Have you stopped counting dollars and started counting stars (I
feel something so right doing the wrong thing… the wrong thing being this
joke)? It would be impossible to count all of them, really. In fact, an
estimated septillion
stars (that gives you 1024 stars… or a 1 followed by 24 zeroes)
are said to exist in the observable universe. And no, dear reader, no
one knows how large the universe is. Much of the universe has yet to be
explored, though we aren’t aware of how much of it still needs exploring.
We know the universe is bigger than we can imagine, but at the
beginning of time, it may have been extremely small. The Big Bang Theory is
currently the most well-known and widely accepted theory on the beginning of
the universe. It tells us that the universe used to be a singularity, an
infinitely dense and infinitely hot point in space, and that the universe is
now expanding.
Although the Big
Bang Theory seems to provide a lot of answers on how the universe came to be,
it is only a theory, and scientists do not have a direct way of proving that
the Big Bang actually happened. Scientists can only look for traces or side
effects of the Big Bang in search of the truth to the origins of the universe.
The Universe is getting fatter
An important piece of evidence supporting the Big Bang Theory lies
in a discovery made by Edwin Hubble back in 1929. Hubble observed galaxies,
gathering information on their distance from the Earth. He later noticed a
red-shift in most galaxies, meaning most galaxies were moving away from us at a
rate directly proportional to their distance from us. Put simply, the farther
away a galaxy was, the faster it was moving away from us. This came to be known
as Hubble’s Law.
We aren’t in the center of the universe, though, because the
universe has no center. It isn’t expanding from a single point but it is
expanding as a whole equally in all directions. This expansion is usually
linked to the expansion of raisin bread in an oven. As the loaf expands, each
raisin will “see” the other raisins moving away. Similarly, each galaxy sees
the rest of the universe’s galaxies moving farther apart.
The Big Bang didn’t exactly start with a “bang”. Well, not in the
way we usually think. The universe did not explode; space-time expanded, and
continues to expand to this day (more on this later). So if the universe didn’t
come from an explosion, why do we still call the theory the “Big Bang” Theory?
Fred Hoyle, an astronomer and supporter of the Steady State Theory,
another theory discussing the birth of the universe, thought the Big Bang
Theory was bogus. He was the one who actually coined the term “Big Bang”,
because the event happened very suddenly, like an explosion.
The Universe is a gigantic microwave
Naturally, to say the universe is expanding implies that the
universe was once smaller. As mentioned earlier, the universe used to be
extremely small, extremely dense and extremely hot. This was proven thanks to
physicists Arno Penzias and Robert Wilson in 1965.
They were testing a microwave detector (we can’t see microwaves
because they are shorter than light waves visible to us) when the detector was
making more noise than they expected. They found bird poop in their detector,
and thought this caused the machine to malfunction, but the detector continued
making a lot of noise even after they cleaned it out. The pair eventually
learned the radiation they detected, called Cosmic Microwave Background (CMB)
radiation, was leftover heat from the Big Bang. This radiation was 2.74 Kelvin
(-270.4℃) in
temperature. It definitely doesn’t sound hot, but in the world of physics, 0
Kelvin (-273.15℃) is the
absence of heat, therefore 2.74 Kelvin is still “hot”.
The Universe was once like a (super)star
One second after the Big Bang, the universe was filled with
hydrogen atoms. These atoms then fused with another to form other light
elements, such as helium and lithium. This whole process was called the Big Bang
nucleosynthesis. A star’s core behaves similarly, producing the same
elements formed during the earliest moments of the universe. Astronomers
measured the ratios of these elements and discovered how abundant they were
around the universe, with hydrogen being the universe’s most abundant element.
Their observations matched the predictions of the Big Bang Theory, yet again
strengthening its credibility.
The Universe has stretch marks (read: Gravitational waves)
Scientists have more evidence on how the universe got fatter! On
March earlier this year, a Harvard team of astrophysicists working in the
South Pole detected gravitational waves, ripples in space-time resulting from
the Big Bang. Strong gravitational wave signals were found in the CMB
radiation mentioned earlier. These gravitational waves pave the way for the
theory of cosmic
inflation, the rapid expansion of the universe, which is said to have
happened about 10-34 seconds after the Big Bang.
Despite giving us a better insight on how the universe works, the
Big Bang Theory leaves us with unanswered questions. What happened before the
Big Bang? Was there really a time before the Big Bang? Is our universe the
first universe to ever exist, or is it a remnant of a previously existing
universe? How can something as huge and dynamic as our universe come from
nothing? These questions continue to baffle scientists, who constantly continue
to seek out answers until there’s nothing more to ask.
Has your brain exploded yet? Think of it like this: Your brain is
its own universe and experienced its own version of the Big Bang. Your brain
didn’t explode; it expanded with knowledge!
Sources:
Hawking, Stephen. A Brief History of Time: Updated and Expanded
Tenth Anniversary Edition. New York: Bantam Books, 1996. Print
Jones, Andrew. “What is Inflation Theory?” About.com. n.p.,
n.d. Web.
McKinnon, Mika. “Incredible Discovery Provides Evidence for the
Big Bang Theory.” Space io9.
n.p., n.d. Web. 17 March 2014. < http://space.io9.com/have-physicists-detected-gravitational-waves-yes-1545591865>
Pasachoff, Jay, and Filippenko, Alex. The Cosmos: Astronomy in
the New Millenium. Boston: Cengage
Learning, 2007. Print.
White, Martin. “Big Bang Nucleosynthesis.” Astronomy, UC
Berkeley. n.p., n.d. Web.
“How Many Stars are there in the Universe?.” European Space Agency. n.p., n.d. Web
<http://www.esa.int/Our_Activities/Space_Science/Herschel/How_many_stars_are_there_in_the_Universe>.
<http://www.esa.int/Our_Activities/Space_Science/Herschel/How_many_stars_are_there_in_the_Universe>.
Article by Andie
Artwork by Katrina
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Science has been Andie’s thing since she was four (she once thought the Milky Way was the gateway to heaven). She doesn’t mind being called a geek—because it’s obviously true—and is now a physicist in the making. She believes her puns, jokes and pick-up lines are amazing, even if everyone else around her doesn’t. Andie constantly thirsts for adventure, and is ready to give almost anything a try.
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