Big Bang Theory

The Formation of the UNIVERSE!!!

THE BIG BANG THEORY

• The idea that the universe is expanding

and was once compressed in one small point

• Our best guess (so far) at how our universe began

• George Lemaitre proposed this idea in 1927.

• This idea was NOT accepted at first

EVIDENCE FOR THE BIG BANG THEORY

• Scientists found cosmic background radiation –

this tells us that some large “explosion” must have
happened to leave all that radiation behind

• Edwin Hubble observed that other galaxies

were moving away from each other

HOW IT ALL HAPPENED:

• It didn’t all happen at once – but it happened FAST!

• The next slides contain steps describing how the

universe evolved to be the way we observe it today

STEP 1:

• Time and space begin.

• Everything quickly expands everywhere

from one tiny, microscopic point

Time:

10-43 seconds

STEP 1:

STEP 2:

• The universe is “quark soup”.

• It is very hot, and only quarks –

and some electrons – exist now.

• Visible light does not exist.

Time:

10-32 seconds

STEP 2:

STEP 3:

• Things have begun to cool down,

slow down and stick together

• Quarks collide & stick together

to form protons & neutrons

Time:

1 second

STEP 3:

ONLY ONE SECOND
HAS PASSED SINCE THE BEGINNING OF EVERYTHING

STEP 4:

• Gravity causes electrons to collide with

protons and neutrons to form the first atoms -
Hydrogen & Helium

• The fusion of these particles creates light.

(this is also what makes stars shine)

Time:

3 minutes

STEP 4:

STEP 5:

• Gravity causes Hydrogen and Helium molecules

to condense into clouds

• Under great pressure from gravity, stars form in

dense areas of these gas clouds

• This process created galaxies made up of billions

and trillions of stars

Time:

300,000 years

STEP 5:

STEP 6:

• Gravity causes galaxies to collide and cluster together

• Old stars die, spewing gas and dust back

into space to form new stars –
some denser stars form black holes.

Time:

1 billion years

STEP 6:

WHAT IS GRAVITY??

A force which attracts the center of
mass of an object to other objects

(it doesn’t just pull things down)

Gravity

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KeslerScience.com

(more mass = more gravity)

Everything has gravity, HOW MUCH it has

depends on its MASS!

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Gravity

Did you know?

Gravity is the force that keeps us grounded on Earth. It is what makes objects fall towards the ground and keeps the planets in orbit around the sun. Without gravity, everything would float away!

Gravity was first described by Sir Isaac Newton in his famous law of universal gravitation!

Gravity

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KeslerScience.com

The Sun’s gravity is part of what keeps the planets in orbit around the sun!

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The Law of INERTIA

" An object in motion will remain in motion, and an object at rest will remain at rest - unless acted on by an outside force"

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The soccer ball will not move unless something moves it, and will keep rolling until something stops it.

Inertia

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KeslerScience.com

Inertia helps the planets stay in orbit around the sun



*without inertia, gravity would just pull the planets into the sun, and the moon would crash into Earth!

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Multiple Choice

True or False: Gravity is what makes the planets orbit the Sun.

• True

• False

Multiple Choice

True or False: Gravity is the only force that makes the planets stay in orbit the Sun.

• True

• False

GRAVITY

caused gas and dust to clump together more and more until it pressed so hard that it BURNED and made a STAR!!!!

​This Hubble Deep Field image shows over 10,000 stars!

Multiple Choice

Which scientist proposed the idea of the Big Bang Theory?

• Georges Lemaître

• Edwin Hubble

• Albert Einstein

• Isaac Newton

The Birth of the Universe

• STEP 1: Time and space begin. Everything quickly expands everywhere from one tiny, microscopic point. Time: 10-43 seconds

• STEP 2: The universe is 'quark soup'. It is very hot, and only quarks – and some electrons – exist now. Visible light does not exist – no stars yet. Time: 10-32 seconds

• STEP 3: Things begin to cool off, slow down, and stick together. Quarks collide & stick together to form protons and neutrons. Time: 1 second

Multiple Choice

What is happening during Step 3 of the birth of the universe?

• The universe is expanding rapidly

• Visible light starts to exist

• Quarks collide and stick together to form protons and neutrons

• Time and space begin

The Birth of the Universe

• STEP 3: Only One second has passed since the big bang began

• STEP 4: Electrons collide with protons and neutrons to form the first atoms - Hydrogen & Helium, creating light

• STEP 5: Gravity causes gas clouds to condense, forming stars and galaxies

• STEP 6: Galaxies collide, stars die, and new stars form, including black holes

• Gravity: A force that attracts objects towards each other

Multiple Choice

What formed approximately 1 second after the Big Bang?

• Quarks

• Protons & Neutrons

• Atoms

• Stars

Multiple Choice

How long did it take for the first atoms to form?

• 3 seconds

• 3 minutes

• 1 million years

• 14 billion years

Multiple Choice

What is the force that attracts objects towards each other?

• Gravity

• Inertia

• Strong Force

• Weak force

Multiple Choice

What force keeps planets in orbit around the sun (rather than just crashing into it)

• Gravity

• Inertia

• Strong force

• Weak force

Multiple Choice

Which scientist proposed the Big Bang Theory?

• Albert Einstein

• Edwin Hubble

• Sir Isaac Newton

• Georges Lemaitre