Group Name: Back BencherGroup Members

S M Manna (14203083)

Sumon Kumar Ghosh (14203098)

Imam Uddin (14203071)

MD. Sayham Khan (14203123)

MD. Yousuf Hassan (14203100)

Presentation Day: 12 March 2015

2The Big Bang

Contents• The Big Bang Theory

• The Big Bang Phase

• Expanding Universe

• Testing Big Bang Model

• Dark matter & Dark energy

• Evidence of dark matter

• After time period of Big Bang

• Life cycle of star

The Big Bang 3

The Big Bang

• The universe begins

~13.7 Billion years ago

• The universe begins as the size of a single atom

• The universe began as a

violent expansion

– All matter and space

were created from a

single point of pure energy in an instant.

Image 1: Beginning of Big Bang

4The Big Bang

The Big Bang: Phase

Phase 1

At the beginning of time, from

Complete nothingness, a cosmic

Explosion ignites.

Phase 2

The thrust from the explosion sends

Billions of tons of energy through space

And the elements begin to cool.

Image 2: Phase 1

Image 3: Phase 2

5The Big Bang

The Big Bang: Phase

Phase 3

Galaxies begin to take shape while

Still moving away from the initial

Point of ignition.

Phase 4

The universe continues to expand to

This very day.

Image 4: Phase 3

Image 5: Phase 4

6The Big Bang

Ever Expanding Universe

According to the Big Bang model,

the universe expande

d from an extremely dense and hot state and

continues to expand today.

Image 6: Ever Expanding Universe7The Big Bang

Testing the Big Bang model

• Prediction: If the universe was denser, hotter, in past, we should see evidence of left-over heat from early universe.

• Observation: Left-over heat from the early universe. (Penzias and Wilson, 1965)

Image 7: Left over heat from early universe

8The Big Bang

Testing the Big Bang model

• Prediction: A hot, dense expanding universe, should be predominantly hydrogen, helium.

• Observation: Universe is ~75% hydrogen,

~25% helium by mass

Image 8: The Sun: 74.5% H, 24% He by massImage 9: Cecilia Payne

9The Big Bang

Testing the Big Bang model

• Observation: 90% of matter is an

unknown form: Dark Matter.

• Refine: A new and unknown form of

matter exists. But its gravity

• works the same way, and its presence is

needed to explain how the universe looks.

Image 11: Vera RubinImage 10: Testing Big Bang

10The Big Bang

Expansion is accelerating

A recent discovery

and of unknown

origin, the concept of

Dark Energy is

actually an integral

part of Einstein’s

theory of gravity.

Image 12: Science Magazine

11The Big Bang

Dark Energy

73%

Normal Matter

4%

Dark Matter

23%

Figure 1: Materials of Universe 12The Big Bang

Evidence for Dark Energy -

supernovae as distance

indicators - step 1

Image 12: A dying star becomes a white dwarf.

13The Big Bang

Evidence for Dark Energy -

supernovae as distance

indicators - step 2

Image 13: The white dwarf strips gas from

its stellar companion….

14The Big Bang

Evidence for Dark Energy -

supernovae as distance

indicators - step 3

Image 14: ….and uses it to become a hydrogen bomb. Bang!15The Big Bang

Evidence for Dark Energy -

supernovae as distance

indicators - step 4

Image 15: The explosion is as bright as an entire galaxy of stars….

16The Big Bang

Evidence for Dark Energy -

supernovae as distance

indicators - step 5

Image 16: and can be seen in galaxies across the universe.

17The Big Bang

How Everything Began~ Several hundred thousand yearsafter Big Bang

• ATOMS form (specifically Hydrogen and its isotopes with a small amount of Helium.)

• The early Universe was about 75% Hydrogen and 25% Helium. It is still almost the same today.

Figure 2: Atom Formation.18The Big Bang

~200 to 400 million years after Big Bang

• 1st stars and galaxies form

Image 17: ~200 to 400 million years after Big Bang

19The Big Bang

~ 4.6 billion years ago

• Our Solar system forms

Image 18: Our Solar system forms

20The Big Bang

Misconceptions about the Big Bang

• there was no explosion; there was (and continues to be) an expansion

– Rather than imagining a balloon popping and releasing its contents, imagine a balloon expanding: an infinitesimally small balloon expanding to the size of our current universe

• we tend to image the singularity as a little fireball appearing somewhere in space

– space began inside of the singularity. Prior to the singularity, nothing existed, not space, time, matter, or energy - nothing.

21The Big Bang

Figure 3: Life cycle of a star

22The Big Bang

Big Bang evidence

1) Universal expansion and Hubble’s Law

2) 3 degree background radiation

3) Quasars

4) Radioactive decay

5) Stellar formation and evolution

6) Speed of light and stellar distances

23The Big Bang

Conclusions – Till Now• Big Bang model describes our current

understanding of the universe.

• New discoveries, such as dark matter and accelerating expansion (Dark Energy), lead us to refine our model,

but there is no crisis in our understanding (yet).

• Science is an ongoing process - forcing us to test our model through prediction and observation.

• The more tests it passes, the greater is our confidence in it.

24The Big Bang

The Future of Cosmology:

Beyond Einstein

• What powered the Big Bang?

• What Is Dark Energy?

• How did the Universe begin?

25The Big Bang

LASTLY – we are pretty sure everything has a beginning, right?

Image 20: Funny picture about Big Bang

26The Big Bang

Thanks

The Big Bang 27