In less than two weeks, parts of South America will be visited by the moon’s shadow, as a total solar eclipse blots out the sun for just over two minutes. This follows a similar event on July 2 last year, when a midafternoon darkness descended on Chile and Argentina as a total solar eclipse cast a shadow on the landscape.

In an unusual coincidence, Chile and Argentina will both find themselves in the path of totality for the second time in 531 days, with the Dec. 14 event stretching 600 miles south of its predecessor. This time, however, the ongoing global coronavirus pandemic is likely to complicate or altogether prevent viewing of the spectacle by eclipse aficionados, with thousands canceling their plans to journey south amid surges of the virus in Europe, the United States and elsewhere, with travel restrictions in place.

Argentina remains closed to travelers from the United States until further notice, along with most international residents, while Chile just recently announced plans to open its borders the week before the eclipse. Travelers to Chile will be allowed to enter the country only through the airport in Santiago, and they will be required to have a negative coronavirus test and proof of medical insurance that is valid abroad.

For those who can make it, however, this year’s show promises to be spectacular — weather permitting. The path of totality spans from south-central Chile east-southeast through the arid plains of Argentina, crossing through a diverse landscape that features active volcanoes, the Andes Mountains and the Patagonian Desert.

A total solar eclipse occurs when the moon passes between Earth and the sun, casting a shadow within which daylight on Earth is momentarily extinguished.

The path of totality

The eclipse will begin over the south-central Pacific Ocean about 90 minutes before reaching the shores of South America, where totality will commence on Mocha Island a minute before 1 p.m. on Dec. 14. The shadow, 56 miles wide, will sweep rapidly east-southeast.

Temuco, a city of 220,000, is the first major city in line for totality, but only the south side of town will enjoy the show. Areas north of Cerro Neilol, a hill in the northern half of the city that offers panoramic views of the skyline, will witness only a partial solar eclipse. Areas less than three miles to the south will experience about a minute of totality.

Then comes Villarrica, home to about 45,000. The popular lakeside resort town lies directly on the centerline of totality, and should have about 2 minutes, 9 seconds of peak eclipse viewing. Modest Airbnbs are running at between $200 and $500 a night now as astrotourists prepare to congregate there and in neighboring Pucón.

Chile has instituted a “Paso a Paso,” or “step-by-step” program, which categorizes coronavirus travel and commerce restrictions in varying municipalities on a 1-to-5 scale. Level 3 demarcates “preparation,” which entails nightly quarantines from midnight to 5 a.m., inter-communal travel, and the allowing of social gatherings of up to 25 indoors or 50 outside.

The eclipse will bring about a sudden nightfall atop three volcanoes along the Chilean-Argentine border, including the Villarrica volcano, where the Villarrica National Park is selling tickets to campers on a first-come, first-served basis.

Thereafter, the shadow slides into Argentina, where weather prospects are better but international admission largely impossible. Only small communities dot the path of totality before the shadow exits offshore into the Gulf of Saint Matias and eventually the open Atlantic.

Those within the path of totality can expect a deep twilight to set in within a matter of just 30 seconds or a minute, transforming the early afternoon into a dusky scene with pastel hues of orange about the horizon and azure overhead. More spectacular than the abrupt darkening will be the emergence of the corona — the sun’s vaporous atmosphere that traces the sun’s magnetic field with visible light. Tendrils of milky-white luminosity highlight the corona, protruding millions of miles into space.

A stunning view of the solar corona

Over the years, scientists have used eclipses as one of the best possible opportunities to study the sun’s corona. Even the best instruments and technology aboard satellites can’t replicate or resolve the corona with the exquisite level of fine detail visible from the ground during a total solar eclipse. Some scientists work to predict what the corona will look like during totality, producing striking three-dimensional models.

Predictive Science, a San Diego-based company specializing in visualizations of the solar atmosphere, recently released its simulation of what the upcoming eclipse may look like. They did the same for the August 2017 and July 2019 total solar eclipses with relatively accurate results. By using a detailed digital map of the sun’s estimated magnetic field and time on NASA supercomputers, the team was able to model how the field might evolve into mid-December — and what form the visible light of the corona might take.

This year, increased activity and storminess on the surface of the sun could make for a more dynamic, roiling corona, with loops and prominences. Predictive Science is calling for three or four such excursions of the solar corona, radiating off the sun into the darkness of the shadow-induced somber.

Last year’s eclipse featured a less-exciting corona since solar activity was minimal, making this year’s likely to be even more spectacular.

And the best part for those who venture into the path of totality? The date of the eclipse coincides with the peak of the Geminid meteor shower, meaning totality could be punctuated by green meteors streaking across the sky.