Post on 18-Jul-2015
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