Solar eclipse coming April 8. Here is what you can expect in Green Bay

GREEN BAY – “Partial eclipse of the heart” isn’t nearly as satisfying to sing as the original lyric, but it’s catchy enough. Likewise, a partial solar eclipse isn’t nearly as awesome as a total solar eclipse, but it’s still pretty cool.

And while Brian Welsch, an associate professor of physics at University of Wisconsin-Green Bay who studies the sun, said it’s probably not worth it to drive somewhere for a partial eclipse, it’s a rare phenomenon that everyone should make it their business to see April 8. The next one won’t hit the continental U.S. for another 20 years, in 2044.

“If you live in some part of the country where it happens and don’t travel, you’re only going to really run into these every 20 or 40 years. That’s pretty rare,” Welsch said. “If you can get to the path of totality, go — but the partial is certainly interesting.”

The path of totality refers to the track of a total solar eclipse. Just 0.5% of the world population live in the 2024 path of totality, according to The Planetary Society.

Lucky for people in the Green Bay area who like driving, it takes around eight hours to drive to the path of totality — just keep in mind you’re not the only person doing this. Traffic to a total solar eclipse event can be a nightmare, to put it delicately, so plan in advance. (For example, the 2017 solar eclipse in Wyoming set a record as the most traffic the sparsely populated state has ever seen.)

People in Wisconsin won’t be able to see a total eclipse on April 8, but the partial eclipse will offer its own cosmic spectacle. The moon’s shadow is calculated to cover nearly 85% of the sun at its peak at 2:09 p.m. for Green Bay-area residents, slightly more if you’re in Madison and nearly 90% if you’re in Milwaukee.

If you’re not paying attention it might just feel like an average Wisconsin spring day, but eclipse enthusiasts will have several opportunities to appreciate the spectacle. So break out your pasta colanders, loosely woven straw hats, DIY skills and celestial wonder — there are plenty of ways to enjoy the partial eclipse this year.

What happens during a solar eclipse?

A simple explanation is that a solar eclipse occurs when the moon moves between the sun and parts of the earth, Welsch said. It requires the sun, earth and moon to be on the same orbital plane, and when that happens, the moon, in all its craggy glory, creates a shadow over the earth.

As the moon orbits the earth over the course of 29½ days, it goes through phases. While the poets are more inclined to write poems about crescent and waxing gibbous moons than they are about new moons, a solar eclipse can only happen during new moon, when the moon’s shadow over the earth perfectly blocks out the sun’s light.

Welsch said the conditions for a solar eclipse are favorable when the moon is on the same ecliptic line as the earth, which marks earth’s orbital path around the sun. The moon intersects this ecliptic line twice a month at points called nodes — which are either descending or ascending.

If the moon moves from below to above this ecliptic plane, it’s called an ascending node, which is the type of solar eclipse we’ll experience April 8. The solar eclipse from 2017 moved from north to south of the ecliptic plane, which is characterized as a descending node.

Fun fact: Our solar eclipses — and lunar eclipses for that matter — only happen by chance. Welsch explained that the moon had to settle just right in its orbit around Earth for the alignment to work out this way.

“That’s what we call a cosmic coincidence,” Welsch said.

How will the 2024 solar eclipse be different than the 2017 eclipse?

An estimated 215 million U.S. adults viewed the solar eclipse in 2017 when it passed from Oregon to South Carolina, according to NASA. Its path of totality ranged from 62 to 71 miles wide.

April’s path of totality is calculated to be a lot beefier than the 2017 solar eclipse, covering a range of 108 and 122 miles wide. This eclipse will travel across three North American countries, crossing from Sinaloa, Mexico into Texas, up to Maine and exiting over Quebec, Canada.

Astoundingly, Carbondale, Illinois, which is only 17.8 square miles long, will enjoy its second cosmic year in a row of being in the path of totality. Many Wisconsinites made the eight-hour-long mass exodus to Carbondale in 2017, and they’ll have a second opportunity come April.

“Carbondale has become the eclipse center of the U.S. for at least these two last events,” said Jim Lattis, director of the UW Space Place in Madison, the education and public outreach center of the University of Wisconsin-Madison Astronomy Department. Lattis added that the chances of a third encounter in 2044 are “pretty low.”

A chunkier shadow this year also means the path of totality will last longer. In 2017, the longest period of totality happened to also taken place in Carbondale, where it lasted two minutes, 42 seconds, according to NASA.

