Today, about 3.5 percent of ocean water is salt. When planet Earth was still young, its atmosphere contained a mix of hydrogen chloride, hydrogen bromide, and other gasses from volcanoes. Oceanographers (scientists who study the ocean) believe that some of these gases dissolved in the early ocean, making it salty. Today, however, most of the salt in the oceans comes from rain. Rain falling on the land dissolves the salts in eroding rocks, and these salts are carried down the rivers and out to sea. The salts accumulate in the ocean as water evaporates to form clouds. The oceans are getting saltier every day, but the rate of increase is so slow that it hard to measure. If the oceans suddenly dried up, there would be enough salt to build a 180-mile- (290-kilometer) tall wall around the equator.
- How much of Earth is covered with land and water?
- Where is the deepest hole?
- How are caves formed?
- Is there life on planets in other solar systems?
- Which planet might float on water?
- Which planets have rings?
- Is a day the same on all planets?
- Who named our planets?
- What is Planet X?
- Which planets are called the gas giants?
- Why isn’t Pluto a planet anymore?
- Which planets are the rocky planets?
- How many planets are there?
- What is a planet?
- What is an orbit?
- How old is the solar system?
- What is the solar system?
- Why is the Andromeda galaxy so special?
- Which galaxy is closest to ours?
- What is outer space?
