Theorethical Beginning of the Unverse: Big Bang Theory

The Theoretical Beginning
of the Universe /
Big Bang Theory

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The Beginning...

When most astronomers are asked how the Universe began,
what do you believe they say is the answer?

How long ago do
we believe the
Universe began?

The Beginning...

You were correct if you said most will say the Universe began
with the "Big Bang" which is an event said to have occurred
about 14 billion years ago.

14 Billion Years Ago

A billion years is very hard for most people to understand.

It is difficult to think of anything we can picture in terms of billions.
Lets use an example to try and understand how many one billion is.

With your group, try and
decide what size jar you
would need to hold
1 billion pennies

hint:
1 billion = 1,000,000,000

14 Billion Years Ago

Image: http://www.kokogiak.com/megapenny

One billion stacked pennies would be the size of FIVE school buses!

So if you wanted to represent
14 Billion pennies - how
many school buses would
you need?

Big Bang Theory

This theory states that all of the
mass in the universe was once
compacted into one small point
thousands of times smaller than
the head of a pin.

How is that possible?

Big Bang Theory

This one spot was also hotter
and more dense than any
object we know of today.

It is believed our Universe
began with a "Big Bang" when
this small spot had a massive
explosion.

Big Bang Theory

During the fraction of a second following the
explosion, the universe expanded rapidly.

Think about what happens when you watch
fireworks explode.

The same thing happened after the Big Bang.
Within a fraction of a second, the universe was
bigger than a galaxy and has not stopped
expanding since then.

Expanding for 14 billion years. Think back to all 70 school buses!

Big Bang Theory

You can also think of a stone
hitting the surface of a pond.

The water will ripple out from
that one point and the ripples
will expand larger and larger,
much like the expansion of
the universe.

Big Bang Theory

This theory states that every piece of matter in the universe came
from this one point ... this one explosion.

Since everything is made of matter, this means that the "stuff" that
makes up everything in the universe came from this one point in
time. Including you!

Multiple Choice

1 The initial explosion that resulted in the
creation and expansion of the universe is
known as the _____________.

• Big Bang Theory

• Milky Way

• Great Expansion

• Doppler Effect

Multiple Choice

2 Following the Big Bang, the universe:

• A expanded and then rapidly stopped expanding

• expanded and has not stopped expanding since.

• rapidly expanded and then shrunk back to its
  original size.

Multiple Choice

3 Scientists believe the Big Bang happened:

• 14 million years ago

• 14 billion years ago

• 14 triillion years ago

• within the last 3000 years

Evidence Supporting the Big Bang Theory

No people were around 14 billion years ago. So how did this
theory come about?

In the early 1900's, an astronomer*
named Edwin Hubble, discovered
that various galaxies were spreading
apart by examining the patterns he
found when tracing their locations in
the sky.

(astronomer: a scientist who studies planets, stars, and galaxies)

Evidence Supporting the Big Bang Theory

Last year, you learned it is possible to
estimate the distance a star is from
Earth by looking at its brightness.
Hubble used a number of methods to
estimate how far away each star is.

But he did much more. He used the
color of each star's light to determine
which direction they are moving...and
how fast.

Evidence Supporting the Big Bang Theory

The redder the light, the faster
away from us a star is moving.

His astonishing conclusion is that
almost all stars are moving away
from one another as if there were
a massive explosion long ago.

Scientists estimate that this occurred 14 billion years ago.

Multiple Choice

4 When looking at the night sky, the brighter stars are typically:

• farther from Earth than the dimmer stars

• closer to Earth than the dimmer
  stars.

• the same distance from Earth as all other
  stars

• constantly moving closer to Earth

Multiple Choice

5 Which best describes the Big Bang Theory?

• The universe has always been the way it is today.

• The universe began from a dying star

• The universe was created by a single explosion

• The universe is full of explosions, or "big bangs,"
  that are making it expand

Inflation Theory

While almost all scientists
believe in some version of
the Big Bang theory, that
theory only explains that there
was a rapid expansion, not
what caused it.

