10 Biggest Unsolved Mysteries About Planet Earth

Where did all the water come from?

Water, water everywhere. It covers 70 percent of Earth’s surface and earns it the nickname “the blue planet.” And yet… where did it come from? How is it so abundant on our planet when it’s almost nonexistent throughout the rest of our solar system? Most scientists believe that when planet Earth formed, about four and a half billion years ago, it was a dry, rocky planet. The most popular scientific theory states that the H₂O arrived in the form of several enormous asteroids filled with ice. Another suggests that the water actually has been around since Earth’s formation, and that the forming Earth retained it from the cloud of gas and dust that formed the solar system. However it happened, though, it’s certainly worked out well for Earth’s life forms. These are the most baffling unsolved mysteries about the universe.

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