Featured Post from University of Delaware

The science of leap day

Feb 29, 2024

3 min

The arrival of a leap year brings with it myths, legends and superstitions about its origin. John Gizis, professor of physics and astronomy at the University of Delaware, takes part in a Q&A to share the truth and science behind this “extra” day added to the Gregorian calendar every four years.

Why do we have leap day?

Unfortunately, the amount of time the earth takes to go around the sun is not exactly 365 days. It’s off by about ¼ of a day each year.

It would be hard to have a calendar for 365 ¼ days. When was the extra day added to the calendar?

Julius Caesar introduced the Julian calendar in 46 B.C., which added one extra day every four years. Of course, the year is not exactly 365 ¼ days either, so after a while, that extra time built up. Pope Gregory XIII established the Gregorian calendar [the current calendar] in 1582 to correct the fact that the calendar had gotten off by about 12 days, enough that it was noticeable.

How was it noticeable?

The seasons were gradually shifting, so that what we think of as summertime in the northern hemisphere had gradually become more like autumn. The shortest day of the year is Dec. 21. Basically, the shortest day of the year drifted and eventually was in early December.

How did they institute the reforms?

First, they skipped a couple of weeks, so they returned to the original calendar lining up with the sun and stars as it’s supposed to. Then they instituted a couple of rules to keep this from happening again. Leap year happens in years divisible by four, but every 100 years, there is not a leap year. However, every 400 years, you do have a leap year. This happened in the year 2000. And the next time it will happen most of us won’t be around — 2100 will not be a leap year.

What would happen if the extra day had not been introduced?

If we didn’t have it at all, we would be off by ¼ of a day every year. The seasons would completely shift through the calendar and anything that ties to the seasons would be affected, like farming. It would create havoc with the time to plant and to harvest crops, for example. You also would lose the meaning behind sayings such as “April showers bring May flowers.”

Multiply the 2,000 years since it was introduced by ¼ day per year, and that would be 500 days we would have shifted over history. In the northern hemisphere January would have become summer, then gone back to being winter, then shifted off again.

Does adding the extra day make up the difference exactly and keep the astral year in sync with the calendar year?

Yes, but this relates to a bigger issue. Astronomers want time to match up so that the positions of the stars match up year after year. Because the length of day changes slightly over time, astronomers sometimes would like to add an extra “leap second” to keep the stars in sync with our time system. But adding a second is an annoyance for computer and tech systems.

Did you know that people born on leap day are sometimes called “leaplings?” According to Google, in 2020, there were about 5 million people with Feb. 29 birthdays. Do you think they have any advantages or disadvantages to being born on this day?

No, I didn’t know that, and I know someone who refused to be induced on that day because she didn’t want confusion for her child, although I think it might be cool. After all, in this day and age, everyone always knows how old they are.

To set up an interview with Gizis, visit his profile and click on the contact button.

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John Gizis

Professor, Physics and Astronomy

Prof. Gizis focuses his research on improving the understanding of stars and brown dwarfs (failed stars).

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Jun 1, 2026

7 min

UD English professors reveal 2026 beach reads, tying summer picks to big themes in today’s culture

