The Grammaring Guide to English Grammar with Exercises

The definite article with unique objects

The definite article is used before a noun which refers to a specific, unique object:

The moon

rises at 7.30 tomorrow.

The earth

revolves around the sun.

I'd love to live by

the sea

.

The captain checked the position of

the Northern Star

to determine the location of his ship.

Other examples are:

the sky

the equator

the North Pole

the Internet

the Matrix

the world

We should bear in mind, however, that there are other suns and moons in the universe, and when we refer to these they might not be considered as unique:

The planet Mars has two

moons

.

Every solar system has

a sun

.