Professor Astro Cat's Deep-Sea Voyage

Professor Astro Cat's Deep-Sea Voyage — page 7
forming oceans We might be standing on solid ground but did you know that our planet has more water than land In fact over 70 percent of our Earth is covered by ocean Not only is the ocean huge but it’s also very old To see where all this water came from we need to go back in time about 4 6 billion years to when Earth was just starting to form out of clouds of dust swirling around the sun COOLING DOWN As Earth formed it became very hot causing the water within it to erupt as water vapor from volcanoes then condense or fall as rain covering the whole planet Some water also probably came from icy comets colliding with the early Earth A HOT ROCK Earth was created when rocks dust and metal collided Within all these materials were minerals that contained water FROM WATER TO LAND About 375 million years ago as the ocean teemed with a huge variety of life some animals that lived close to land evolved to breathe air and moved to live on the land permanently Some then decided to move back to the ocean In fact whales and dolphins evolved from a land mammal EARTH 4 6 BILLION YEARS AGO LIFE IN THE OCEAN Some scientists believe that around four billion years ago the very first life on Earth began somewhere in the ocean deep down near hydrothermal vents Over the next few billion years this tiny and simple microscopic life got more complicated as it developed 12