March 25, 2024

Jennifer Carter, assistant professor of physics Jennifer Carter, assistant professor of physicsAstronomers and spectators alike are preparing their telescopes and protective eyewear to view the upcoming total solar eclipse set to unfold on April 8. Jennifer Carter, assistant professor of physics at Susquehanna University, has been looking forward to the celestial show for years.

“It’s a big moment for me, an opportunity when I’ll get to share astronomy with my community,” Carter said. “I’m very excited because I’ve never seen an eclipse this close to totality before, and an eclipse like this will not occur again in our part of the world during my lifetime.”

A solar eclipse happens when the moon blocks the light of the sun and creates a shadow that passes over parts of Earth, Carter explained. A total solar eclipse occurs somewhere on Earth about every 12 to 24 months, but the area can only be viewed in totality by less than 1% of the Earth’s surface. That area varies depending on the distance of the moon from the Earth’s surface and the topography of the part of the Earth over which the shadow of the moon lands, Carter said.

According to NASA, the upcoming total solar eclipse will be visible in the U.S. along a 100-plus-mile track stretching from Texas to Maine. This is known as the path of totality.

The exact length of a total solar eclipse depends on your position on Earth and the position of the sun and moon. For this eclipse, the sun will be completely covered in the path of totality for between 3 and 4.5 minutes. The place with the longest totality during the eclipse — 4 minutes and 28 seconds — will be in Torreón, Mexico. The complete eclipse, from when the moon starts to cover the sun to when it completely moves beyond it, will take around 2.5 hours, Carter said.

In the path of totality sky will darken as if it were dawn or dusk, Carter said. Animals and plants will react as if it were nearing nighttime — flowers will close and chickens may go to roost, she said, while temperatures will drop as much as 10 degrees. During this time, viewers in the path of totality will have the rare opportunity to see the sun’s corona, or the outermost part of the sun’s atmosphere that is usually hidden by the bright light of the sun’s surface.

In Selinsgrove, about 94% of the sun’s surface will be hidden by the moon. The best viewing of the eclipse will start at 3 p.m. and run until about 3:45 p.m., Carter said. These are the times between which the temperature can change, as well as shadows and color. The decrease in light will be like an overcast day, Carter said. The sky may appear to change to a silvery color, or maybe a slight purple.

2024 versus 2017

Image of the solar corona during a total solar eclipse in 2017. Image of the solar corona during a total solar eclipse in 2017.The last time a total solar eclipse was visible in the U.S. was in 2017. There are a few key differences between that event and the upcoming one.

First, this year’s eclipse will be seen by more people. According to NASA, the path of the upcoming eclipse is almost twice as wide as it was during the eclipse in 2017 because the moon is currently closer to the Earth in its orbit.

In 2017, the path of totality ranged from about 62 to 71 miles wide. During the April eclipse, the path over North America will range between 108 and 122 miles wide.

Additionally, the upcoming eclipse will last longer than it did in 2017. Seven years ago, the longest period of totality was 2 minutes, 42 seconds. For the upcoming eclipse, as Carter noted, totality will last more than 4 minutes.

Finally, the upcoming eclipse is occurring during a time of heightened solar activity. In 2017, the sun was nearing solar minimum, when there are fewer giant eruptions from the sun. But during the 2024 eclipse, the sun will be in or near solar maximum, when the sun becomes more active. Viewers of the eclipse will have a better chance of seeing more of what the sun has to offer, like prominences, which appear as bright, pink curls or loops coming off the sun, coronal mass ejections, which is a large eruption of solar material, or sunspots, which are dark areas of magnetic activity.

Carter has been looking to the skies since she was a child when her grandfather, an amateur astronomer, first showed her his telescope. She’s been particularly interested in the stars, and her current research describes how to estimate light incident on exoplanets.

“Events like this are a great opportunity to get people excited about solar science as we approach solar maximum,” she said.

The next total solar eclipse that will be seen from the contiguous United States will be on Aug. 23, 2044.

The meaning of solar eclipses in religion

Matt Duperon, associate professor of religious studies and coordinator of the Asian studies program Matt Duperon, associate professor of religious studies and coordinator of the Asian studies programHistorically, solar eclipses have held significance in various religious and cultural contexts, often as omens or warnings, both good and bad.

From Buddhism and Hinduism to Judaism and various indigenous religions, ancient civilizations often viewed eclipses with fear and believed the events foretold of impending doom or displeasure from the gods. They believed the eclipse required special prayers, acts of service or even sacrifice in response.

“Astronomical phenomena like eclipses were widely believed in ancient China to indicate something about the disposition of heaven to the human government,” said Matt Duperon, associate professor of religious studies and coordinator of the Asian studies program at Susquehanna. “That is, they were often taken as signals from heaven that the current ruler had lost or gained favor with the cosmic forces that influenced human affairs from afar.”

The ancient Chinese, Duperon said, used the term rishi 日食 to refer to an eclipse. It remains in modern Chinese and refers to something consuming or devouring the sun.

“There’s a lot of folklore about celestial beasts, usually a dragon or dog, swallowing the sun during an eclipse, so allegedly people would make a lot of noise to try and frighten it away and leave the sun alone,” Duperon said. “It’s important to note, however, that early Chinese astronomy was already quite advanced, so literate people probably didn’t really believe that’s what was happening.”

Further advances in science have long given us the real reasons behind eclipses, though many religions still view the astronomical events as a time of transformation and renewal and a reminder of the interconnectedness of life on Earth to the cosmos.

How to safely view a solar eclipse

The main rule for viewing an eclipse is not to look at the sun directly without proper filters. Looking directly at the sun, even for a few seconds, can cause permanent or long-lasting retinal burns. Here are Carter’s tips for viewing the April eclipse safely.

Eclipse glasses. Eclipse glasses or viewers work by using filters to dampen the intensity of the sun’s light to at least 1,000 times darker than ordinary sunglasses. First, check with your local library or museum to see if any are available. If not, you can purchase them online from retailers recommended by the American Astronomy Society. Eclipse glasses or viewers should state that the product meets the ISO 12312.2 or 12312.2-2015 international standard. The AAS also can tell you if your viewer makes the grade.

“I do not recommend using retailers not listed on the site due to the danger of counterfeit equipment,” Carter said.

Projection. If you don’t have eclipse-viewing glasses, Carter recommends using projection by casting an image of the sun onto a screen or the ground. Her favorite tool is called a box pinhole projector. You can learn how to build your own here.

More information on how to safely view the eclipse can be found from the AAS.