1) The Earth formed from a cloud of gas and dust around 4.6 billion years ago as the solar system was taking shape. 2) As the young Earth cooled, heavier elements sank to form its core and lighter gases escaped to form an atmosphere. Water rained down to form the oceans around 4 billion years ago. 3) The first single-celled life forms developed around 3.6 billion years ago, protected by the oceans from intense solar radiation. Multicellular life emerged later and began moving onto land about 500 million years ago.

1. „„Life on Earth‟‟
By: Jerry B. Padilla Jr.

2. “How was the Earth created?”
The Earth, as well as the other planets and the Sun
were once nothing more than a large, slowly rotating ball of
gas and dust. This primal cloud began to contract because
of the elements (Hydrogen, Helium, Iron, Carbon, etc.)
were attracted to each other. The cloud rotated faster and
faster. It flattened out into a disk, and gave birth to the Sun.
The planets were formed from the outer parts of the disk.
Larger and larger concentrations of matter began to clump
together. This is how the planets were formed.

4. "How did life on Earth began?”
At first, the Earth was porbably nothing more than a
ball of molten rock and metal. The high temperature came
from the huge amounts of highly radioactive metals is still
contained. These metals released tremendous energy.
Heavier elements (Nickel and Iron) sank into the molten
Earth and formed its core. The mantel formed around the
core and the crust on the outside. Hot gases escaped from
thousands of volcanoes and formed its first atmosphere,
which contained substances like methane
and water vapor. Then water rained down in
violent cloudbursts, and formed the first
ocean.

5. "How did life on Earth began?”

7. “Did you know?”
The Earth‟s Iron Core, its high level of silicon, and its
oxygen-riched atmosphere are a very unusual combination
in the universe.
It was made possible by events in our solar system‟s
infancy. As the solar system developed, the Sun‟s intense
rays blew much of the Hydrogen outward. This left high
concentrations of heavy elements nearer the center –
where the Earth is.
Further out large hydrogen gathered around
small, dense concentrations of matter,
forming planets like Jupiter and Saturn.

8. “How did life on Earth began?”
In this primal atmosphere, the rays of the Sun
interacted with the elements to form large molecules. The
first single-celled life forms probably developed from these
molecules about 3.6 billion years ago. They were protected
from the Sun‟s intense radiation by the primal oceans they
lived in. And so life began on Earth.
Later, multicellular life-forms also
developed, and about 500 million years ago
they began to move onto land. In the
meantime, a new layer had formed in the
atmosphere – the Ozone Layer – and it
protected life-forms on land from dangerous
radiation.

10. “Curious Question?”
“Did life come to Earth from outer space?”
Some theorist claim that life was brought to
Earth from some other parts of the universe. The
basic materials from which life on Earth then
developed were supposed to be a tiny, single
celled life forms brought to our planet in fragments
of comets or meteorites.

11. “How did life on Earth began?”
An amazing variety of creatures evolved in
these 500 million years. Again and again,
however, enormous collisions – with planetoids,
for example – led to the extermination of up to
80% of these life-forms. The most famous os
these catastrophes led to the extinction of the
dinosaurs about 65 million years ago.

13. The history of humankind is very short
compared to the history of the Earth.