The birth of the sea
The sea may have been formed by tremendous rains. Or, it may have been
formed by steam from inside the earth.
Scientists think the earth was formed more than four and one-half
billion years ago. There was no water on its surface for a long time.
Its inside was so hot that it was a liquid, as much of it still is
today. Its outside, too, was probably so frightfully hot that a drop of
water touching it would simply have sizzled at once into steam.
Slowly, the outside of the earth cooled off. Some scientists think that
when the earth cooled enough, water vapor in the atmosphere changed into
water and fell to earth as rain. Such a great rain would have lasted a
very long time. Gradually, all the low parts of the surface would have
filled up with water.
Other scientists think that as the earth’s surface cooled, steam came
rushing up out of volcanoes and geysers, just as it does today. When the
steam hit the cool air, it was changed into water. The water then ran
downhill. Slowly, over millions of years, it filled up the lowest parts
of earth’s rocky crust.
So, we don’t know exactly how the sea was formed. But from what
scientists have learned about the earth’s rocks and its chemistry, they
think the sea must have been formed in one of these two ways—or,
perhaps, in a combination of both ways.
