A curious boy who gazed at the stars from his mountainside Greek village and wondered how the universe came to be, Kosta Tsipis was only 11 when news arrived that the first atomic weapon had been dropped on Hiroshima, Japan.
“After the bomb went off, I sent away for a book because I wanted to understand it,” he told the Globe in 1987.
That moment set him on a course toward studying nuclear physics and becoming a prominent voice for disarmament during the Cold War arms race.
“I had come to believe that reason must prevail,” he said, and for him, that meant using his knowledge of the destructive capability of nuclear weapons to persuade politicians and ordinary people that a war of that magnitude was a dangerous folly.
Dr. Tsipis, who formerly directed the Program in Science and Technology at the Massachusetts Institute of Technology for International Security, died at home Saturday in Lasell Village in Newton after a period of declining health. He was 86 and had previously lived in Brookline for many years.
“So great are the excesses of the era of nuclear overkill that the American and Soviet strategic nuclear arsenals can be reduced by 50 percent — and more — without risking security,” he wrote in a 1988 op-ed for The New York Times. “Political, military, and psychological reasons strongly point toward the wisdom of reductions.”
Along with writing books and essays that appeared in publications such as the Times, the Globe, and Scientific American, Dr. Tsipis traveled to Washington, D.C., to lobby US senators, representatives, and officials of President Ronald Reagan’s administration.
During an era when that administration’s Strategic Defense Initiative — the “Star Wars” missile defense system — was much in the news, Dr. Tsipis published his book “Arsenal: Understanding Weapons in the Nuclear Age.”
He offered a “layman’s primer on America’s present and planned nuclear arsenal,” reviewer Sue Halpern wrote in the Times.
“Writing from a scientific, not a political, perspective and drawing on unclassified government documents,” Halpern added, “Mr. Tsipis addresses vital questions: How, theoretically, does the hardware work? What are its vulnerabilities? Will it work in practice? Does it enhance American security?”
And his research ranged beyond weapons to the havoc they would wreak.
Dr. Tsipis was the lead author for “Nuclear Crash,” an MIT study that was based partly on four years of computer simulations of the consequences of nuclear attacks.
The study found that a limited attack on the United States by only 1 percent of the nuclear arsenal of what was then the Soviet Union would set off a decades-long collapse of America’s economy and lead to mass starvation.
An attack aimed at energy production, transportation, and other key industries could leave survivors at “near-medieval levels of existence,” said the study, which was released in 1987.
“Ours is the first study to be quantitative on the minimum needed for so-called mutual assured destruction,” he told the Globe that year.
Dr. Tsipis “was very much in a tradition that had been established, especially at Harvard and MIT, of scientists — especially physicists — getting involved with issues regarding defense and disarmament,” said Fred Kaplan, who had been one of his students at MIT and later was the Globe’s defense reporter.
Those scientists were not simply lobbying for arms reductions, “but were applying their fields of science to actually researching the effects of these things and ways they can be controlled,” said Kaplan, an author who is now the national security columnist for the online site Slate. “They got deeply involved with public policy, and Kosta very solidly fell into that tradition.”
An only child, Kosta M. Tsipis was born in Athens on Feb. 12, 1934, and grew up in a small village near Delphi on Mount Parnassus. His parents were Michael Kosta Tsipis, an engineer, and Zoe Alexiou.
“His life is an amazing story,” said Dr. Tsipis’s son Yanni of Westwood.
During World War II, “his parents took in a Jewish family and sheltered them,” Yanni added. “If the Germans had discovered that, they all would have been executed.”
Sitting in his MIT office during the 1987 Globe interview, Dr. Tsipis said that the “war was existentially terrorizing. It completely defied rationality.”
At times, German soldiers conducted sweeps of the village, counting residents and mattresses to see if families were hiding anyone.
“I think that experience informed his whole life and forged a moral compass,” Yanni said.
After completing high school in Athens, Dr. Tsipis secured a spot at Rutgers University in New Jersey and traveled to the United States in 1954.
He married Magda Yannousi, whom he met on the ship on the way over. They had a son, Mikel of Framingham, and their marriage ended in divorce.
Dr. Tsipis graduated from Rutgers with a bachelor’s degree in electrical engineering in 1958 and a master’s in atomic physics in 1960. He received a doctorate in high energy nuclear physics from Columbia University in 1966 and began teaching at MIT.
While there he met Judith Ebel, a graduate student in another department, and they married in 1970. After finishing her doctorate in biology at MIT, she was a biology professor at Brandeis University, where her husband also taught for about a decade after his time at MIT.
“He was a wonderful loving husband,” she said.
They had two sons, including Andreas, who died in 1998 of Canavan disease, a fatal, progressive neurological disorder. The experience led Judith to found the Genetic Counseling Program at Brandeis in 1992.
“He inspired the founding of the most respected program in genetic counseling in the country that trains specialists to help people like his mother and his father,” Kosta Tsipis said in a eulogy at Andreas’s funeral.
Andreas “made the lives of many people richer and their understanding broader” and he “made his family stronger and wiser,” Dr. Tsipis added. “That’s quite a list of achievements for a young man who communicated mostly with his smile.”
In addition to his wife and two sons, Dr. Tsipis leaves four grandchildren.
A celebration of his life and work will be announced.
Though Dr. Tsipis was a renowned physicist, he also “had a Greekiness about him,” his wife said. “Even though he became an American citizen, he maintained that Greekiness verve of life that was very special.”
Dr. Tsipis, who was an informal adviser to George Papandreou, a former prime minister of Greece, was “a warm and passionate soul who loved life — people, food, a good tray of baklava — and always carried with him a concern for human beings that I think came from his experiences as a child,” Yanni said.
Kaplan recalled that Dr. Tsipis “was very keen on the central experiences of life in a way that you wouldn’t always expect from someone coming out of this field. He understood that the whole point of this is to build a life that is more creative and enriching.”
Speaking Greek, English, French, and some Italian, Dr. Tsipis “was an amazing life force,” his wife said.
Over the door of their second home in Truro was a sign they had made with the Latin phrase hic habitat felicitas — here lives happiness.
Bryan Marquard can be reached at email@example.com.