Learn English – Does “on earth” replace “on the earth” in modern English

definite-articlesidiomsmeaningprepositional-phrases

I am a non-native English speaker. Since school, I was taught "on the earth" is equal to "in the world", and "on earth"'s meaning should be "indeed". But nowadays, I find "on earth" has replaced "on the earth" in many articles. So I want to make sure is it right to use "on earth" to replace "on the earth"?

Best Answer

The word earth is commonly used to mean two things 1) soil, dirt, the substance that keep the trees upright and help you to grow beans and tomatoes, the material of the world; the ground, the world 2) the second meaning of earth is the planet Earth; a member of the Solar system of the planets; the third orb from the Sun. (that is called Astronomical sense)

When it is used in astronomical sense (2) it takes the definite article the and it is capitalized at the same time.

What on earth you are talking about? Means what you say is astonishing, or clarify your meaning, it is not easily understandable. Down to earth means humble, and approachable. come down to earth means be real, stop being high and mighty etc.

on the earth DOES NOT MEAN equal to;

on earth DOES NOT MEAN indeed

Not in American speech anyway.