Warning From Space (1957)

Overview

How's your astronomy? Planet Paira, as you know, occupies the same orbit on the same elliptical plane as Earth, but on the opposite side of the sun, which makes it impossible to see from Earth, so don't try to find it with your telescope. I did, and look at what happened. When an envoy of starfish-like aliens arrive from said planet to warn mankind about a runaway planetoid that is on a collision course with Earth, fearing that their own planet will be destroyed as well, it's up to humble Japanese scientists to attempt to prove that nuclear bombs are good for us.