The August Solar Eclipse Left Fascinating Clues About Hidden Atmospheres and Vital Satellites

This year, eclipse fever swept over Americans eager to see a cross-country phenomenon as the moon blotted out the sun, leaving a brilliant halo of light hanging over a sudden midday darkness. Plenty of scientists also caught eclipse fever, but their excitement was a little more targeted: The alignment of Earth, moon and sun offers a precious window in which they can gather measurements that are usually impossible to take.

Total solar eclipses are actually common, occurring about once every 18 months. But this particular eclipse was unusual— throughout most of its duration, it was visible over American land. For amateurs, that means it was much cheaper to travel to than many eclipses, but for scientists, it meant they could watch the eclipse from land without blinking for about an hour and a half all told.

And four months later, we're finally starting to see some results from the huge range of projects that aimed to tap into the opportunity offered by the eclipse.

12_26_total_solar_eclipse Scientists used specialized, airborne telescopes to study the sun during the eclipse. NASA/SwRI/Amir Caspi/Dan Seaton

One of those projects used telescopes perched on board two converted airplanes to chase the sun's outermost layer, the corona, for a total of about seven minutes. The corona usually isn't visible, but it's all that's left to see after the layer that produces most of the sun's light, the photosphere, is blocked by the moon. The shaky footage those telescopes produced is now letting scientists study giant magnetic waves that ripple out through the corona. The corona was a popular target during the eclipse, and other projects looked at changes in temperature and speed within the corona.

Other projects were faster to get results, like a project that sent high-altitude balloons up to study eclipse changes to the atmosphere. That data told scientists that the very bottom of Earth's atmosphere sinks during an eclipse the same way it sinks overnight. Within a few months, that same project could also tell us how well equipped terrestrial bacteria are to colonize Mars, which turns out to look quite like Earth's stratosphere but darker—precisely what happens during an eclipse.

Read more: How the Moon Was Formed: Scientists Blame Giant Impact With a Rock Smaller Than Mars

Another type of experiment looked at how changes in the charged particles of the upper atmosphere affected communications. That's a model of sorts for less predictable changes, like those caused by solar flares, which means the August observations could help make satellite-based communications more reliable.

And of course, as Newsweek reported Monday, the eclipse also produced a phenomenon scientists had never seen before—wake-like bow waves rippling out across the planet's upper atmosphere. Chances are, even that discovery will be eclipsed by what we have left to learn from August's incredible celestial alignment.

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