Earth is known as a water planet because water covers approximately 71% of its surface. This is a significantly larger proportion than any other planet in our solar system.

Here's why this is significant:

* Abundance: The sheer amount of water on Earth is staggering. It's estimated that there are over 332.5 million cubic miles of water on Earth, with only about 2.5% of it being freshwater.

* Life-Supporting: Water is essential for life as we know it. All living organisms require water to survive and thrive. This vast amount of water has played a crucial role in the evolution and development of life on Earth.

* Unique Feature: The abundance of liquid water on Earth's surface makes it a unique planet in our solar system. Most other planets either have very little water or water that exists only in frozen or vapor forms.

While the vast majority of Earth's water is saltwater in oceans, the presence of such a large amount of water has had a profound impact on our planet's climate, geology, and the evolution of life.