Revolutionary ideas require great concentration to form and particular care to spread.

Those skills helped physics pioneer Niels Bohr redefine how we look at the world.

His Nobel Prize-winning theories helped people understand quantum mechanics and atomic structure.

Those concepts leapt from his unbreakable concentration. When pondering a complex problem, his limbs would go slack and his face would take on a blank expression.

During construction of what would become the Niels Bohr Institute in Copenhagen, Denmark, in 1921, Bohr said he never noticed workmen hammering outside his office because "noise that is not directed at me I do not hear at all."

He was forever relighting a pipe that would go out while his mind focused on some of the knottiest hunches in science.

Bohr (1885-1962) was far from absent-minded. His thought process was structured and thorough.

With a new idea, Bohr would pick a theme and explore it from start to finish, working concepts until he was satisfied.

In the early 1900s, quantum physics was a young field. Theories were outpacing experimentation and reliable data. Evidence was vague, since viewing the atom wasn't possible. Approaching data from a proper prospective, Bohr knew, was the key to understanding.

He also knew that finding answers meant keeping an open mind.

He turned to the best thinkers in the scientific community to push his work ahead. He cultivated productive relationships that would often last for years.

Landing Help

Early in his career, Bohr sought mentors who would encourage him. His work with Ernest Rutherford, who discovered the nucleus, was among the most influential.

"Niels Bohr's openness, his surprising humor, his strong charisma and his propulsive ideas and conversation often created close and lasting friendships," said Niels Blaedel, author of "Harmony and Unity: The Life of Niels Bohr."

The Bohr-Rutherford teamwork produced the Bohr model. It posits that electrons maintain discrete orbits around the nucleus of atoms and emit energy when jumping from orbit to orbit.

Bohr's idea become a bedrock of quantum theory and won him the 1922 Nobel Prize in physics for, said the Nobel foundation, "his services in the investigation of the structure of atoms and of the radiation emanating from them."

Bohr's energy was contagious.

He would stand at a blackboard filling blank spaces with a flurry of complex formulas and theories.

When he ran out of room, he'd use both hands and arms to wipe away the old ideas to keep his new ones flowing — a productive, if messy, arrangement. He kept chalkboards close at hand; if ideas struck him when he wasn't at the office, he'd simply start writing and invite his colleagues to his home.

Later, he turned to younger scientists for fresh ideas, assuming a role as father figure and teacher.

Bohr's belief in a vibrant community resulted in the 1921 founding of the Institute for Theoretical Physics at Copenhagen University.

In Bohr's words, it was a refuge where "new blood and new ideas are brought to the work through the young people's own efforts."

It embodied the camaraderie and support for new ideas that Bohr considered vital.

Finn Aaserud, the director of the Niels Bohr archive, says Bohr instilled it with the "Copenhagen spirit" — intellectual independence amid an informal social setting. At the institute, scientists would lie on tables and watch American Western movies. Discussions were Socratic and freewheeling.

The result? The institute produced some of the foundations of modern quantum mechanics and established the "Copenhagen interpretation," which sparked a revolutionary debate over the role of the observer in physics.

When the Nazis grabbed Denmark in 1940, Bohr tried to maintain the institute's work and spirit, never hiding his anti-Nazi sentiment or Jewish lineage.

He prized intimate talks with his peers. Freeman Dyson, in his book "Disturbing the Universe," noted, "All his life he had been walking and talking, usually with a single listener who could concentrate his full attention on Bohr's convoluted sentences and indistinct voice."

Bohr also prized contention. He and Albert Einstein famously disagreed over issues still hotly debated in the physics world today.

Bohr held the position that atomic particles are unobservable because the act of measuring particles distorts their behavior. Einstein held the more classical position that they could be observed.

Bohr was always quick to point to their discussions as a great resource for the evolution of his own ideas.

"He utters his opinions like one perpetually groping and never like one who believes he is in possession of definite truth," Einstein said of Bohr.

Bohr appreciated that the accomplishments of even the brightest scientific minds would lead only to fascinating questions.

"(He) would never regard achieved results in any other light than as starting points for further exploration," said Belgian physicist Leon Rosenfeld in "Niels Bohr: His Life and Work As Seen by His Friends and Colleagues."

Bohr agreed, and said of quantum physics, "If it does not boggle your mind, you understand nothing."

Bohr was the first to predict that his discoveries would be improved upon or contradicted as knowledge grew. His most influential theories were amalgams of fact, intuition and unprecedented theory.

He expected his theories to change, and sought out others to debate and sharpen his concepts.

Bohr's love of science and discussion were nourished almost from birth.

Born in Copenhagen, he was surrounded by great scientific minds at an early age.

His father, Christian, was a physiology professor at Copenhagen University and was nominated for a Nobel Prize in 1907 and again in 1908 for his work on the effect of carbon dioxide in human blood. The dinner table was a place of lively and informed discussion.

His brother Harald, a distinguished mathematician, helped him talk through many of his ideas.

Bohr's own wife and children were central to his life as well.

He married Margrethe Norlund in 1912. He used her as an invaluable sounding board for his ideas, just as he did other physicists. Bohr would write affectionately of time spent on trips to the country with his wife as occasions where "we" would finish writing a paper.

The joy Bohr took in his six sons was equally immense. That didn't last long. Two died young — one in a boating accident, the other from an illness, likely meningitis. Their deaths crushed Bohr, but he passed on his passion for scientific achievement. Bohr's son, Aage Niels, would further his father's legacy by winning the Nobel Prize in physics in 1975 for his work on the theory of the structure of the atomic nucleus.

Niels Bohr balanced work with diversion. He enjoyed crossword puzzles, biked, hiked and maintained a passion for soccer — he tended goal — for much of his life.

He also worried over the political nature of his work, specifically the impact of atomic science and its role in shaping national destinies.

Tough Talent

Bohr's talent made him a target of the Nazis and later the Soviets, who plotted to kidnap him after his 1943 escape from occupied Denmark.

He eventually reached America and began work on the Manhattan Project. There, he considered the implications of his work.

In 1944, he tried to persuade President Franklin Roosevelt and British Prime Minister Winston Churchill to share the existence of the nuclear bomb with the Soviets in order to head off the coming postwar arms race. He was branded a security risk for his efforts.

In 1950, Bohr wrote the United Nations about "the ideal of an open world, with common knowledge about social conditions and technical enterprises, including military preparations, in every country."

BY KIRK SHINKLE