He studied Theoretical Physics in Hamburg, centered on general relativity, and got his diploma in 1956 and his PhD in 1959, advised by Pascual Jordan.

Besides Jordan and Ehlers, he had scientific contacts with (in historical order): Klaus Hasselmann, Wolfgang Pauli, Roger Penrose, Peter Bergmann, Thomas Gold, John A. Wheeler, Felix Pirani, Brandon Carter, Hermann Bondi, Rolf Hagedorn, Nigel Holloway, Nino Zichichi, Peter Scheuer, Richard Feynman, Malvin Ruderman, Philip Morrison, David Layzer, Zdenek Kopal, John Maddox and Paul Dirac.

In 1984, Zichichi asked him to direct yearly courses at Erice,[3][4] on neutron stars, active galactic nuclei and astrophysical jets.

His scientific interests thereby moved from gravitational waves (of general relativity) to neutron stars black holes and accretion disks, to the astrophysical jets, to supernova explosions and gamma-ray bursts, further to terrestrial plate tectonics, to the Tunguska event (1908), and to the osmotically pumped water circulation in plants.

A new explanation has been given by Kundt in his 1999 analysis of the Tunguska event based on the facts collected by Moscow's Andrei Olchowatow, as the present-day formation of a kimberlite, in which ten megatons of methane were explosively ejected, whose icy remnants in the upper atmosphere caused three bright nights to follow in Europe.