Big Bang Theory

• At one time, the universe was a dense, hot, supermassive ball.

• About 13.7-14.5 billion years ago, a violent explosion occurred sending material in all directions into space.

This marked the beginning of the universe.Eventually, matter cooled and condensed into galaxies, stars, and planets.

Big Bang and the Nebular Hypothesis: How Everything Formed- Let’s Fill Out This Chart

Name of the Step What Happened Picture/ Diagram to help you remember

1.

2.

3.

4.

5.

6.

7.

1. The Beginning- “Explosion”

• About 14 billion years ago a tightly packed, very dense, high temperature singularity exploded.

The Big Bang

2. Energy turns into matter• The universe expanded from the singularity and

starts to cool down, which allows matter to form.

Think about what happens to water at different temperatures:When it’s hot, it’s a gas.

When it’s cold, it turn into a solid.

According to this equation, as energy “cools down” (becomes less energetic) it turns into matter (stuff like dust and gas)

3. Galaxies Form

• About 13.7 billion years ago, matter started cooling down enough for galaxies to form

Galaxy Formation

Click on the link to watch the video below to see what the formation of the galaxy looks like

(at fast forward speed of course)

http://www.youtube.com/watch?v=n0jRObc7_xo

4. Nebulas form and start to spin

• Over the course of millions of years, gravity began to pull the gas and dust together.

• These clouds began to spin around the biggest clump in the center.

This is a nebula, made

of gas and dust in space.

This material will eventually

form a new star and solar

system

5. Solar Systems Form

• About 5 billion years ago a giant cloud of dust (nebula) in our galaxy collapsed to form an early version of our solar system

6. Sun Forms• The pressure

caused by gravity forces gas to come together and the Sun is born.

7. Planets Form• The remaining clumps of

gas and dust became planets. Planets collect this gas and dust as part of accretion.

• Earth formed about 4.5 billion years ago.

Formation of Planets

• The planets were formed by planetesimals(baby planets) merging together by accretion because of gravity

Formation of our solar system video:Click the link below to watch a video about

how our solar system formedhttps://www.youtube.com/watch?v=IRZ

YMimUET8

Evidence of the Big Bang

But how do we know about the Big Bang?

Evidence for the Big Bang Theory• Find this chart to fill in about the proof for the Big

Bang

Support for the Big Bang Theory

1) Red shifts- as stars move away from us, their light stretches and becomes longer, towards the red part of the spectrum

Light would

shift blue if stars were

moving towards

us

The Doppler Effect/ Red Shifts – shows us that the universe is expanding because almost everything we see is moving away from us

Evidence to Support the Big Bang

The Expanding Universe

• 1929 – Edwin Hubble found that the universe is expanding– Estimated

distances, relative brightness, Doppler red shifts

Red shifts are proof because the light that radio telescopes detect is shifted towards red, NOT to blue.

This means stars are moving away, indicating the expansion of the

universe.

Support for the Big Bang Theory

2) Cosmic background radiation

–Radio signals coming from every direction in space.

–Nearly uniform intensity and from nearly every direction

–Believed to be created by the big bang explosion.

Cosmic background radiation is proof because there is the same level of

energy wherever we look in the universe, and there could only be the same level if it came from the same

source, the Big Bang

https://www.youtube.com/watch?v=8OvcWc-xYjA

Big Bang/ Solar System Formation ProofAll planets in the solar system have orderly motions, they:

-Orbit sun in same direction (Counterclockwise as seen from the north pole)

-Lie in the same level/ orbital plane

-Travel in the same types of orbits

-Rotate in the same direction in which they orbit

…ALSO:

-Almost all moons orbit their planet in the same direction as the planet’s rotation and near the planet’s equatorial plane

-The sun rotates in the same direction in which the planets orbit

3. All planets (except Venus!) rotate in the same direction, all planets revolve around the Sun in the same direction

See how they spin. . .

See how they’re all in a row?

See how all of the planets are in a flat row?

The majority of planets and objects rotating and revolving in the same direction cannot be a coincidence,

this indicates the same force started them going in the same direction.

Exit TicketAnswer these on a piece of paper you can turn in

1. When did the Big Bang happen?

2. What is the Big Bang theory? (Write at least one complete sentence.)

3. What are the three pieces of evidence for the Big Bang theory?

4. What is happening to the universe?

5. Is the universe bigger now than it was at the start of class?