Geology
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Earth Sciences

How was the Earth formed?

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2016-10-14 03:38:17

The Earth and all the planets are formed 4.5 billion years ago

with interstellar hydrogen gas and heavier elements previously

formed in earlier stars that had exploded.


The Sun, a young star, consists almost entirely of hydrogen and

helium, which are being converted into other elements by a process

of fusion, which generates the energy radiated by the Sun. However,

the Sun produces insignificant amounts of elements heavier than

carbon, since this fusion requires much higher temperatures. Some

stars do create heavier elements, and as they reach the end of

their lifespans, they explode as supernovas, releasing these

elements (and creating still more, notably the radioactive

ones).


Sometime more than five billion years ago, supernovae had exploded

in our neighborhood of the Milky Way galaxy, creating and spewing

out vast volumes of heavy elements. A tiny percentage of this

material (but still a huge amount by earthly standards) was

captured in the disk of gas that would form our Sun. Scientists are

beginning to discover planets around other nearby stars, indicating

that terrestrial planets (formed of heavy elements) also exist

around other stars.


Around 4.5 billion years ago, this gas coalesced into a small

number of balls, one of which was the Earth. These balls, or

planets, were very hot but cooled, forming an outer crust on the

smaller ones. The Earth could have continued to cool until it

solidified. However, with radioactive uranium as one of the

heaviest elements, the Earth's core can maintain an extremely high

core temperature almost indefinitely. The discovery of near-surface

geothermal "hot rocks" provides an example of the same

process.


The Earth's surface has not always had the same form or with the

same continents as it has now. A process of plate tectonics has the

continents drifting (at an incredibly slow but measurable pace)

across the surface. They split apart and ram back together to form

new land masses. The Himalayan mountains were formed when the

Indian land mass pushed into the southern boundary of the ancient

Asian land mass, folding the crust and forming mountains. Other

mountains were formed by similar processes.


The Earth's crust was originally formed from igneous rocks, much

like the rocks formed when lava cools. These rocks gradually

weathered away into sand and silt, which were deposited in the

valleys and on the ocean bed. Here, they were compressed into

sedimentary rocks such as sandstone and shale. The earth's surface

is constantly changing, and many sedimentary rocks were later

uplifted to form new mountains.

"Answer" id="Answer">Answer

It was made by something special, God. The King James Bible says in

Genesis 1:1 that "In the beginning God created the Heavens and the

Earth."


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