LOS ANGELES (AP) — Math nerds and dessert enthusiasts unite to celebrate Pi Day every March 14, the date that represents the first three digits of the mathematical constant pi.
Representing the ratio of a circle's circumference to its diameter, pi is approximately equal to 3.14159 — but its digits go on forever. In school, you might have used it to calculate the area of a circle or the volume of a cylinder. But the applications of pi are endless and part of every corner of our world.
The holiday was created in 1988 by Larry Shaw, a physicist at the Exploratorium science museum in San Francisco.
“He had a very open and expansive view of the world and saw an opportunity with this number, mathematical concept, to invite people into the joy of mathematical learning,” said Sam Sharkland, program director of public programs at the museum, who worked with Shaw before he died in 2017.
While it began as a small staff celebration featuring pie, it soon turned into a grand procession where hundreds of visitors marched around the pi shrine, each carrying a digit. Attendees often show up early to claim their favorite digit for the parade. One woman who has the symbol tattooed on her neck comes every year and marches near the front with a pi flag, Sharkland said.
The celebration begins at 1:59 p.m., signifying the next three digits of pi.
Here are a few ways pi is being used on the cutting edge of science.
In Artur Davoyan's field of mechanical and aerospace engineering, pi is so fundamental that it would be hard to pinpoint one use case for it, he said.
Pi is part of “literally every single formula that you would use to do any calculation, like for spacecraft motion, for materials and how they work, or propulsion systems,” said Davoyan, a professor at the University of California, Los Angeles.
Anything that is round or has cyclical or repeating properties — such as radio waves — involves pi. Even squares or irregular blobs can be broken down into a series of progressively smaller circles and calculated using pi, Davoyan said.
Davoyan's research looks at how to create new propulsion systems to send spacecrafts more quickly to the far reaches of the solar system to gather and send back information to Earth. He pointed to NASA’s Voyager 1 and 2, which launched in 1977 but didn't reach interstellar space until 2012 and 2018.
To send a signal to those space probes, NASA must calculate Earth's exact position in orbit around the sun and design antennas for communication using pi. Then scientists use pi once more when receiving and breaking down complex signals that are being beamed back to Earth.
“Say aliens send something to us, something that we don’t know how to deal with,” Davoyan said. “So the very first thing that you would do, you would try to split it into simple functions... and turns out that when you do this operation, you will naturally have pis in it.”
Pi also comes up frequently when studying small amounts of fluids.
Dino Di Carlo, chair of the bioengineering department at the UCLA Samueli School of Engineering, conducts research that involves creating little particles out of polymers that act as tiny test tubes for cells. This is used as an important tool to examine cells closely and learn about their functions and what's inside them.
The pi constant is used in calculating how to form those droplets, surface tension calculations that define how droplets can break up, and how researchers can control the size of those volumes, Di Carlo said.
Di Carlo is using this technique to find antibodies — small proteins that fight diseases in your body — that could block signals put out by cancer cells.
Pi is also an important part of calculations when looking at how liquids flow through tubes and barriers. One example is when the fluid sample slowly flows sideways in a take-home COVID-19 test.
Di Carlo used these properties to devise a new test for Lyme disease that can be completed in 20 minutes, rather than days or weeks like previously.
“As an engineer and scientist, (pi) is just a part of life,” Di Carlo said. “Maybe I’ve taken it for granted.”
FILE - In this photo made with a long exposure, a SpaceX Falcon 9 rocket, with four private citizens onboard, lifts off from Kennedy Space Center's Launch Pad 39-A, Wednesday, Sept. 15, 2021, in Cape Canaveral, Fla. (AP Photo/John Raoux, File)
WASHINGTON (AP) — Anti-Muslim rhetoric from some Republicans in Congress intensified this week against the backdrop of the Iran war, with multiple lawmakers — including one who said “Muslims don’t belong in American society” — drawing condemnation from Democrats for their remarks but little pushback from GOP leaders.
The derogatory language has been percolating among Republican officials for months, often prominent when criticizing New York Mayor Zohran Mamdani, who is Muslim. But against the backdrop of the Iran war, a country with an overwhelmingly Muslim population, and attacks at a synagogue in Michigan and a college in Virginia, the tone sharpened this week.
“The enemy is inside our gates,” Alabama Sen. Tommy Tuberville wrote Thursday in response to a photo of Mamdani sitting on the ground during an iftar dinner at New York City Hall. The photo was juxtaposed with a picture of the Sept. 11 attacks.
Hours later, Tuberville doubled down: “To be clear, I didn’t ‘suggest’ Islamists are the enemy. I said it plainly.”
The rhetoric intensified Friday as GOP lawmakers responded to the attacks in Michigan and Virginia by urging a halt to all immigration into the United States. Some singled out Muslims specifically.
For many Muslims, it's a political moment that carries echoes from the early 2000s, when the 9/11 attacks and the Afghanistan and Iraq wars generated hostility toward Muslim communities in the United States, often accompanied by discrimination and racist violence.
