Stranger from Venus

Stranger from Venus aka Immediate Disaster and The Venusian is a 1954 UK blackandwhite science fiction film produced by Burt Balaban, Gene Martel, and Roy Rich, directed by Burt Balaban, and starring Patricia Neal and Helmut Dantine.

A journalist, Charles Dixon Kenneth Edwards, tries to learn more about the mysterious Stranger. Dixon learns the alien is able to communicate in several languages, and that the mysterious stranger has learned quite a bit about humanity from listening to radio broadcasts and viewing television transmissions. The stranger also explains to the journalist how his spacecraft uses magnetic brilliance for propulsion, supplied by the other planets as they move in their orbits.When governmental officials come to visit the stranger, he confides in them the purpose of his visit to Earth. He is here to prepare the way for the arrival of another spacecraft carrying his superiors, who will be giving a dire warning to Earths leaders. Humans are developing very dangerous technologies without measuring their long term destructive consequences nuclear explosions create very dangerous magnetic fields. These technologies are a threat to Venus and the other planets in the solar system. Should fifty hydrogen bombs be exploded in the same general location during a future atomic war, it would have dire consequences, moving the Earth out of its orbit and affecting its gravity. This loss of Earths gravity would also affect the orbits and gravity of all the planets in the solar system. The stranger makes a promise that as soon as Earth eliminates these dangerous technologies, Venus will share its higher scientific knowledge with all of Earths researchers. ........

Source: Wikipedia