Denomination of 'earth'

[Anonymous]

Hello, teachers!

- Muslim scientists in the 14th century concluded that [the earth, the Earth, Earth] is round.
I think these are all grammatically OK, but in everyday expressions 'the earth' is preferred, and in scientific expressions 'the Earth' is dominant, but 'Earth' is not very common. Am I right?

Thank you very much.
Best Regards.

[Rusty]

- Muslim scientists in the 14th century concluded that [the earth, the Earth, Earth] is round.
I think these are all grammatically OK, but in everyday expressions 'the earth' is preferred, and in scientific expressions 'the Earth' is dominant, but 'Earth' is not very common. Am I right? (When referring to the planet, Earth is capitalized. Whether the article is used depends on the sentence.
Example: We live on Earth. The Earth rotates around its axis. Without capitalization, earth is a synonym for ground, soil, dirt. They removed tons of earth in order to lay the foundation. The earth that was removed was hauled to another location. All uses are common).