Alone among known planets, Earth has vast oceans on its surface and its landmasses are marked with lakes and extensive river ...

Earth and the other inner planets clumped together from the dry rock and dense metal that remained. Something must have happened, some millions of years later, to nourish those planets with water.

Chemical clues in zircon crystals suggest the rock in which they formed came into contact with fresh water 4 billion years ago, when Earth was thought to be covered in ocean.

"Venus has 100,000 times less water than the Earth, even though it's basically the same size and mass." The HCO+ molecule would form in the atmosphere, but individual ions wouldn't last long ...

NASA shared striking views of nearly all of Earth's water in new maps of the planet's global sea levels. When you purchase through links on our site, we may earn an affiliate commission. Here’s ...

Thus, fresh water had to be present on Earth before 4 billion years ago. Whether life also began so early in Earth’s history is a question we can’t quite be sure of yet.