The document discusses the origins and evolution of the universe, Earth, and life. It describes how the Big Bang created the universe approximately 13.7 billion years ago. It then explains how galaxies, stars, and planets formed, including theories about how the solar system originated. The formation and geological history of Earth is covered in detail, breaking its timeline into Precambrian, Paleozoic, Mesozoic, and Cenozoic eras. Key events like the emergence of life and mass extinctions are highlighted.

1. Presented by
Mohit kumar
Pankaj
Arun kumar
Ankit srivastava
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4. BIG BANG THEORY
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5. BIG BANG
EXPANSION
APPROXIMATELY 13.7 BILLION YEARS AGO
 The whole universe was compressed into the confines of an
atomic nucleus. Known as a singularity, this is the moment
before creation when space and time did not exist.
 According to the prevailing cosmological models that
explain our universe, an ineffable explosion, trillions of
degrees in temperature on any measurement scale, that was
infinitely dense, created not only fundamental subatomic
Particles and thus matter and energy but space and time
itself. These events was occurred are termed as Big bang.
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6. ORIGIN OF GALAXIES
Gravity makes hydrogen
and helium gas coalesce
to form giant clouds that will
became galaxies, smaller
clumps of gas collapse to
form the first stars.
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7. ORIGIN OF SOLAR SYSTEM
There are three theories regarding the origin
of the solar system:-
Nebula hypothesis
Collision or encounter
hyothesis
Planetesimal hypothesis
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8. NEBULA HYPOTHESIS`
Planets and their satellites
were formed at same time as
the sun. Space was filled by a
rotating cloud (nebula) of hot
gas and dust, as it cooled
began to contract
Note:
It is most acceptable theory,
as its modification has been
made.
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9. Drawbacks of nebula hypothesis
• The mass of material in each ring would be too
small to provide the gravitational attraction
needed to cause the ring to condense into a
planet.
• As the nebula contracted, the largest part of the
angular momentum would remain associated
with the main mass that condensed to form the
Sun, which disagrees with the observed
distribution of angular momentum in the solar
system.
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10. COLLISION OR ENCOUNTER
HYPOTHESIS
It assumed that the Sun was
formed before the planets.
The gravitational attraction of a
closely passing star or the blast
of a nearby supernova
explosion drew out a filament
of solar material that
condensed to form the planets.
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11. Drawbacks of collision hypothesis
The solar material would have been so hot
that it would dissipate explosively into space
rather than condense slowly to form the
planets.
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12. PLANETESIMAL HYPOTHESIS
 The discredited theory that the close
passage of a star to the sun caused many small
bodies (planetesimals) to be drawn from the
sun, eventually coalescing to form the planets.
 The planets and satellites of the solar
system were formed by
gravitational aggregati-
on of planetesimals.
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13. ORIGIN OF THE EARTH
There are several formation process took
place resulting in the origin of the earth:-
• Crust, mantle and core formation.
• Atmosphere formation
• Hydrosphere formation
• Lithosphere formation

14. The Age of the Earth
4.6 billion years old
=
4,600,000,000
Image courtesy of NASA, http://en.wikipedia.org/wiki/Image:The_Earth_seen_from_Apollo_17.jpg#file

15. EARTH HISTORY
GEOLOGICAL
TIME SCALE
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16. The earth’s 4.6 billion
year history is divided
into major units of time:
Precambrian Time
Paleozoic Era
Mesozoic Era
Cenozoic Era
Image created by Jason Brechko for Lake George Association (Lake George, NY)
http://www.lakegeorgeassociation.org/geology_facts.htm
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17. Precambrian Time
• 4.6 billion years before present to
544 million years before present
• Longest era with a sparse fossil
record
• Origin of earth’s crust, first
atmosphere, and first seas
• Earliest fossils of cyanobacteria use
photosynthesis to produce oxygen
• Ozone layer in the atmosphere is
formed from oxygen
Image courtesy of http://www.sharkbay.wa.gov.au/tourism/what_to_see_and_do/images/stromatolites_lge.jpg
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 17

18. Paleozoic era
• 544 million years before present to
245 million years before present
• Marine communities flourish
• Early fishes develop
• Origin of amphibians, insects &
reptiles
• Recurring ice ages/ Appalachians
mountains form
• Spore-bearing plants dominate
Images courtesy of: http://discover.edventures.com/images/termlib/p/paleozoic/support.gif,
http://en.wikipedia.org/wiki/Trilobites
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 18

19. Paleozoic era
(continued)…
• 286 - 248 million
years before present: c
Supercontinent of
Pangea forms
• 248 million years
before present:
MASS EXTINCTION-
90 % of all known
families lost!
Image courtesy of http://www.ig.utexas.edu/research/projects/plates/teaching_ideas.htm?PHPSESSID=def1b9
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 19

20. Mesozoic Era
• 245 million years before present - 65
million years before present
• The age of the dinosaurs!
• Gymnosperms dominate land plant/
origin of angiosperms - flowering plants
• Origin of mammals & birds
• 145 million years before present -
asteroid impact? MASS EXTINCTION
• Pangea begins to separate/ Rocky
mountains form
Image courtesy of http://nascarulz.tripod.com/dinomain.html
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 20

21. 65 million years
before present….
• ASTEROID IMPACT!
• Mass extinction of
ALL dinosaurs and
many marine
organisms
• End of the Mesozoic
era
Image courtesy of NASA: http://www.nasaexplores.com/show2_912a.php?id=01-074&gl=912
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 21

22. Cenozoic Era
• 65 million years before present -
today
• Present era we live in
• Continued evolution and
adaptations of flowering plants,
insects, birds, mammals
• Mammals dominant
• Major crustal movements &
mountain building (Alps &
Himalayan mountains form)
Image courtesy of: http://www.karencarr.com/gallery_Cenozoic_arch.html
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 22

23. And during the
•
Cenozoic era…
The most primitive hominid
(human ancestor) evolves -
approximately 4.4million years
before present
• The first modern humans (homo
sapiens) evolved approximately
100,000 years before present
Image courtesy of: http://www.wilderdom.com/images/evolution/8.jpg

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