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June
22 , 2004 — When
did the universe begin? When will it end? Take a look below
at our basic timeline of the universe. Gain a little perspective
on this expanse of time and space --the history of the cosmos.
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Follow
this timeline throughout the history of space.
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13.7
billion years ago
The Big Bang - At
the moment of the Big Bang, the Universe was infinitely
dense and unimaginably hot. In
an instant an explosion occurred simultaneously everywhere,
filling all space with energy. Unlike an explosion with
a distinct center, the Big Bang stretched space between
every object everywhere so that everything moved further
away from everything else. Cosmologists believe that all
forms of matter and energy, as well as space and time
itself, were formed in this instant. |
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One
second after the big bang
Cooling Occurs - As
the universe cools after the big bang, the fundamental
particles and energy which make up the cosmos such as
quarks, electrons, photons and neutrinos smash themsleves
together to form protons and neutrons.
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3
minutes after the big bang
The
First Atom of Helium is Created- Approximately three
minutes after the Big Bang, when the temperature fell
to one billion degrees, protons and neutrons combined
to form the nuclei of a few heavier elements, most notably
helium. For a long time, temperatures remained too high
for the formation of most other atoms we know of today.
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10
thousand years after the big bang
The Radiation Era -
At high temperatures, pressures and densities it is more
stable to produce energy than it is matter. In the early
universe, basic matter was colliding with itself and being
converted to energy faster than mass was being created.
As a result, space was made up almost entirely of energy
in the form of different wavelengths of light, X rays,
radio waves and ultraviolet rays. |
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200
million years after the big bang
The First Generation of Stars- Here
we see the oldest light in the universe. As the universe
cools --to 3000 degrees-- the atoms have neutralized and
stabilized.
It is at this time that we see the seeds that generated
the cosmic structure we see today -- including stars
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Five
billion years ago
Our Universe Started Expanding at an Accelerated Rate
- Scientists believe that approximately 5 billion
years ago Dark Matter began losing its gravitational
pull against Dark Energy's push outward.These Dark Energy
forces pulling our universe apart have been observed
as accelerating faster and faster over time.
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4.5
billion years ago
Our Solar System Was Formed - Scientists believe that
the solar system was formed when a cloud of gas and dust
in space was disturbed, maybe by the explosion of a nearby
star. This explosion made waves in space which squeezed
clouds of gas and dust. Under pressure the cloud starts
to collapse. As gravity pulled the gas and dust together
a solar nebula is formed.Under pressure and heat the gas
and dust began to stick together and form clumps with
some eventually forming planets or moons. Scientist are
studying nebulae such as the Eagle Nebula to learn more
about newly forming solar systems. |
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170,000
years ago
Supernova 1987A Explodes - Explosions of these massive
stars distribute many common elements such as Oxygen,
Carbon, Nitrogen, Calcium and Iron into interstellar space
where they enrich clouds of Hydrogen and Helium that ultimately
form new stars. They also create the heavier elements
(such as gold, silver, lead, and uranium) and distribute
these into the universe. Much of what is created in events
such as these have allowed for the proliferation of life
on our Earth. |
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100
trillion years in the future
The Stellar Era Will End - At the current rate of
expansion -- and provided the universe does not collapse
under the pull of it's own gravity -- astronomers project
that the universe will gradually disappear. The forces
of Dark Energy will expand forever, creating an increasingly
cold and empty space. When the Stelliferous Era comes
to a close, we will no longer see stars because the energy
generated in the form of stars burning hydrogen will have
dissipated from the expansion of the universe. |
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