Can Venus be transformed into an earth-like planet?

One of the most difficult cases of transforming other planets in the solar system into an earth-like world is that of Venus. There, the length of the solar day must be decreased by a factor of 100, the atmospheric pressure reduced by a factor of 90 and the atmospheric composition must be changed. A possible plan of action is described which involves the collisions of large asteroids with Venus to begin the desired transformations. The energy requirements of this 'thought experiment' show that any realistic attempts to terraform Venus can be undertaken only by societies which are capable of an extensive program of interstellar exploration.