I wasn't sure how to correctly spell “Earthling,” so I queried The Post's handy stylebook Slack channel. Personally, I'd cap Earthling and lowercase all other alien races just to show them who's boss. Question for @MerriamWebster from @WashingtonPost science desk: Why is earthling lowercase but Martian capitalized? @laurahelmuth — Merriam-Webster (@MerriamWebster) April 5, 2017The dictionary had spoken. And even if it lists “Earthling” as an acceptable variant, it would still be Post style to defer to the primary spelling listed.

Source: Washington Post April 05, 2017 19:52 UTC