'Most awesome natural spectacle': Scientists, society excited for rare total eclipse visible from Pa.

Apr. 8—JOHNSTOWN, Pa. — A hypothesis exists that a stone carving of overlapping concentric circles at Ireland's Loughcrew Cairns, which date back to approximately 3300 B.C., may be the oldest surviving record of a solar eclipse.

An eclipse is calculated to have occurred in that region in 3340 B.C.

Witnessing a shadow being cast on the land during the day, as the moon passed between the Earth and sun, would have been amazing, terrifying and worthy of permanent commemoration. And it would have been unpredictable in those days.

Five millennia later, scientists and society in general have known well in advance that a total solar eclipse will occur Monday in North America.

The prediction is precise — the total eclipse phase will occur in the northwestern tip of Pennsylvania around 3:15 to 3:20 p.m., with the exact time varying somewhat depending on the location.

The full sequence of events — from the first hint of darkness in the sky until the lighting returns completely to normal — will last from around 2 to 4:30 p.m.

That amount of detail is part of an ever-changing understanding of the celestial phenomena that included ancient Babylonian astronomers, living in what is now Iraq and parts of Syria and Iran, being credited as the first to track eclipses.

A solar eclipse that occurred on May 3, 1375 B.C., in the ancient port city of Ugarit, Syria, was recorded on a clay tablet that still exists.

Eclipses are also believed to have been mentioned in Homer's "Odyssey" and numerous ancient religious texts.

"We're always learning more," said Amanda Iwaniec, director of theater experiences at Carnegie Science Center in Pittsburgh. "The initial questions and the initial observations that people saw with eclipses helped to build that understanding and helped to really start to put time and energy around it. People thought, 'What is this?' Then we have technologies that help us to understand science. We make hypotheses. ...

"We're constantly examining the things we think we know and using the information that's current to make changes. I think what's really exciting about science is that we have that adaptive reaction to be able to question and to learn more.

"We're going to be learning a lot from this eclipse."

Along with science and mathematics, seeing a total eclipse — with the sun's corona glowing like a ring of fire in the sky — can be, in the words of Stephen Lindberg, an adjunct professor in the University of Pittsburgh at Johnstown's Energy and Earth Resources Department, "awe-inspiring" and can even cause some people to have "an epiphany."

"I tell the students, in terms of natural phenomena that you can see on the Earth or in space, a total eclipse has to be the most awesome natural spectacle occurrence that you can witness," said Lindberg, who still recalls the inspiration he got from watching an eclipse as a child in the 1960s on Long Island, New York.

"I've seen volcanic eruptions, been in small earthquakes. Years and years ago, I was in a small F1 tornado I witnessed. But nothing compares to a solar eclipse.

"A total solar eclipse is really awesome. That's the only way to describe it."

'Long path of totality'

The path of totality — where the full solar eclipse will be visible — will go through Mexico, from Texas to Maine, and across southeast Canada. It will pass over Austin, Dallas, Indianapolis, Cleveland, Buffalo and Montreal, and pass near several other major metropolitan areas.

"The eclipse that's coming up is very exciting because it has a very long path of totality that goes through a good chunk of the United States," Iwaniec said. "It goes through or near a lot of big cities. What that really does is it gives an opportunity for many people to be able to view it in totality if they choose.

"I think one of the most exhilarating and cool things about it is we won't really see another one for another 20 years in the same kind of vein."

Pennsylvania's Crawford, Erie, Mercer and Warren counties will experience the total eclipse. Four state parks — Presque Isle, Erie Bluffs, Pymatuning and Maurice K. Goddard — will be in the path.

The remainder of the commonwealth will experience an eclipse magnitude ranging from 99% to 88.65%.

"We're going to see (a) partial (eclipse in the Johnstown area)," Lindberg said. "The sun's going to be about 96%, 97% covered up.

"It's still going to be light outside. It's probably going to be like twilight here. You'll notice it getting darker, but it's not going to be getting completely dark. The sun is extremely bright, and even if a little bit of the sun is showing around the moon, it's probably going to look like 7:30 or 8 o'clock at night."

The most recent total solar eclipse that occurred in the United States happened on Aug. 21, 2017. There won't be another anywhere in the country until Aug. 23, 2044.

Ancient Babylonians meticulously tracked the heavens generation after generation, including recording Saros cycles lasting 223 lunar months (18 years and 111/3 days, or 6,585.3 days) that are used to put eclipses into different periods. They reached the point of being able to predict eclipses.

But such detailed scientific understanding did not exist throughout the world's general population during that time.

In modern days, the upcoming eclipse has been taught in classrooms and science centers across the nation for days, weeks, months and years.

One lesson Lindberg has shared with his Pitt-Johnstown students is that a lunar eclipse — during which the Earth was positioned between the moon and sun — recently occurred, although it received very little attention, being overshadowed, so to speak, by the upcoming solar eclipse.

"The neat thing about eclipses, too, is they always occur in pairs," he said. "That's part of the Saros cycle. Whenever you have a solar eclipse of any type — so if you have a total solar eclipse, a partial solar eclipse, an annular solar eclipse — whenever you have a solar eclipse, there will always be a lunar eclipse within two weeks before or after it.

"That's why we had an eclipse Monday night (March 24 into March 25). So there was an eclipse of the moon (on that) Monday night, and now, two weeks later, we have a solar eclipse. That is because the moon follows this regular pattern."

Lindberg encouraged students to watch the eclipse on Monday, using the proper protective eyewear.

Meanwhile, Carnegie Science Center is planning a special day of programming for people who cannot make it to the path of totality. Eclipse viewing will take place from 1:59 p.m. until 4:30 p.m, with the maximum totality occurring at 3:17 p.m.

There will be other eclipse-based lessons. Live NASA feeds from spots along the path of totality will be shown in Buhl Planetarium.

"It's going to be a fun, community, carnival atmosphere," Iwaniec said.

She said the eclipse programming is an example of the museum's mission to "spark that curiosity and provide a lifelong opportunity for learning."

"This is just one very public, nationwide event that I think will put a lot of science and curiosity in the forefront of people's thinking," Iwaniec said. "But everyday we make those connections for kids."