When summer rolls around, the best beach reads do more than just pass the time—they somehow capture what everyone’s talking about right now. That’s the vibe behind University of Delaware’s professor-picked list: books that are fun to sink into, but also surprisingly sharp about the world we’re living in. Think big feelings, messy relationships, culture shifts, and the kind of stories that make you look up from the page and go, “Yep, that tracks.” "There Is No Antimemetics Division" By qntm A Reddit novel turned print bestseller, "There Is No Antimemetics Division" is a surreal horror story that follows an X-Fileish government division fighting aliens whose battlefield is the human mind. How do you fight an enemy whose existence you cannot remember? – Siobhan Carroll, Associate Professor "The Briar Club" By Kate Quinn I'm a big fan of Kate Quinn. Her books never disappoint. Her writing is wonderful and captivating, and the voices and characters are authentic. This book, set in the 50s, is a post-war reflection on a group of tenants in a boarding house who, over food (recipes included!), become friends and navigate McCarthyism, conspiracies and fear. It is historical fiction written to remind us that history repeats itself. – Christine Cucciarre, Professor "Guido Brunetti mysteries" By Donna Leon I've gotten completely hooked on these mysteries set in Venice. Fans will tell you the best is the fifth book in the series, "Acqua Alta," but be sure you read the first book to meet the characters! – Emily S. Davis, Director of Graduate Studies "When We Cease to Understand the World" By Benjamin Labatut An English professor recommending a book detailing the lives of physicists, scientists and mathematicians? Yes! History, heady concepts, madness, melancholy and beautiful prose come together in a haunting way. – Viet Dinh, Associate Professor "Dungeon Crawler Carl series" By Matt Dinniman What if you smushed role-playing video games/tabletop games with The Running Man? Plus, there's a sassy cat who talks! – Lowell Duckert, Associate Professor "Just Kids" By Patti Smith I've recently read "M Train" by Patti Smith, and now I'm looking forward to reading the book for which she won the National Book Award. Smith's memoirs can be impressionistic, but they often come down to some unexpected detail or some ongoing longing. If you know her music, you can sometimes hear it in the background, or you can spot those moments in her life when music would almost necessarily emerge as a great force gathered by her authentic approach to life. She's one of those writers who can change how you look for and find what most matters to you, how you look for and embrace your own soul. – John Ernest, Chair in English "Prairie Fires: The American Dreams of Laura Ingalls Wilder" By Caroline Fraser I loved reading the "Little House" books as a child. It seemed like a life full of adventure and love, even through "The Long Winter." But this biography of author Laura Ingalls Wilder reveals a life full of struggle and loss behind the calico dresses and the fiddle lullabies. Caroline Fraser won the 2018 Pulitzer Prize for "Prairie Fires," using unpublished manuscripts, letters, diaries, and land and financial records to pull back the pioneer spirit curtain and show readers the reality of life on the prairie. – Dawn Fallik, Associate Professor "The School for Good Mothers" By Jessamine Chan Warning: Do not bring this book to the beach without plenty of sun screen, because you will not put it down and that might make YOU a candidate for enrollment in The School. Second Warning: The book is compelling precisely because it will make you mad and freak you out. My wife gave it to friends as a Mother's Day present, and every mother who read it could relate. – Peter X Feng, Associate Professor "Audition" By Katie Kitamura This book has been on my bedside table for months now, just waiting for the semester to end. I am a sucker for books that shift perspective in the middle (see also: Susan Choi's "Trust Exercise"). – Peter X Feng, Associate Professor "The Road to Tender Hearts" By Annie Hartnett You might not expect a book that features domestic violence, children being orphaned and a 63-year-old man still pathetically dependent on his ex-wife to be funny. But I laughed out loud multiple times—and had some tears as well—as I read this novel! Follow the adventures of PJ, two children from his town, and a death-predicting cat as they road trip across the country. "The Road to Tender Hearts" was the best book I read all year! – Jill Flynn, Professor "The Stories of John Cheever" By John Cheever One of the finest collections of short fiction ever published. Witty, magical, often devastating portraits of people navigating mid-century New York. – McKay Jenkins, Cornelius Tilghman Professor of English "Vacationland: True Stories from Painful Beaches" By John Hodgman This book is a collection of nonfiction essays by John Hodgman (Daily Show writer and "Judge John Hodgman" podcast and The NY Times Magazine column). It is laugh-out-loud funny in a very self-deprecating, Gen X way. – Matthew Kinservik, Professor "Cloud Cuckoo Land" By Anthony Doerr This is one of the best novels I've ever read. Ever. It follows three stories set in very different times and places (15th-century Constantinople, 21st-century Idaho, and the not-too-distant future on a spacecraft headed to a new planet that will support human habitation). It's a book about the value of books and human storytelling. The stories eventually get braided together in moving and surprising ways. Amazing. – Matthew Kinservik, Professor "The Wilderness" By Angela Flournoy Have you wondered how your friendships in your early 20s might follow you into middle age? "The Wilderness" focuses on the friendships between four women: Desiree, Monique, Nakia and January from 2008 until 2027, when they are in their early 40s. They support one another through marriage, divorce, career anxiety, loss and a persistent set of questions about who they each want to be in the world and the lives they want to live. "The Wilderness" is told from many perspectives and details how culture, place, habits, friendships and childhood experiences combine to make and remake our adult lives. – Davy Knittle, Assistant Professor "Kin" By Tayari Jones "Kin" is about two motherless girls from Louisiana who find themselves as grown women on two very different paths, looking to other mother figures along the way. The writing is beautiful and engaging! I could not put this book down. I truly fell in love with all of the characters, and even the locations come alive. – Meg McGuire, Associate Director of First-Year Writing "How to Solve Your Own Murder" By Kristen Perrin This truly is a cozy mystery about a woman called Frances Adams—a resident of the moody Castle Knoll. When Frances is a teenager, she encounters a fortune teller who portends Frances's murder. Frances then spends most of her life sort of obsessively surveilling everyone around her, trying to figure out who will kill her. When she does die, her great niece Annie is surprised to learn that the late Frances has left Annie her entire estate, even though they have never actually met. When Annie arrives in Castle Knoll and at the estate, she follows in her great aunt's footsteps by holding all of the town's quirky characters at arm's length while she tries to discover who killed her late great aunt. This is an easy-breezy read, even if it does include a murder mystery at the center. Perfect for a day at the beach. Best of all, if you fall in love with the characters and the place, it's part of a series of three books, so you can keep going! – Cathryn Molloy, Professor "The Order of Time" By Carlo Rovelli You could read any Rovelli book, really—I am reading the one on the birth of science at the moment— but this is the one that drew me in. He merges a physics/science‒centered approach to time with a human/experienced‒centered view of it, which I just cannot get enough of. It is beautifully written, at times verging on poetic, while also bringing in a lot of the information and knowledge I seem to have skipped over as a terrible science student. It's joyful and intense and meditative. And yes, this is what I read for fun! – Amish Trivedi, Assistant Professor "The Season of Styx Malone" By Kekla Magoon Two young Black boys in small-town Indiana fall under the spell of Styx Malone, a mysterious new kid who arrives for the summer and stirs things up by persuading them to pursue their biggest dreams and breaking a few rules along the way. I collect multicultural kids books and stumbled across this one six years ago. It captured me because it celebrates family and friendship, depicts young people with rich interior lives, and mixes in a little mystery and humor. There's something sweet and down-home about it. It's a refreshing little respite from, well, everything ... – Délice Williams, Associate Professor To speak to the professors more about what makes these books the perfect summer reads, email mediarelations@udel.edu.

