Musk: The Earth should be called a water balloon with a dream trip to Mars

Billionaire Elon Musk responded to a photo showing the Pacific Ocean on either side of Earth's equator. The photo, which shows vast blue oceans and few lands in corners, was shared on Twitter by an account called Engineering World.

Musk replied: "The earth should be called a water balloon. "About 71 percent of the Earth's surface is covered by water, and the small portion that remains is land. Most of this water is seawater, less than 3% of the water is fresh water, and almost all of it is frozen, locked in polar ice sheets, glaciers and other ice. The small amount of fresh water left is a usable source of water for all of our water uses.

The SpaceX founder often talks about his dream of building cities on Mars. SpaceX's original idea was to make life more planetary. He said that if Earth experiences a catastrophe, humans settling on other planets like Mars could protect civilization.

Musk's vision is to send humans to Mars by 2026, though several countries, including the Uae, China and the United States, are vying for the achievement.

Musk said back in 2016: "History will split in two directions." One way is that we stay on Earth forever, and then eventually there will be an extinction event. He also said that space colonies need large populations to be self-sufficient.