It was an immediate hit in the band's native UK, reaching #12 on the UK Singles Chart on 21 February, and did even better in Australia, hitting #8 to become Duran Duran's first Top 10 hit anywhere in the world.

The song later appeared on the band's eponymous debut album Duran Duran, released in June, 1981.

The song was also featured in the 2016 video game Watch Dogs 2.

"Planet Earth" begins with a mid-tempo synthesised sweep backed with sequenced electronic rhythm, but the real rhythm section of throbbing bass and crisp drums soon kick in. Muted guitar carries the up-and-down throbbing as the singer joins in.

The song was the first to explicitly acknowledge the fledgling New Romantic fashion movement, with the line "Like some New Romantic looking for the TV sound".

The original demo had an extra verse at the end, as can be heard in the Manchester Square Demo version, released in 2009:

"I came outside I saw the nightfall with the rain, Sheet lightning flashes in my brain, Whatever happened to the world we used to know? I've got you coming over fear now."

The music video for the song was directed by future film director Russell Mulcahy, who would go on to direct a dozen more for the group.

Fairly primitive by the band's later standards, the video features the band (dressed in frilly, floppy New Romantic fashions) playing the song on a white stage tricked out with special effects to look like a platform made of ice or crystal. Interspersed with the performance are shots of the band members alongside the four elements. The video focused closely on the band's faces. The instrumental middle section features friends of the band from the Rum Runner nightclub dancing in their outlandish outfits. In an apocalyptic science-fiction style, various world facts cross the screen as the video plays, including: "The area of the surface of the earth is 196,937,600 miles"; "247,860 people are born every day"; "The oldest known song is the Shadoof Chant"; and then it ends with a warning of "Doomsday." At the end of the video, singer Simon Le Bon leaps from the stage, caught in a freeze frame shot above an apparently bottomless abyss.

...
Wikipedia