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The Origins and End of the Universe
In the last few decades, science has evolved and we have discovered more and more about the
universe, revealing more about how the universe came about and also the various possibilities about
how it may end.
Big Bang Theory:
A Belgian priest named Georges Lemaître first suggested the big bang theory in the 1920s when he
theorized that the universe began from a single primordial atom. According to the Big Bang theory,
the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid
expansion caused the young Universe to cool and resulted in its present continuously expanding
state. Big Bang proponents suggest that some 10 billion to 20 billion years ago, a massive blast
allowed all the universe's known matter and energy--even space and time themselves--to spring
from some ancient and unknown type of energy a singular point of high density and temperatures.
The theory maintains that, in the instant--a trillion-trillionth of a second--after the big bang, the
universe expanded with incomprehensible speed from its pebble-size origin to astronomical scope.
Expansion has apparently continued, but much more slowly, over the ensuing billions of years.
Therefore, interestingly, there really wasn't any sort of explosion (or bang) as the name suggests,
but rather the rapid expansion of space and time. Like blowing up a balloon: as you blow air in, the
exterior of the balloon expands outward.
Scientists can't be sure exactly how the universe evolved after the big bang. Many believe that as
time passed and matter cooled, more diverse kinds of atoms began to form, and they eventually
condensed into the stars and galaxies of our present universe.
The Big Bang is a well-tested scientific theory which is widely accepted within the scientific
community because it is the most accurate and comprehensive explanation for the full range of
phenomena astronomers observe.
Since the 1940s, when the modern form of the theory took shape, scientists have detected radiation
from the early Universe with radio telescopes and satellites and named it cosmic microwave
background radiation (CMB). The CMB, which is formed of microwaves and radio waves, is
considered important evidence in support of the Big Bang because it matches theorists' predictions.
The idea subsequently received major boosts by Edwin Hubble's observations that galaxies are
speeding away from us in all directions, and from the discovery of cosmic microwave radiation by
Arno Penzias and Robert Wilson.
In 1992 instruments aboard the Cosmic Background Explorer (COBE) satellite, launched in 1989,
showed that 99.97% of the radiant energy of the universe was released within the first year of the
Big Bang event. This evidence seems to confirm the Big Bang theory. In March 1995 astronomers
found more supporting evidence for the big bang when they concluded that data obtained from the
space shuttle's Astro 2 observatory showed that helium was widespread in the early universe. The
Big Bang theory holds that hydrogen and helium were the first elements created when the universe
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Another prediction of the Big Bang theory is that the Universe should be receding from us.
Specifically, any direction we look out into space, we should see objects moving away from us with a
velocity proportional to their distance away from us, a phenomenon known as the red shift. Red shift
is thought to be evidence of the Big Bang.…read more
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Fred Hoyle, Thomas Gold, Hermann Bondi and others as an
alternative to the Big Bang theory. In steady state views, new matter is continuously created as the
universe expands. There is no beginning and no end.
The steady state theory asserts that although the universe is expanding, it nevertheless does not
change its appearance over time; it has no beginning and no end.…read more
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If the universe is finite in extent and the expansion speed does not exceed the escape velocity, then
the mutual gravitational attraction of all its matter will eventually cause it to contract. While the early
universe was highly uniform, a contracting universe would become increasingly clumped. Eventually
all matter would collapse into black holes, which would then combine, producing a unified black hole
or Big Crunch singularity. The Big Crunch will result in very high temperatures.…read more