“When members of Congress speak, it’s not just words,” said Iman Awad, the national director for policy and advocacy for the Muslim American advocacy group Emgage Action. “It shapes public perception. It legitimizes prejudice.”
Tennessee Rep. Andy Ogles in his social media post stated flatly that Muslims don't belong in the United States. He stood behind it after criticism mounted, later writing that “paperwork doesn’t magically make you American” and that “Muslims are unable to assimilate; they all have to go back.”
Asked about Ogles’ post on Tuesday, House Speaker Mike Johnson said he had spoken to members “about our tone and our message and what we say.” He said Ogles used “different language than I would use,” but added that he believes the issue raised by the comments is “serious.”
“There’s a lot of energy in the country, and a lot of popular sentiment that the demand to impose Sharia law in America is a serious problem," Johnson said. "That’s what animates this.”
Sharia is a religious framework that guides many Muslims’ moral and spiritual conduct. References to “Sharia law” have often been invoked by officials to suggest Muslims are attempting to impose religious practices on communities in the United States.
Many Republicans point to a Muslim-centered planned community near Dallas as proof of “Sharia law” — though the developers have denied the allegations and said they are being targeted because they are Muslim.
With Johnson not condemning Ogles’ remarks — or to recent comments from Florida Rep. Randy Fine that “the choice between dogs and Muslims is not a difficult one” — the anti-Muslim rhetoric grew louder. After the photo circulated of Mamdani at the iftar dinner, several Republicans responded with critical posts.
Democrats broadly condemned the GOP messages. Chuck Schumer, the leader of Senate Democrats, called Tuberville's post “mindless hate.”
“Islamophobic hate like this is fundamentally un-American and we must confront and overcome it whenever it rears its ugly head,” Schumer said.
Mamdani — in response to Tuberville's post that “the enemy is inside our gates" — said: "Let there be as much outrage from politicians in Washington when kids go hungry as there is when I break bread with New Yorkers.”
Federal officials identified a man who rammed his vehicle into a hallway at Temple Israel in West Bloomfield Township, Michigan, this week as a naturalized citizen born in Lebanon. Officials have said that the man had lost four family members in an Israeli airstrike in his native Lebanon last week, just after sunset as they were having their fast-breaking meal during the Muslim holy month of Ramadan
In Virginia, Mohamed Bailor Jalloh opened fire in a classroom at Old Dominion University before ROTC students subdued and killed him. Court documents showed that he had previously served time for attempting to aid the Islamic State and was released less than two years ago.
Some Republican lawmakers claimed vindication for their views. Others pushed for legislation. Minnesota Rep. Tom Emmer, the House GOP’s whip, said “the security of our nation hinges on our ability to denaturalize and deport terrorists.”
West Virginia Rep. Riley Moore said he would introduce a bill to denaturalize and deport any naturalized citizen who “commits an act of terrorism, plots to commit an act of terrorism, joins a terrorist organization or otherwise aids and abets terrorism against the American people.”
Similar rhetoric and policy pushes have surfaced before and drawn controversy. Last year, protesters connected to demonstrations over the Israel-Hamas war were arrested and targeted by authorities, including former Columbia University graduate student Mahmoud Khalil, a Palestinian activist the government has sought to detain and deport.
Middle East conflicts bringing domestic tensions is nothing new. With the war in Gaza, both Muslim and Jewish communities have faced faith-based discrimination and attacks.
Mamdani said the posts invoking the 9/11 attacks are problematic not just because of the words, but because of "the actions that often accompany them.”
“I think too of the smaller indignities, the indignities that many New Yorkers face, but that Muslims are expected to face in silence,” Mamdani said. “Of the exhaustion of having to explain yourself to those who are not interested in understanding. Of the men who introduce themselves by their given name only to be called Muhammad for years on end.”
The stark silence from Republican leaders, including President Donald Trump, reflects a broader change in the party. After the Sept. 11 attacks in 2001, Republican President George W. Bush visited the Islamic Center of Washington, D.C., to explicitly warn against Muslim discrimination.
“America counts millions of Muslims amongst our citizens, and Muslims make an incredibly valuable contribution to our country,” Bush said during the visit, adding: “They need to be treated with respect. In our anger and emotion, our fellow Americans must treat each other with respect.”
“Those who feel like they can intimidate our fellow citizens to take out their anger don’t represent the best of America, they represent the worst of humankind, and they should be ashamed of that kind of behavior,” Bush said.
New York City Mayor Zohran Mamdani speaks during a Rental Ripoff Hearing at Fordham University on Wednesday, March 11, 2026, in New York. (AP Photo/Andres Kudacki)
Police tape hangs outside the Temple Israel synagogue Friday, March 13, 2026, in West Bloomfield Township, Mich. (AP Photo/Paul Sancya)
FILE - Rep. Andy Ogles, R-Tenn., arrives for a meeting with Speaker of the House Mike Johnson, R-La., at the Capitol in Washington, Dec. 20, 2024. (AP Photo/J. Scott Applewhite, File)
FILE - The U.S. Capitol is seen at sunrise March 9, 2026, in Washington. (AP Photo/Jose Luis Magana, File)
