The Big Bang

How the universe began is one of the most interesting questions that
modern research has answered for us. The theory of the big bang is
accepted by nearly all of the world's scientists, due to the mound of
evidence that supports the idea. However, it was only as recent as 100
years ago that the most prominent minds in science believed that the
universe had existed in its current form forever—because if the
universe had a beginning, it must imply a creator or creating force.
Because of this, scientists began to believe the idea that the
universe was static and unchanging.

The big bang model states that the universe we see today is the result
of an infinitely dense bit of matter becoming unstable and then
exploding—hence the name, the big bang. At a single, infinitely dense
point, all the matter that exists in the universe was compressed down
to an area smaller than that of an atom. When the explosion occurred,
the universe as we know it began to form. Massive clouds of hydrogen
and helium (the first to elements present in the period table) began
to spread clumping together and forming galaxies, and the stars and
planets within them. Astronomers and phycists place the date of this
expansion as 13.73 ± 0.12 billion years ago—meaning that the universe
is slightly less than 14 billion years old.

There is a huge amount of evidence to support this theory. The first
of which emerged in 1929, being hypothesized by Edwin Hubble—the
Hubble Telescopes namesake. Hubble observed that stars and other
objects in the sky were moving away from something. After more
observational data was collected, he began to realize that the
universe is in a state of continued expansion. This theory, known as
Hubble's Law, is the first and one of the most important pieces of
evidence collected that hinted at the big bang theory.

The second, and most important piece of evidence, came in the form of
cosmic background radiation, which was first observed in the 1940s,
but was made into a formal theory in the 1960's. The discovery was
quite accidental. Two astronomers (Arno Penzias and Robert Wilson)
were working with a large radio telescope they had constructed when
they discovered a strange background noise through their device. After
readjusting and cleaning the radio telescope, the noise persisted, and
the astronomers were perplexed. After performing more research and
data collection, they determined that the noise they were hearing was
the remnants of the huge explosion in which the universe first began.