The theory also helped to explain the empirically observed regular pattern of increase in the diameters of the orbits of the planets of the Solar System, from inward to outward.

This result was a natural outcome of the increasing size of "planetary eddies" of gas and dust farther from the centre of the early solar system.

[5] Shortly after the end of the Second World War in Europe, the Russian émigré American physicist George Gamow co-authored an influential paper supporting Weizsäcker's work on planetary formation in the early solar system.

[7] During the Second World War, Weizsäcker joined the German nuclear weapons program, participating in efforts to construct an atomic bomb, while based at the Kaiser Wilhelm Institute in Berlin.

As early as August 1939, Albert Einstein warned U.S. President Franklin D. Roosevelt about this research and highlighted that "the son of the German Under-Secretary of State, von Weizsäcker, is attached to the Kaiser-Wilhelm-Institut in Berlin where some of the American work on uranium is now being repeated.

"[8] As a protégé of Werner Heisenberg, Weizsäcker was present at a crucial meeting at the Army Ordnance headquarters in Berlin on 17 September 1939, at which the German atomic weapons program was launched.

This latter view, largely based on postwar interviews with Heisenberg and Weizsäcker, was put forward by Robert Jungk in his 1957 book Brighter Than a Thousand Suns.

In a 1957 interview with the German weekly Der Spiegel, Weizsäcker frankly admitted to the scientific ambitions of those years "We wanted to know if chain reactions were possible.

Original sources about this question were not revealed until 1993, when transcripts of secretly recorded conversations among ten top German physicists, including Heisenberg and Weizsäcker, detained under Operation Epsilon at Farm Hall, near Cambridge in late 1945, were published.

"[13] But the "Farm Hall Transcripts" also revealed that Weizsäcker had taken the lead in arguing for an agreement among the scientists that they would claim that they had never wanted to develop a German nuclear weapon.

This story was untrue at least to the extent that the detainees also included scientists actively engaged in eager attempts to build a nuclear bomb, namely Kurt Diebner and Walther Gerlach.

"[16] Weizsäcker himself stated that Heisenberg, Karl Wirtz and he had a private agreement to study nuclear fission to the fullest possible extent in order to "decide" themselves how to proceed with its technical application.

Just as little, there was no passion to make the bomb..."[17] In a recent report based on additional documents from Russian archives, historian Mark Walker concludes that "in comparison with Diebner [and] Gerlach ... Heisenberg and finally Weizsäcker did obviously not use all power they commanded to provide the National Socialists with nuclear weapons".

[18] Ivan Supek (one of Heisenberg's students and friends) claimed[19] that Weizsäcker was the main figure behind the famous and controversial Heisenberg–Bohr meeting in Copenhagen in September 1941.

[26] Opinions are split on the question of whether he accepted his share of responsibility for the German scientific community's efforts to build a nuclear weapon for Nazi Germany.