Humans in the Universe
13 Billion – 200,000 Years Ago
Scientists offer a different explanation, based on evidence gathered from sources on
earth and in space. Here’s what they might say:
Long ago, there was no time...There was no space...But 13 billion years ago...things
Where there had been nothing, now there was everything. The whole universe – tiny,
and fantastically hot. For an instant, it expanded faster than the speed of light. Then it
slowed down but kept expanding, as it still is. As the universe cooled down, clouds of
hydrogen and helium gas began to gather together, their centers getting hotter and
And when they were hot enough, the hydrogen atoms began to fuse together with the
power of millions of hydrogen bombs.
They clustered together in vast galaxies, each containing billions of these new stars.
Four and a half billion years ago – when the universe was already two-thirds as old as it
is today – a star was born near the edge of a galaxy we call the Milky Way: OUR SUN!
Around the sun, wisps of matter were drawn together by the forces of gravity to create
the planets of our solar system…
…Including the third rock from the sun: OUR EARTH!
The early earth was incredibly HOT. Heavier metals melted and sank to the center,
lighter metals rose to the surface, and gases bubbled up to make the earth’s first
atmosphere. By four billion years ago, the earth had cooled enough for water to
condense into oceans. And so the earth turned blue. The surface hardened into thin
“plates” floating on the molten materials underneath. Those “plates” float on the surface
to this day, constantly changing the landscapes and weather patterns on the earth’s
Where the plates collided, great mountains were formed and where they tore apart,
melted rock poured out from under the surface. Deep within the newly formed oceans,
complex chemicals were created using volcanic heat for energy. Some of these
chemicals became so highly organized that they formed cells – the first LIFE ON
Living organisms changed the atmosphere, adding oxygen. Cells developed that could
“breathe” oxygen and, about 600 million years ago, the first multi-cellular organisms
arose in the earth’s oceans.
The first animals appeared not too long after! After a while, some animals moved out of
the oceans and onto the land. Dinosaurs were the most successful of the early land
animals but about 65 million years ago, a giant meteor came crashing down to earth
and the dinosaurs were no more! This left a new class of animals dominant on the land.
Over time, a particular group of mammals emerged that lived in trees. To survive in that
environment, these mammals needed 3D vision and large brains to process visual
information. They also needed hands that could grip with precision. (Imagine living in a
tree without any of these. You’d fall out!) These mammals were the first PRIMATES.
Then, about 7 million years ago in Africa, a branch of those primates became the first to
stand upright.
These were the first HOMINIDS. Different hominids lived on earth over the next 7 million
years, some at the same time as others, but only one survives to this day...US!!!
The earliest hominids lived in small, family-sized groups. They gathered plants, insects,
and small animals, and they occasionally scavenged the meat of larger animals killed by
predators. The first hominids had brains about the size of a modern chimp’s. Over time,
new species developed ever-larger brains, and they began to make more and more
complex tools. The Australopithecines likely used sharp sticks to dig for food while
Homo habilis hominids, a later species, were able to make stone tools. They chipped
‘flakes’ of stone from large rocks and used those flakes as knives. They also used the
leftover ‘core’ to scrape out hides and do other jobs.
Homo erectus hominids, which lived on Earth for almost two million years, were
probably the first ones who could control and use fire. They were also the first to leave
Africa. Their fossils have been found as far away as China and Java (in modern
Social relationships among our ancestors were complex. Like modern chimpanzees,
early hominids must have been quite clever, with a great deal of social cooperation and
group politics. They cared for each other, especially their children.
Well, in some ways that’s true – but this species was different in many other respects
from our species. We have no evidence, for example, that they had art, religion, or

Humans in the Universe notes