Enjoying EarthSky? Subscribe.

116,740 subscribers and counting ...

By in
| Earth on Jun 03, 2013

If you made a sphere of all Earth’s water, how big would it be?

Earth is the water planet. What if you could take all of the water on Earth and form it into a sphere? How big would it be?

We think of Earth as the water planet. But what if you could take all of the water on Earth and form it into a sphere, or bubble? How big would the bubble be? The U.S. Geological Survey (USGS) has the answer. All the water on Earth would fit into a sphere 860 miles (1,385 km) wide. That’s a lot smaller than Earth itself, as the drawing below shows.

All the water on Earth would fit into a sphere 860 miles (1,385 km) wide. Image via Jack Cook/WHOI/USGS

Surprised? Water planet, you said? In fact, there’s a lot of water in the large blue sphere depicted above. The largest sphere – representing all water on, in, and above Earth – would be about be about 860 miles (about 1,385 kilometers) in diameter. That’s in contrast to about 8,000 miles (about 12.5 thousand kilometers) for Earth.

Medium-sized sphere = Earth's liquid fresh water in groundwater, swamp water, rivers, and lakes. Smallest sphere = fresh water in all the lakes and rivers on the planet. Image via Jack Cook/WHOI/USGS

Or to put it another way, the largest blue sphere above holds 332,500,000 cubic miles (or 1,386,000,000 cubic kilometers (km3) water. We writers are always looking for analogies, but the best one I can think of to describe this amount is … well, it’s about as much as all the water on Earth.

See the smaller sphere over Kentucky? It represents Earth’s liquid fresh water in groundwater, swamp water, rivers, and lakes.

And do you see the even smaller (very tiny) bubble over Atlanta, Georgia? That one represents fresh water in all the lakes and rivers on the planet. USGS says that most of the water people and other earthly life require every day comes from these surface-water sources.

Bottom line: USGS says that all the water on Earth would fit into a sphere 860 miles (1,385 km) wide.

Read more about this story from USGS