May 14, 2026

4 min

New clues about how earthquakes work

University of Delaware researcher Jessica Warren helped uncover evidence that sections of fast-moving underwater faults may act like “brakes,” controlling the occurrence of big earthquake events on transform faults. Warren can discuss what the findings, released today in the journal Science, mean for earthquake science and future modeling. Situated along a stretch of the equator in the Pacific Ocean, between Indonesia and Central America, the Gofar transform fault is one of the fastest moving faults on Earth — cruising along the seafloor at about 140 millimeters per year. This is over four times faster than the San Andreas fault is moving in California. “Geologically speaking, it's like looking at a moving Acela train next to a SEPTA train on the tracks,” said Warren, a professor of earth sciences at UD. Researchers know that the Gofar transform fault line has experienced a magnitude 6 earthquake about every five to six years over the last three decades. It’s been studied extensively, as these earthquakes occur at the same places along the fault and at the same intensity, time after time. What’s been unknown, until now, is why parts of this fault experience many small microshocks leading up to a main earthquake rupture, then shut down, while other parts of the fault are quiet before the big event and then experience many aftershocks. Now, a multi-institutional team of researchers, including UD’s Warren, reports that sections of the fault without large magnitude earthquakes actually act like brakes in a fast-moving car, controlling the occurrence of big earthquake events on transform faults. This finding is in contrast with currently accepted models of earthquake behavior. The team includes researchers from UD, Indiana University, Woods Hole Oceanographic Institution, Scripps Institution of Oceanography at UC San Diego, the U.S. Geological Survey, Boston College, Western Washington University, the University of New Hampshire and McGill University. In the study, the researchers analyzed two zones along the Gofar transform fault they say have stopped about 15 magnitude 6 earthquakes over the past 30 years. The study findings will inform globally what’s known about how faults and earthquakes behave, at sea and on land. Warren's contributions include leading the initial field research at sea in 2019 on the R/V Atlantis and interpreting results throughout the project, with a focus on connecting the earthquake observations to how rocks in the fault fracture and distort during an earthquake. Why were you studying the Gofar transform fault, in particular? Warren: Geoscientists want to understand faults and earthquakes because they are obviously a big hazard on land. The rocks that make up the seafloor are simpler than those found on land, providing a more controlled space to study earthquakes, despite the challenges of doing research underwater. If you want to understand how faults build up stress and then release it (and where), the Gofar transform fault is amazing, because it experiences earthquakes at reliable intervals of five to six years. This is a lot more regular than any other fault. In 2019, I led a research cruise on the R/V Atlantis that deployed 51 seismometers two miles down on the seafloor to detect these small events. We were able to compare the results of our measurements from 2019 to 2020 to an experiment conducted by my colleague Jeff McGuire on the same fault in 2008. The similarities in the two datasets brought us to the realization that fault sections without large magnitude earthquakes control the overall occurrence of big events on transform faults. When we had that observation in 2008, that might have been a one-off, but getting back this new data and seeing such similar behavior was a new insight into what's happening in the fault. How does that tell you about how earthquakes occur on land? Warren: On land, people spend a lot of time looking at how rainwater and groundwater move in a fault system, and how that influences the behavior of the fault. In the oceans, we have an unlimited amount of water. Once the rock cracks, the water is going to get in there. Being able to look at how a fault changes through the earthquake cycle — which we've now measured most of on this one fault — can help us understand what is universal about how faults work, and how rock friction works. And one of the big players is water. That's why the rock samples that my lab works on matter. Fault structure is another thing that we've been trying to understand. We know from on land that some parts of a fault are linear, while other parts have lots of strands and maybe contain more fractures and that, if you start putting water in the picture, this can limit or change how water moves into the system. Now, we have these very high-resolution maps of the seafloor, where we can see, for the first time, where the fault itself is. One of the next things we want to understand is how fluid gets into the fault, and then how friction in a fault changes when water is there. Why is this important? Warren: The next step is to translate the understanding that we've gained from this specific fault to understanding how faults behave in general. This is the longer path to really understanding earthquake hazards. It's not going to change our hazard models tomorrow, but hopefully it will in the decades to come. To reach Warren directly and arrange an interview, visit her profile and click on the "contact" button. Interested reporters can also email MediaRelations@udel.edu.

May 8, 2026

4 min

Survey says: Senior leaders are using AI, but they could use more direction

Over the years, study upon study has shown that senior leaders are slower to adapt to new technology – email, the Internet and social media – than younger employees. That’s not necessarily so with AI, according to the University of Delaware’s Saleem Mistry. Mistry, associate professor of management at UD's Alfred Lerner College of Business & Economics, recently conducted a survey of more than 200 university alumni, 75% of which had more than 16 years of professional experience. He found that senior leaders are actively adopting AI to solve their biggest challenges. However, they are doing so largely without structured support or guidance. Here are four findings from Mistry's survey that shows how AI is actually being used at the top. Senior Leaders Are Overwhelmingly Self-Taught Mistry said his most glaring finding is the gap between high AI adoption among senior leaders and the near-total absence of formal corporate support. Although a majority use these tools, they are almost entirely self-taught, which highlights visible opportunity that organizations aren’t really steering the AI conversation for leaders: • High usage. 62% of all senior leaders surveyed use AI tools "regularly" or "occasionally" in their work. • Training gap. Of those users, an overwhelming 80% report their organization provides "Never" or only "Sometimes" (mostly never) adequate training. Mistry said this shows that leaders from VP level down are using tools like ChatGPT and Copilot informally to keep up with heavy workloads, without any real organizational guidance. The stakes are high. In the survey, a vice president of legal was using AI for compliance tasks and a manager of three was using it for performance reviews, both with no formal training. “These are senior leaders handling sensitive work while essentially figuring it out on their own,” Mistry said. There is a clear ladder of AI use Leaders are not using AI randomly. There is a clear progression in how they use it, moving through three levels. • Tier 1 (The Drafters) This is the most common starting point. Leaders use AI to improve writing and communication. They draft emails, shape documents, and refine tone. As one Director of Product put it, it helps him "polish phrasing" and adjust tone and voice. • Tier 2 (The Synthesizers) At this stage, leaders use AI to manage information overload. They summarize meetings, condense documents, and pull together research so they can keep up with large volumes of input. As one leader managing a team of 200 said, "Being a leader requires attention in a variety of areas. AI helps me manage the vast amounts of information I need to consume." • Tier 3 (The Architects) Here, leaders move beyond writing and summarizing. They use AI to automate parts of their work. This includes building agents, creating custom GPTs, or designing tools that track work and performance. One leader managing 300 people said, "It will eliminate half or more of my overhead." Managers and individual contributors use AI for different reasons People managers and individual contributors (IC) are using AI for very different reasons based on their roles. • For people managers, their main challenge is scale. They are overloaded with communication and administration, so they use AI to reduce noise and keep up. They lean heavily on summarization and tone adjustment tools. • For project leads and ICs, their focus is output. They use AI to produce work faster, including drafting content, building decks, writing code, or generating ideas. This difference reflects their jobs. One group is trying to keep up, the other is trying to produce more. It also shows that AI is not a single-use tool. Its value depends on the problem it is being used to solve. This difference reflects their jobs. One group is trying to keep up, the other is trying to produce more. It also shows that AI is not a single-use tool. Its value depends on the problem it is being used to solve. Resistance to AI is mostly intentional Among the 38 percent of leaders who do not use AI, resistance is usually not based on lack of awareness. It falls into three groups: • The Ethical Objectors. Some avoid AI due to concerns about its broader impact. • The Quality Skeptics. Some do not trust the output and feel it is not reliable enough for important work. • The Blocked. Some are not allowed to use AI due to company policy. Mistry concludes that there is a clear overall pattern: Leaders are using AI in practical ways, but mostly without structured support or guidance. “If it feels like you are figuring this out as you go without much help from your organization, that is consistent with what most leaders are experiencing,” Mistry said. To connect directly with Mistry and arrange an interview, visit his profile page and click on the "connect" button. Interested reporters can also email MediaRelations@udel.edu.