CalTech astronomer Fritz Zwicky was the first to conceive of dark matter, supernovas and neutron stars. He also had a theory about colonizing the solar system using nuclear bombs. We could terraform other planets, he argued, by pulverizing them and then moving them closer or further from the sun.
If you've never heard of Zwicky, you're not alone. Virtually the entire public was unaware of his accomplishments, largely due to his abrasive personality and unique gift for alienating himself from the scientific establishment. "Astronomers are spherical bastards," he once said. "No matter how you look at them they are just bastards."
And, while many of his theories were proven right, Zwicky also advocated what could be charitably described as "eccentric" ideas—most notably, his proposals for using nuclear explosives to reconstruct the solar system.
Zwicky outlined his ideas in academic papers, newspaper interviews and magazine profiles that appeared sporadically between the 1940s and 1960s. (He died in 1974.) He was frustrated that his fellow scientists lacked the vision to take advantage of highly-advanced technologies that were just waiting to be built. "If many things in the past have gone wrong in the lives of men and in the lives of their communities it is because both small and large scale activities were blundered into without any thought or vision of universal planning," he wrote in a 1961 paper, which was published in the CalTech journal Engineering and Science. "Major actions by courageous and wise men will be necessary to avoid our continuing to blunder into the space age like unenlightened and selfish idiots."
So, yes, Zwicky tended to think big. He claimed to have designed the ultimate mining tool, the "terrajet," which he envisioned being employed to honeycomb the interior of the Earth with inhabitable, bombproof tunnels. But his really big ideas were reserved for other planets.
As explained in a 1961 profile that appeared in the Associated Press:
Mercury and Venus, now unbearably hot because they are too close to the Sun, can be shoved into orbits near the Earth by nuclear explosions, Zwicky said. Frozen planets like distant Jupiter can be blasted nearer the Sun.
"Jupiter is so big and its gravitational pull so strong that man would find it difficult to move about on the surface." Zwicky said. "The answer is to whittle it down to proper size with terrajets and nuclear power, using the debris to increase the size of Jupiter's moons so they too can be colonized."
Planets and moons with insufficient atmosphere could be provided with oxygen and water as byproducts of large-scale models of the terrajet earthborer, which could at the same time be digging channels for lakes and rivers.
Poisonous atmospheres could be dissipated by the same nuclear blasts that shove their planets into more favorable orbits. Studies now underway indicate nuclear bombs need not be highly radioactive, so the surfaces of the transported planets would not be permanently uninhabitable.
Another possibility that Zwicky outlined in his CalTech paper was turning our entire solar system into a spacecraft, by igniting nuclear fusion reactions in the sun:
In this connection it should be mentioned that it is a misnomer to talk about journeys within the solar system as belonging to the realm of astronautics. We should rather place them in the field of helionautics. Astronautics, strictly speaking, will be concerned with voyages to other stars. Remarkably enough, to achieve such feats, we might not even have to leave the earth. It would suffice to accelerate the sun itself to a very high speed and let it drag all its planets with it.
In order to exert the necessary thrust on the sun, nuclear fusion reactions could be ignited locally in the sun's material, causing the ejection of enormously high-speed jets. The necessary nuclear fusion can probably best be ignited through the use of ultrafast particles being shot at the sun. To date there are at least two promising prospects for producing particles of colloidal size with velocities of a thousand kilometers per second or more. Such particles, when impinging on solids, liquids, or dense gases, will generate temperatures of one hundred million degrees Kelvin or higher—quite sufficient to ignite nuclear fusion. The two possibilities for nuclear fusion ignition which I have in mind do not make use of any ideas related to plasmas, and to their constriction and acceleration in electric and magnetic fields.
Zwicky warned, repeatedly, that if the U.S. did not begin pursuing these projects, the Russians would beat us to it. Suffice to say, that didn't happen. But, based upon what I've read about the surreal astronomical theories that were making the rounds in Soviet science during that period, it would surprise me if someone hadn't considered it.
Zwicky photo via Fermilab