On Aug. 21, millions of Americans will be witness to a total solar eclipse, the first viewable in the United States since 1979.
Although a total solar eclipse can be seen somewhere in the world every 18 months, it can only be viewed from a single spot once in 375 years. The last total solar eclipse observed within the United States occurred in the year 1979. As reported by The Week, this will be the first solar eclipse “since 1918 to be visible from coast to coast.”
A total solar eclipse occurs when the Earth, moon, and sun are in complete alignment with one another. The moon’s orbit brings it between the Earth and the sun, casting a shadow that falls across the Earth. “The Great Solar Eclipse of 2017” is only visible in America, and it crosses through 14 states. Ethan Siegel, an astrophysicist, states that “More than 12 million people will get to experience totality without ever leaving their homes.”
Approximately 75 million people live within 200 miles of the eclipse’s path of totality. Large crowds are expected. Military and emergency response teams are preparing for the influx of people who are excited to see a “once in their lifetime” phenomenon.
A total solar eclipse is a gradual process that begins at the moment the moon appears to touch the sun. NASA helio-physicist Mitzi Adams talks about what everyone can expect to see in the following phases of this year’s solar eclipse.
“This leads to the partial phase when it looks like someone is taking increasingly large bites from the sun. Next is the actual eclipse itself, when the sun is totally covered by the moon. Some animals react. Cows may start walking toward the barn. Crickets start chirping.”
A large amount of scientific data is generally collected during a solar eclipse, and this one is no different. Wired reported that, while millions of viewers watch from below, NASA has readied two 1960s vintage WB-57F jets to fly the skies. These planes are not merely for show, they will be flying at 50,00 feet and recording data and video footage. NASA plans to fly the jets in tandem, on either side of the moon’s shadow, which will stretch the video footage of totality to seven minutes.
Solar scientists can, and have, simulated eclipses through the use of a coronagraph. However, nothing can compare to the total solar coverage provided by the moon’s shadow. NASA has flown telescopes during an eclipse in the past, but the lead NASA researcher on the project, Amir Caspi, states that “this will be the highest quality observation of this type made to date. The resolution and the frame-rate we’ll be able to achieve will provide new insights into how the sun works.”
NASA will fly the jets equipped with cameras called AIRS/DyNAMITEs, which will not only record data but also transmit it for live broadcast on NASA’s website. The footage will help answer why the outer edges of the sun are hotter than the surface, as well as potentially revealing the existence of nanoflares. Caspi discusses the importance of solar study during an eclipse.
“Studying things like these two factors and the solar flares and the coronal mass ejections we can also see during eclipses teaches us about weather hazards.”
NASA is funding 11 research projects in total, a majority of which are taking place on the ground. The event dubbed “The Great American Total Solar Eclipse” will stretch 70 miles from Oregon to South Carolina. Where will you be on August 21, 2017?
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