solution.md

The variable for our planet

That's simple:

let ourPlanetName = "Earth";

Note, we could use a shorter name planet, but it might not be obvious what planet it refers to. It's nice to be more verbose. At least until the variable isNotTooLong.

The name of the current visitor

let currentUserName = "John";

Again, we could shorten that to userName if we know for sure that the user is current.

Modern editors and autocomplete make long variable names easy to write. Don't save on them. A name with 3 words in it is fine.

And if your editor does not have proper autocompletion, get a new one.