Listening for crickets isn’t the only way you can help NASA conduct research during the total solar eclipse passing across much of North America on April 8—you can also lend your smartphone camera to the cause. The agency is calling on anyone within the upcoming eclipse’s path to totality to participate in its SunSketcher program. The program will amass volunteer researcher data to better understand the star’s shape. To participate, all you need is NASA’s free app, which uses a smartphone’s camera coupled with its GPS coordinates to record the eclipse. But why?
The sun looks simply spherical in many photographs and renderings, and in the sun if you happen to briefly glance at it during the day—an emphasis on “briefly,” of course. But thanks to what’s known as oblateness, this isn’t ever really the case. A rotating spheroid will oblate when its centrifugal force generates enough inertia to slightly flatten it out into a more irregular, elliptical shape. Within the solar system, Earth, Jupiter, and Saturn all also display oblateness, but the sun has some unique characteristics affecting how it oblates in particular.
According to NASA, the sun’s oblateness “depends upon the interior structure of the rotation, which we know from sunspot motions to be latitude-dependent at least.” Astronomers also think gas flows accompanying the sun’s magnetic activity and convection can create “transient distortions at a smaller level.” The upcoming total solar eclipse will provide astronomers an opportunity to better understand all this in the sun, but to make that happen, NASA wants you to harness the moon.
Earth’s natural satellite can serve as a valuable research partner in measuring the sun’s oblateness. This is due to a phenomenon known as “Baily’s beads,” which are the tiny flashes of light during an eclipse that occur as…
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