关于英语翻译的一个小问题？

Question

维持地球生态整体平衡 maintain the overall balance of Earth's ecology为什么Earth前面不加the？

Answer 1

2. The Definite Article

2.1 The definite article is ´the´ and is used for specific or unique items:

the sky the English book the man in the white hat

2.2 It is also used before:
a) superlatives: Mount Everest is the highest mountain in the world.
b) the names of seas, rivers, mountain ranges (not individual ones):
The River Nile is in Egypt.
c) the plural names of countries:
Many people like the United States.

2.3 The definite article is NOT used before
a) the names of towns, countries and proper names (i.e. the names of people):London, Argentina, Mr. Jones
b) the names of meals:
Breakfast, lunch, dinner, etc.

2.4 The definite article is omitted before the following when these places are visited or used for their primary purpose:

Home, church, market, school, hospital, court, prison, work, sea, bed,
I go to church every Sunday. (to attend Mass)
He goes to work by bus.

When these places are visited or used for other than their primary purpose, the definite article IS used:

I´m going to the hospital to visit a friend.

Answer 2

maintain the overall balance of the earth's ecology.
不应该有加the吗？因为地球是特指？如果只有earth不是地表的意思吗？

Answer 3

地球只有一个，他是特指。