1955 was a great time for sci-fi movies. World War II was well behind us, we had nuclear weapons, we were working on space travel, and anything was possible. The next threat to the world would have to come from outer space. This Island Earth put forth a likely scenario, at least for 1955 tech.
Starring Jeff Morrow (1907 - 1993), Faith Domergue (1924 - 1999) and Rex Reason (b. 1928), all as scientists, but Morrow was actually an alien. The notion that the invaders would send a complex machine called an interociter to a group of scientists to see if they could complete the task of building it and getting it to work, then use it to invade the Earth, was pretty scary back then.
The aliens were from Metaluna, which literally means "beyond the moon" and their planet is in trouble. They appear to be asking for our help after choosing the best and brightest scientists with their test, but they really want to bump us off and take our home. Rex and Faith showed them!
There were some others in this film who did well in their acting careers. Richard Deacon (1921 - 1984) appears as a pilot, and later shows up on "The Dick Van Dyke Show." Russell Johnson (b. 1924), who ends up on "Gilligan's Island" as the professor is also seen.
Most of the cast are relatively unknown today, but made many movies and TV appearances. Robert Nichols (b. 1924) has 111 titles on IMDb. He played Joe Wilson, who I believe was Rex Reason's assistant in building the interociter, if memory serves. Nichols appears in The Thing from Another World (1951) which is popularly known simply as The Thing and also cast James Arness (b. 1923) in the title role. He was in Monkey Business (1952) and Gentlemen Prefer Blonds (1953) with Marilyn Monroe, and a lot of great movies with great stars like Humphrey Bogart, Mickey Rooney and Bob Hope.
Lance Fuller (1928 - 2001) has 53 titles, Douglas Spencer (1910 - 1960) has 84 titles, Jack Byron (1885 - 1991) has 71 titles going back to silent films with This Island Earth being his last, and the list goes on.
We can forgive all the scientific mistakes they made because it was 1955. This movie is fun, but a little long. It goes well when you just want to kick back in the recliner and relax, or perhaps with some friends who have always wanted their own interociter. I have friends like that!