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Is “Earth” Capitalized? When Should We Capitalize It?

Is “Earth” Capitalized? When Should We Capitalize It?

When should we capitalize the word “earth?” This question has puzzled many students and grammar enthusiasts for years. Some people argue that the word should always be capitalized, while others believe it should only be capitalized when referring to our planet. So, is earth capitalized, and which is correct?

The word “earth” is capitalized when used as part of a proper noun (it is about any specific object or place). For example, I live on this planet called Earth. Earth, in this case, is a specific planet. However, don’t capitalize the word when referring to the ground or soil.

We’ll explore the rules for capitalizing “earth” and provide some examples to boost your comprehension. We’ll also discuss when not to capitalize the word to clear the confusion. Let’s now take a look at the detailed arguments for both sides.

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Rules for Capitalizing “Earth”

The three common rules for capitalizing the word “earth” include: when used as a proper noun, referring to the planet you reside in, and in scientific publications.

These rules have to be adhered to; it makes your content relevant. Below is a detailed explanation with examples of the three rules of capitalizing “earth” we’ve just mentioned.

Earth as a Proper Noun

When “earth” acts as a proper noun, then it must be spelled with a capital letter: Earth. There are certain rules in English that state when proper nouns must be capitalized. For instance, when listing the names of specific planets, one must capitalize them.

That’s why “earth” is a proper noun and must be capitalized. But this does not apply to its occupants, “the people on earth.” You must also capitalize or spell out a proper noun at the beginning of a sentence. More on this later.

Example sentences:

  • The last of the Apollo missions was in 1972 and, for over a decade, it appeared that humans would never return to explore Earth’s neighbors again.
  • New reports show that Earth is changing, shifting its appearance with each new day.

Earth as a Planet and Place

Earth is a proper noun, and it is the name of our planet. “Earth” is always spelled with a capital letter when used as the name of a planet we live on. Do you know there’s also a place in Texas called “Earth?” Some people have also named some of their businesses and companies “Earth.” In such instances, make sure you capitalize the word.

Example sentences:

  • It feels good to live on Earth and enjoy everything the planet offers.
  • You should visit Earth, Texas, and experience current agricultural transformations.

When Talking About All the Planets

When you’re talking about other planets and referring to them as proper nouns, make sure you capitalize them. Also, do the same to “earth.” These planets include Mercury, Venus, Mars, Neptune, and Pluto.

Example sentences:

  • There is a big comparison in activities around Earth, Mars, and Neptune.
  • Mercury, Venus, and Earth are the first three planets in the solar system.

When Used in Scientific Publications

Also, when writing about the planet in a scientific context, it should be capitalized. “Earth” no matter how it appears in your scientific papers, capitalize it.

Example sentences:

  • Earth’s most shallow theory on the origin of planets and the solar system: A scientific analysis.
  • Is there an exact time an asteroid can spend from Earth’s equator? The truth about asteroid speed.

Exceptions for Capitalizing “Earth”

There are cases when “earth” does not have to be capitalized, but few. For instance, when referring to land, when used as a common noun, in non-technical contexts and when it’s used in idioms or adjectives.

Ready to learn more about these instances? Below are explanations and examples on each case when “earth” is not capitalized:

When Referring to Land

Whenever you refer to “earth” as soil or land, you don’t have to capitalize it. Don’t mistake this with using land as a proper noun. In this case, the word is not specific to anything. The same applies if you mean dirt, stratum, or surface.

Example sentences:

  • The contractors excavated the earth early today morning.
  • The earth around the ambassador offices is quite expensive.
  • Farming on this earth is the best thing you can do.

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When Used as a Common Noun

Do not capitalize “earth” if it appears as a common noun. Common nouns are nouns not specific to anything, any place, or anyone. Simply put, they are generic words.

Example sentences:

  • The smooth earth around the exit has caused a lot of injuries.
  • Every chemical engineer needs to know how metals are extracted from the earth.
  • The earth’s climate continues to change due to environmental activities.

When Used in Idioms or Adjectives

Idioms and idiomatic expressions with the word “earth” must always have the word in small letters. Note that these idioms’ meaning doesn’t necessarily have anything to do with the “earth.” All idioms have a symbolic meaning that you’re expected to deduce critically.

Example sentences:

  • What on earth is going on?
  • She was the most down-to-earth person you could ever meet.

In the sentences above, “what on earth” and “down to earth” are idioms. You’ll notice that their meaning is symbolic.

Some Edge Cases and More Alternative Rules When Capitalizing “Earth”

The two alternative rules when capitalizing earth is when it appears as the first word in a sentence and in titles.

When Earth Starts a Sentence

The word “earth” is always spelled with a capital letter when it starts a sentence, as an abbreviation, or an official name. There are many reasons why it’s always important to start a sentence with a capital letter.

Example sentences:

  • Earth is the third planet from the Sun and is also called Gaia, Terra, or Tellus.
  • Earth has been present since the creation of the Solar System 4.6 billion years ago.

When Earth Appears in a Title

Whether it’s a book, movie, or article title, capitalize “earth” to showcase its dominance. Normally, the first letter of every word in the title should be capitalized unless it is a preposition. But you can capitalize prepositions that are five or more letters long.

Articles should also be lowercased unless they are at the beginning of a sentence. The same applies to conjunctions.

Example sentences:

  • The “Earth Revolution Today” conference is scheduled to occur late this year.
  • The article on “Effects of Space Exploitation on Earth” was quite controversial.

10 Example Sentences with Correct Capitalization of “Earth”

Here are diverse sentence examples that cover different uses of “earth” when it’s capitalized or not. Read to have a comprehensive oversight on the word’s use in sentences.

  1. Do you know that Earth, Venus, and Mars are the only planets suspected to sustain life?
  2. If you love movies, I recommend watching “From Earth Without Love” when you have time.
  3. The explorers were the first humans to walk on earth’s surface.
  4. The forests of Earth are dwindling at an alarming rate.
  5. Earth is divided into seven continents: Asia, Africa, North America, South America, Antarctica, Europe, and Australia.
  6. Mary maneuvered all the four corners of the earth to win the competitive race.
  7. Thirteen billion years ahead, Earth coverage on the sea will reduce by half. Fact or fiction?
  8. Earth Water Ltd has the best water deals in town.
  9. As time passes by, Earth experiences different kinds of weather.
  10. Some other examples of the earth’s climates include: the tropical rainforest, tropical monsoon, Mediterranean climate and humid.


We believe that you now have the answer to “is earth capitalized?” As you can see, the answer to this question will depend on what you are writing. In general, we don’t capitalize earth when used as a common noun. However, if you are talking specifically about our homeworld as a proper noun, then yes-capitalize!