Should the weather gods grant their blessing, a celestial display for the ages will darken the skies over much of the US from Texas to Maine on Monday, giving tens of millions of people a view of a rare phenomenon known as “the Great American Eclipse“.
It will be another 20 years until the next one total solar eclipse can be seen anywhere in the contiguous US, providing an added incentive for many who live outside the 115-mile-wide “path of totality” to travel in and the moments of twilight, stillness and a sudden drop in temperature that the event will bring, to experience.
Such is the interest in the eclipse that numerous cities and states in the US and Canada have a emergency in anticipation of enormous crowds; energy providers in Texas are warning of a significant, albeit temporary loss in power generation; and many schools, offices and public buildings in the 15 states that will experience totality will close.
Other dark clouds gathering over the show are more literal. Rain forecast for the southern and central parts of the US for Monday afternoon could mean that the best viewing will be in the east and through Nasa’s live stream or television coverage.
But astronomers say for those lucky enough to watch in person, the eerie darkness of a total eclipse, punctuated by the spectacular, ever-changing light show of the moon passing directly across the face of the sun, is an unexpectedly intense and ethereal experience.
That’s why Nasa advise eclipse watchers that, as well as looking out for bright planets and stars in the darkened sky, and viewing the beautiful image of the darkened sun through eclipse safety glasses, “It’s worth taking a look at the people around you steal. Many people have a deep emotional response when the sun goes into totality.”
John Gianforte, professor of space science at the University of New Hampshire and director of its observatory, agrees.
“I’m a scientist, and yes, there is data, there are facts, there are observations and discoveries, papers to write, all of that. But I’ve seen five solar eclipses and, really, they’re like nothing else,” he said.
“For the 2017 eclipse, my family and I, and some friends from my childhood, were in Tennessee. We had beautiful weather in the mountains, and it was the most emotional heavenly event I have ever seen, my wife and my children, their friends and my grandchildren, all screaming and shouting about something happening in the sky.
“I get emotional when I think about it. It was an incredible experience as a parent, a friend, a grandfather, truly one of the most moving moments I can remember in my entire life. It was just fun to watch, and people who have seen one understand why people get emotional and make a big deal about traveling to watch a total solar eclipse.”
What makes this year’s eclipse so special, Gianforte says, is its size. Nasa estimates more than 31 million people live in the path of totality, nearly three times as many as were in the narrower and shorter path of 2017’s coast-to-coast eclipse, and another 4 to 5 million are expected to travel in, which bring with them an expected $1.5 billion tourism bonanza.
In addition, the time of totality – the period in which the moon completely blocks out the sun – will be much longer. Along the middle of the path, it will vary from about four and a half minutes in Eagle Pass, Texas, where the eclipse begins around 1:27 p.m. CT after crossing the Mexico border, to nearly three and a half minutes in Maine, where it leaves the US and moves eastward Canada to the Atlantic Ocean.
Totality will also cross Oklahoma, Arkansas, Missouri, Illinois, Kentucky, Indiana, Ohio, Pennsylvania, New York, Vermont and New Hampshire, plus small parts of Tennessee and Michigan. Nowhere outside the path will experience a total eclipse, but a partial eclipse of decreasing percentage will be visible in almost all of North America, determined by proximity.
“After people see a total solar eclipse, the first question they ask is when is the next one. Well, this is the next one, it cuts across a densely populated and accessible road, and a lot of big cities, so it’s generating a lot of interest,” Gianforte said.
“Many of the kids who saw the 2017 eclipse and had their interest spurred are in high school, or maybe college, and are taking advantage of another opportunity. It’s another 20 years until the next one, and that’s a long time to wait.”
Meanwhile, Nasa maintains that the eclipse is not only a breathtaking visual spectacle, but also an opportunity for a bit of real science. The space agency, in collaboration with Florida’s Embry-Riddle Aeronautical University, will fire rockets into the moon’s shadow during the eclipse to study how the Earth’s upper atmosphere is affected by the brief dimming of sunlight.
It also enlisted an army of citizen scientists to help with a series of projects explore the effects and mysteries of a solar eclipse. Among them is Eclipse Megamoviein which the public is invited to use DSLR cameras to capture images of the solar corona during the total eclipse, or to help analyze them following it.
“Solar physicists don’t know how much of the sun’s mass is leaving the sun,” Laura Peticolas, project director at California’s Sonoma State University, told Space.com. “Total solar eclipses provide information to the solar community that cannot be provided in any other way.”
