Definition:Earth/Linguistic Note

Linguistic Note on Earth

Earth is a proper name: that of the planet on which (at time of writing) all humans live.

As such, its correct styling is for it to start with a capital letter.

This is the convention to be used on $\mathsf{Pr} \infty \mathsf{fWiki}$.

However, in much literature it can be seen referred to as the earth, which is a bit like, for example, referring to Albert Einstein as the albert.

In recent literature, particularly popular, new-age and poetic, there is a trend to referring to the place as Planet Earth.