Illustration Credit & Copyright: Jack Cook, Adam Nieman, Woods Hole Oceanographic Institution, Howard Perlman, USGS

Explanation: How much of planet Earth is made of water? Very little, actually. Although oceans of water cover about 70 percent of Earth’s surface, these oceans are shallow compared to the Earth’s radius.

Spheres showing:
(1) All water-Largest sphere 1,384 km (860 mi) diam.
(2) Freshwater in ground, lakes, swamps, rivers– Medium sphere, 273 km (169.5 mi) diam.
(3) Freshwater lakes and rivers -Tiny sphere, 56.2 km (34.9 mi)

• In the first bar, notice how only 2.5% of Earth’s water is freshwater – the amount needed for life to survive.
• The middle bar shows the breakdown of freshwater. Almost all of it is locked up in ice and in the ground. Only a little more than 1.2% of all freshwater is surface water, which serves most of life’s needs.
• The right bar shows the breakdown of surface freshwater. Most of this water is locked up in ice, and another 20.9% is found in lakes. Rivers make up 0.49% of surface freshwater. Although rivers account for only a small amount of freshwater, this is where humans get a large portion of their water from.

Source: Astronomy Picture of the Day, USGS Where is Earth’s Water?

Here’s some more signs of life on this nearly infinitesimally small bit of our Universe: