By Lisa Potter, science writer, University Marketing and Communications

On Monday, Aug. 21, staff, students and faculty will begin orbiting closer to the University of Utah for the first day of classes, slowly heading to the campus that will be the center of their universe until winter break.

That same morning, the Earth and moon will begin orbiting closer toward perfect alignment, until the moon blocks our view of the sun, casting a shadow across the entire United States that we Earthlings will enjoy as the Great American Eclipse.

On Aug. 21, 2017, millions of Americans will look to the east, with appropriate protective gear, to take part in the elaborate celestial dance. Although a tide of Utahns will head north to see the full eclipse, those in Salt Lake City can witness the moon block more than 90 percent of the sun. The J. Willard Marriott Library will host a solar-eclipse-viewing party from 10 a.m. to 12 p.m. to help Utes on campus view the event safety. Attendees will have a chance to win prizes throughout the event, including a new telescope, Starbucks gift cards, “Star Wars” and “Star Trek” movies and more.

The library’s Rare Books Department will feature a hands-on display of astronomical treasures, from 1,000-year-old books from Ptolemy to first editions of Galileo and Einstein and beyond. This will be a great opportunity for students to touch and feel books that served as the foundation for the study of astronomy.

“I’m hoping we’ll have a blast,” says Jordan Hanzon, marketing and public relations assistant at the library and mastermind behind the eclipse extravaganza. “My aim is to help new and returning students discover the library as a place to come not only to study, but to have fun as well.”

Solar safety swag

The eclipse will begin at 10:13 a.m., reach its maximum at 11:33 a.m. and end at 12:59 p.m. The library will hand out free solar eclipse glasses to the first 3,000 attendees, thanks in part to a partnership and donation from the Department of Physics & Astronomy. Volunteers from the department will be on hand to answer your questions.

Hanzon will give away solar-themed goodies, such as Capri Suns and Sun Chips, as well as other space-related prizes. Get there early. The library’s Facebook event has nearly 4,000 responses from campus and community folk alike. Early birds will be rewarded with more than solar swag; they’ll avoid missing the event due to traffic.

“I’m not exactly sure how many people will be there, but I definitely recommend utilizing the TRAX services unless you get here very early for a parking spot,” recommends Hanzon.

Remember to protect yourself while watching the eclipse. The rules are the same as staring at the Sun any other day — without safety precautions, you can permanently damage your eyes.

“Our retinas don’t have many pain receptors. You can do a lot of damage and not feel pain,” says Inese Ivans, assistant professor in the Department of Physics & Astronomy. “The only safe way to look directly at the sun, even when it is partially eclipsed, is by using special-purpose solar filters, such as ‘eclipse glasses,’ handheld solar viewers, or welder’s glasses with shade No. 12 or higher.”

To view the eclipse safely, you need to wear glasses that block 99.99 percent of the sun’s visible light. Regular sunglasses won’t do it.

“The real deal will only let you see 10 photons out of every 100,000 photons that would otherwise reach your eyes,” says Ivans. “Never look at the sun with binoculars or a telescope without an expert who has the necessary filters and equipment, otherwise you are risking permanent blindness.”

Be very skeptical of eclipse merchandise — many swindlers are producing fake glasses that will fail to protect your eyes.

The solar eclipse

The Great American Eclipse is the first eclipse to cross the U.S. from coast to coast in 99 years. You’ll have to wait until 2045 to see an eclipse cross the continental U.S. again.

Solar eclipses happen when the moon crosses in front of the sun and casts a shadow onto the Earth’s surface. Have you ever used your hand to shield your eyes on a sunny day? That’s basically what the moon is doing. Just like your hand needs to be at the right distance and angle to shade your eyes, so too does the moon have to be at the perfect distance and angle to block the sun. Because the moon and Earth have tilted orbits, and constantly change their distances from each other, solar eclipses are rare events.

“When the sun is eclipsed, you are literally in the shadow of the moon,” says Paul Ricketts, director of the South Physics Observatory at the U. “Depending on where you are located, you will see different views of the eclipse.”

To see the moon totally eclipse the sun on Aug. 21, you need to be in the so-called path of totality — a dramatic, metal-band-sounding phrase that describes the darkest portion of the moon’s shadow. Areas such as Idaho Falls, Idaho, and Grand Tetons National Park, Wyoming, are in the path. People outside the path of totality will see a partial eclipse. In Salt Lake City, the sun will be more than 90 percent obscured by the moon at its peak. All 50 states will see at least a partial eclipse, however the farther someone is from the path, the less eclipsed the sun will be.

“For most people, this is a once in a lifetime event,” says Ricketts. “So, no matter where you are, in the morning hours of Aug. 21, 2017, look east with the proper protection.”

Check out the video at the top of the story for animations, viewing options, and cool solar features to look for during the Great American Eclipse.