This was the second of George Pal’s sf classics of the 1950s, made on the tail of the success of Destination Moon (1950). It was as big a success as Destination Moon had been and, like Destination Moon, went on to win that year’s Academy Award for Special Effects. It has all the same high points and all the faults of all Pal’s productions - an emphasis on effects and wondrous spectacle but with a rather mawkish and wooden human element, as well as the same political naivete and religious underpinnings of any Pal production. But also, sitting among the horde of B-budget sf films of the 1950s, it is an undeniable classic.

What Pal and the directors who worked for him had, and in none of Pal’s films more so than here, was an eye for spectacle. The shots of the rocket towering above the camera as it is being built on the mountainside, of the camera panning along a bookshelf taking in the collected literary works of the human race as they are photocopied - all of it is constructed with a feel for the momentous. And of course the film’s images of mass devastation - waves crashing through the streets of New York, ships floating on their sides between skyscrapers - have an incredibly potent resonance. Stills from both these scenes have been reproduced an enormous number of times in books and the images have an ability to speak all on their own without people having seen the film. (What is perhaps surprising - one supposes in seeing this after countless Irwin Allen-styled disaster epics - is the sparingness with which actual disaster scenes are shown. And most surprisingly of all is that the titular collision of worlds takes place entirely off-screen).

Throughout the 1960s George Pal attempted to mount a sequel to When Worlds Collide, which would have been adapted directly from After Worlds Collide (1934), the sequel that the original book’s author’s Balmer and Wylie wrote. However in the 1960s Pal’s importance as a producer began to wane and the project never got off the ground.

Pilot Dave Randall is given the job of transporting a parcel of astronomical observations from Mount McKenna Observatory in South Africa to the US. Journalists are desperate to find the contents of the parcel, even offering him bribes. Afterwards he discovers that the parcel contains calculations that prove a wandering star Bellus and its orbiting planet Zyra are on a collision course with the Earth. But when Dr Hendron announces his findings before the UN he is denounced. However a private group of financiers come to him offering to finance the building of a space ark so that a selected few can relocate on Zyra after the destruction of the Earth. As the astral bodies near they cause mass tidal waves as Hendron's team race to complete construction on the ark. Hendron then announces a lottery to select those to go aboard.