Speculation about how he might apply his scientific energies ranges over a large area. His insights might be very useful to those who have struggled with limited success in the past three decades toward bringing the power of nuclear fusion from the laboratory to the industrial world. His knowledge, combined with his moral authority and sense of responsibility, might be a decisive factor in charting the future of nuclear energy in the West and around the world.
The diversity of his scientific interests has been astonishing. He' has made contributions in different and remote fields of science, both applied and theoretical.
It was his idea to use the solid compounds of deuterium and tritium with lithium rather than the liquid components that made the Soviet hydrogen bomb more effective, and a combat weapon. An equally major milestone was his proposal (made together with Nobel Prize winner Igor Tamm) to create a magnetic bottle to confine the high temperature plasma in thermonuclear reactors. Tokamaks operating today all over the world are based on that idea.
His most fundamental contribution, however, is related to the so-called violation of the time-reversal invariance discovered in 1964 by Fitch and Cronin (who shared the 1980 Nobel Prize m physics) in the decay of K-mesons. Sakharov was among the first to accept this very strange discovery as a physical reality and use it to explain a very fundamental cosmological puzzle: why the number of antiparticles in the universe is much smaller than the number of particles, although in the initial Big Bang their numbers were equal.
But it is always dangerous to speculate on what Sakharov will do. As one of his friends has noted, Sakharov has found solutions to problems in situations where the rest of us did not even know a problem existed.