when the sun throws off billions of tons of material, and the particles can come toward Earth. When that happens, it can knock out satellites, it’s a hazard for astronauts, and it can knock out power systems here on the ground.” An understanding of how the corona remains organized will enable scientists to predict coronal mass ejections.
The infrared telescopes fitted on the two jets will help create the first-ever thermal image of Mercury, the closest planet to the sun, which will be more visible in the darkened skies. The scientists believe that studying the variation of temperatures across this usually hard-to-observe planet’s surface will help reveal its soil composition and provide some insight into its formation.
Though this is the most exciting experiment, it is just one of the 11 being funded by NASA to take advantage of the total solar eclipse. While most are focused on the sun, the agency is also using the event to investigate how the sudden reduction of light and temperature affects weather, vegetation and animal behavior on Earth.
Whether the “Great American Eclipse” will reveal any solar secrets remains to be seen. However, it will definitely be a thrilling event to watch so mark your calendars, and more importantly, be sure to wear special eclipse glasses or hand-held solar viewers to avoid damaging your eyes. And don’t forget to share your experience with us by writing your comments below.
Resources: BJInsider.In NASA.gov,NPR.org