Inflation theory explains the
explosion itself, and is gaining
acceptance as new data is
discovered every year.

photo: NASA

"Flattening" the Universe

Inflation is said to have
"flattened" the universe and it
is easy to misunderstand
what this means.

In order to understand this,
talk with your group right now
about what happens to your
hands and feet when you
spend a lot of time swimming
in a pool. What do they look
like?

In the early stages of inflation, as the universe was very rapidly
expanding, it looked much like your fingers do when you spend
too much time in the water. Wrinkled.

Inflation filled in all those ridges and flattened the surface of the
universe, making it smooth, the way fingers revert once out of the
water.

"Flattening" the Universe

Dark Matter

The study of the universe is far from complete...there is much
more to do.

In recent years, the effect of
dark matter was discovered.
This invisible matter makes its
presence known by its effect
on the motion of the stars and
galaxies.

Right now the problem is no one knows what dark matter actually is.
Click on the image above for a 1 minute explanation of dark matter.

Dark Matter

Scientists are working hard to find
out what dark matter is.

Dark matter would slow the
spreading of the universe the same
way that a more massive Earth
would stop a ball from flying as high.

It's now estimated to make up 27%
of the mass of the universe!

Dark Energy

Counteracting the effect that dark matter has in slowing the
universe's expansion, dark energy has been discovered...and is
seen to be speeding up the expansion of the universe.

While the expansion of nearby
stars is slowing down...like a ball
would if thrown straight up in the
air, the expansion of the farthest
stars is actually speeding up!

Dark Energy

This amazed scientists as much as if you threw a baseball in the air
and when it reached the top where it should stop, it suddenly started
to go upwards faster. It doesn't seem to make sense!

Needless to say, dark energy
is also not well understood yet;
there are a lot of theories.

Dark Matter and Dark Energy

Dark energy and dark matter were
unknown 20 years ago. Now, they are
believed to make up 95% of the mass
of the universe.

Everything we thought was the
universe (i.e. the stars, planets,
gases,and galaxies) we now believe to
be only 5% of the universe.

This is said to be the golden age of cosmology, the study of the
universe. It's amazing how much more is left to be discovered and
explained.

Our Expanding Universe

According to the expanding universe theory, the space in our
universe will always continue to expand, as it always has since
the Big Bang occurred.

Stephen Hawking is one of the most
famous physicists in the world today. He
has researched and spoken on the
expanding universe.

Click here to hear Stephen Hawking talk
about this idea, the expanding universe

Improving the Big Bang Theory

Just like with many ideas in
Science, there are people who are
critical of the Big Bang.

The idea that there was a "Big
Bang" is a theory . This means that
it can not completely be assumed to
be fact, but it has not yet been
proven wrong.

(Scientists don't aim to prove
theories are true, they try to prove
theories are false!)

No matter your
beliefs, scientists
continue to hunt
for evidence of the
Big Bang Theory.

Either way, our
Universe (and
the stuff within
it!) is here today
for us to study.

The Universe

Multiple Choice

6 In addition to gravity, __________ is believed to hold
galaxies together.

• Dark Energy

• Dark Matter

• Solar Systems

• Stard

Multiple Choice

7 An idea which has not yet been proven to be true, but
has also not been disproved is known as:

• an understanding

• an idea

• a concept

• a theory

Multiple Choice

8 Scientists believe only five percent of the
universe is comprised of:

• A dark energy

• dark matter

• all known objects

• gravity

7 An idea which has not yet been proven to be true, but
has also not been disproved is known as:

A an understanding

B an idea

C a concept

D a theory

Answer

Multiple Choice

9 It is currently theorized that dark ____________
speeds up the expansion of the universe and dark
_________ slows it down.

• matter, energy

• energy, matter

• matter, gravity

• gravity, matter

Multiple Choice

10 The rapid expansion of the universe following the Big
Bang is known as:

• Flattening

• System Creation

• Inflation

• Bang Expansion