This document provides an overview of the size and evolution of the universe from the perspective of Earth. It begins with a description of the solar system and Milky Way galaxy before expanding out to discuss the immense size of the observable universe. The remainder of the document discusses the history of cosmological theories about the origin and structure of the universe from ancient cultures through modern times. It outlines the progression from geocentric to heliocentric to modern Big Bang models, highlighting evidence like galaxy redshifts that support an expanding universe evolving over billions of years.

1. A walk through the Universe
Presented by:
Teresa Cudal
Science Teacher

2. THE EARTH
We are
here

3. The Solar
System

4. 4
THE MILKY WAY(Our Galaxy)
A hundred, thousand, million stars!

5. 5
THE LOCAL GROUP OF GALAXIES
Andromeda is
the nearest big
galaxy to the
Milky Way
Milky
Way

6. 6
THE UNIVERSE IS MIND-BOGGLINGLY BIG!
• The Sun is about 150 000 000 km away from Earth
• Bright stars in the night sky are about 1000 000 (1
million) times as far away as the Sun.
• The near galaxies are about 100 000 times as far
away as the bright stars.
• 15 000 000 000 000 000 000 km

7. 7 NASA
SO HOW THE UNIVERSE COME TO BE?
THE UNDERSTANDING OFTHE ORIGIN,
EVOLUTION, STRUCTUREAND FATE OFTHE
UNIVERSE IS CALLED COSMOLOGY

8. Universe models formed in many cultures
Cosmology through the ages…

9. Rigveda
The earliest musing about the origin of the universe wherein
the Indians believes that the universe had an origin and
pondered about how and where the world and everything
began
Indian

10. Greeks
“Cosmos always exist, it is neither created nor
perishable, it is timeless and infinite”
Philolaus- Earth was not the center of the universe but it is it’s central fire.
Aristarchus- Earth is the center of the solar system but the
sun is the central fire
Aristotle –Geocentric cosmology
Albert Einstein- Theory of relativity, the universe was
a finite and static close 4-dimensional sphere

11. 2nd Century: Claudius Ptolemy (Physics of Aristotle)
Model: Earth-centered Cosmology
Big Idea: Different laws for Earth and the cosmos
Astronomy has seen 3 scientific revolutions in cosmology
16th Century: Nicolaus Copernicus (Physics of Newton) Model: Sun-centered Cosmology
Big Idea: Universal physics; same laws everywhere
20th Century: Edwin Hubble (Physics of Einstein)
Model: Big Bang Cosmology
Big Idea: Universe is changing, evolving

12. …“the natural motion of the Earth ….is towards the center of the universe;
that is the reason it is now lying at the center.”
Aristotle, On the Heavens
Earth-centered Cosmology: Claudius Ptolemy, 100-170 AD

13. Prediction: Future planetary positions
Observation: retrograde motion of planets
Refine: epicycles
Success! For 1500 years
Testing the Earth-centered model

14. Sun-centered Cosmology: Nicolaus Copernicus 1473-1543
“At rest, however, in the middle of everything is the Sun.”
Nicholaus Copernicus, de Revolutionibus

15. Big Bang Cosmology: Albert Einstein (1879-1955)
“A human being is part of a whole, called by us
‘universe’, a part limited in time and space.”

16. Evidence for an expanding universe
The spectrum of hydrogen gas is the unique
fingerprint of that element
Hydrogen lamp

17. Evidence for an expanding universe
Orion Nebula
When we see a repeat of the pattern we saw in
the lab, we know hydrogen is present

18. Evidence for an expanding universe
We see the same repeating pattern of lines in
a galaxy, but displaced to the red
Galaxy UGC 12915

19. Evidence for an expanding universe
The further the galaxy,
the more the shift to the red
Galaxy UGC 12508

20. Evidence for an expanding universe
Galaxy KUG 1750
The greater the red shift,
the faster the galaxy is receding

21. Evidence for an expanding universe
The red shift is caused
by the expansion of space.
Galaxy KUG 1217

22. Evidence for an expanding universe
The red shift is evidence
for an expanding universe
Galaxy IRAS F09159

23. Prediction: An expanding universe is evolving over time. If we look at the
early universe, it should appear different.
Observation: Distant galaxies less evolved, physically and chemically.
Testing the Big Bang model

24. 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.
Testing the Big Bang model
Vera Rubin

25. Observation: Expansion is accelerating.
Refine: Extra energy content.
A recent discovery and of unknown
origin,the concept of Dark Energy is
actually an integral part of Einstein’s
theory of gravity.
Testing the Big Bang model

27. History of the Universe

28. Planck Era
-Beginning of the universe-
The universe is made up of an atom with condensed energy
and 10 -43 year old with a unified force called the “super
force”(Gravity, strong and weak nuclear force and
electromagneticforce)
In this era, the gravity “frozen out from the super force that
shapesthe universe.

29. Grand Unified Theory Era
Began when the super force splits into gravity
and GUT force
In this time when the universe had cooled to 1029K the strong
nuclear force started to freeze out that result to the release of
large amount of energy causing space evolution that results to
expansionofuniverse(inflation)

30. Electroweak Era
-young universe-
The universe continue to expand and cool with a temperature
drop of 1015 K that causes on the freezing out of
electromagneticforceandweaknuclearforce.
At the end of the era all fundamental
forces in the universe forever distinct.

31. Particle Era
Formation of particles
Spontaneouscreationandannihilationofparticleshappened.
Near the end of the era, the temperature of the universe was
low enough for the quarks to combine in groupd of three
(protonsandneutrons)

32. Era of Nucleosynthesis
Formation of heavier nuclei to form fusion of protons and
neutron. At this stage the universe was about 3 min. old and
contain 75% H and 25% He with traces of deuterium and
Tritium

33. Era of atom and Galaxies
Formation of first generation stars within the clouds which
transformsintogalaxies.

34. The universe was about 1 billion years
old when young galaxies started to
form. Continuous creating or bursting
of stars provide the energy that lead to
the production of elements that are
used in the formations of the planets