This year, totality will last more than four minutes in certain parts of the path. In an area about 25 minutes northwest of Torreón, Mexico, it’s expected to last four minutes, 28 seconds. By the time it gets to Texas, it’ll last four minutes, 26 seconds. Totality will last more than four minutes as far north as Economy, Indiana. Sorry, Carbondale — you can only wear so many crowns.

How rare are solar eclipses in the United States?

Typically, the Earth experiences a couple solar eclipses a year, said Lattis. But like the paradox of a tree falling in the desolate woods, if a solar eclipse happens in the middle of the ocean, did anyone really see it?

Most solar eclipses happen near the Earth’s two poles or completely across the oceans, Lattis said.

“To have one cross a major land mass — it’s not all that rare, but it feels rare to us, because all those things have to happen for that to work out,” Lattis said.

Take the recent number of total eclipses in the continental U.S. The last one took place seven years ago, in 2017. Prior to that, the only other solar eclipses in the 20th century happened in 1979 and 1970, breaking a nearly 100-year gap in the phenomenon.

Welsch was a kid when the 1979 eclipse passed through his home state of Kansas. His teacher didn’t let her students outside to witness it out of fear of kids staring directly at the sun.

“And I remember the newscaster saying that won’t happen again until 2017,” Welsch recalled, which felt like an impossibly long time. Little did he know he would become an expert in the field. He plans to go to Texas to see the total eclipse in April, making it his third time observing the spectacle.

Are partial solar eclipses still worth seeing?

It’s easy to simply not notice the partial solar eclipse if you’re outside the path of totality, Lattis said, but if you’re aware it’s happening, you can still have fun.

On a clear day, you can make little partial eclipse shadows rain down on walls and sidewalks using a pasta colander. Or you can interlace your fingers to view a series of PacMan-shaped shadows. You can poke holes in cardboard for the same effect.

Please remember though: In the same way you wouldn’t look directly at the sun on any given day, do not look at the sun directly during a partial solar eclipse.

But even if you’re eager to view a partial eclipse, the weather may break some hearts.

Green Bay has an average of 85 sunny days per year and another 102 days of partly cloudy days, according to National Climatic Data Center. And the chances of overcast in April are pretty high. As of this reporting, Accuweather forecasts showers on April 8, holding true to the April showers adage. (At least we can count on some May flowers, though.)

What are some fun facts about solar eclipses for my solar eclipse-themed dinner party?

Lattis is a historian of astronomy and even has a book coming out next year about the history of Wisconsinites contributions to the Cosmos called “Chasing the Stars: How the Astronomers of Observatory Hill Transformed Our Understanding of the Universe.”

Before we had a better understanding of space, humans had all sorts of ways they interpreted what on earth was going on during a solar eclipse.

Herodotus, a Greek historian active in the mid-400 BCE, wrote of a six-year battle fought in the early sixth century BCE between the Medes and the Lydians. Amid the bloodshed of one battle, the day suddenly turned to night, which both sides saw as admonishment from the Gods. The two sides called off the war and negotiated a peace treaty.

Scientists have a pretty firm grasp today of where and when this battle occurred by following astronomical calculations. The area of the battle, in modern-day Turkey, experienced a total solar eclipse May 28, 585 BCE, also known as the Eclipse of Thales.

“They were pretty startled, enough that while it had been important to kill each other before, now it was not good. So they just went home,” Lattis said.

Ancient Babylonians had a sophisticated relationship with astronomy. Their long astronomical records reliably predicted lunar eclipses, which work every time since lunar eclipses can be viewed across an entire hemisphere of the Earth as opposed to solar eclipses, which afford visibility to only a narrow strip of land, Lattis said.

Other ancient folklore suggested a celestial dragon gulped down the sun, but whether this was their literal interpretation or just a way to describe the phenomenon is anyone’s guess, Lattis said.

For lucky folks who venture to a total solar eclipse, you’ll be able to peek a rare viewing of the planet Mercury, which is normally only visible just before sunrise and just after sunset, Welsch said.

You’ll also be able to see the sun’s corona, the only time humans can ever see the crown of the sun with their naked eye. Coronal streamers, which are often featured in cartoon depictions of the sun, can sometimes be seen shooting out of the sun and are produced from solar wind stretching the sun’s magnetic field.

For more fun solar eclipse facts, Green Bay-area residents will have multiple opportunities to see Welsch give kid-friendly presentations about the April 8 event. Join him at one of two events from 1:30 to 2:30 p.m. March 23 and March 28 at the Brown County Central Library, 515 Pine St.

Source: Solar eclipse coming April 8. Here is what you can expect in Green Bay

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