The Origin of the Universe

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The Origin of the Universe

• Massimiliano Galeazzi

Miami 20 November 2002
MALS 601
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Summary

• The Scientific method
• The view of the Universe before 1900
• The Greeks
• The Heliocentric system
• The view of the Universe after 1900
• Einstein Theory of relativity
• Beyond the solar system
• Hubble law
• The Big Bang theory

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The Scientific Method
Observations Theory Predictions Experimental
verification
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Observations
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Observations

• Sun
• Moon

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Observations

• Sun
• Moon
• Stars

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Observations

• Sun
• Moon
• Stars

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Theory
Theory 1
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Geocentric theory

• Movement is not so simple

• The movement is not perfectly periodic
• There are monthly annual and longer term changes

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Geocentric theory

• Movement is no so simple
• Planets

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Geocentric theory

• Movement is no so simple
• Planets
• Distance to the objects

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Geocentric theory
Ptolemy The Almagest A.D. c.100-c.178
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Geocentric theory
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Geocentric theory
SUN
Venus
EARTH
Mercury
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Geocentric theory
Simplicity
SUN
Venus
EARTH
Mercury
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Simpler theories
Heliocentric system the planets (including
Earth) rotate around the Sun and the Earth is
also spinning around its axisPythagoreans
Aristarchus of Samos Plato () Copernicus
Hybrid geocentric system the Earth is not
moving the planets rotate around the Sun that
rotates around the EarthHeraclides of Pontus
Tycho Brahe
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Heliocentric theory
Nicolaus Copernicus On the Revolutions of the
Heavenly Spheres 1473-1543 Johannes
Kepler Epitome of Copernican Astronomy The
Harmonies of the World 1571-1630 Galileo
Galilei Sidereus Nuncius 1564-1642
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Heliocentric theory
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The phase of Venus
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The phase of Venus
Galileo Galilei c1610
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Parallax
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Parallax
winter
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Parallax
summer
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Parallax
summer
1832 Alpha Centauri (nearest star)
Henderson Vega Friedrich von Struve 61 Cygni
Friedrich Bessel
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Beyond the solar system
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Beyond the solar system
2) The star distribution in the milky way is
asymmetric with respect to the Earth but is
rather symmetric with respect to a point in the
constellation of Sagittarius (Shapley 1915)
The Sun is not at the center of the Galaxy
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Beyond the solar system
3) There are other galaxies in the Universe in
addition to ours (Hubble)
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Beyond the solar system
4) There are billions of galaxies in the Universe
Solar System Galaxy Universe COSMOLOGY
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Doppler effect
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Doppler effect
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Doppler Effect in Galaxies
Earth
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Hubble law (redshift)
ALL DISTANT GALAXIES ARE RECEDING FROM US
Edwin Hubble 1929
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Consequences of Hubble Law
If all the galaxies move away from us does it
mean that we are at the center of the Universe
What happens if we rewind the tape of the
Universe
How old is the Universe
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Expansion of the Universe
If all the galaxies move away from us does it
mean that we are at the center of the Universe
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Expansion of the Universe
What happens if we rewind the tape of the
Universe
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Age of the Universe
speed H distance
AGE OF THE UNIVERSE IS APRROXIMATELY THE INVERSE
OF THE HUBBLE CONSTANT T 1/H
T 2 1010 years 20000000000 years
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Evolution of the Universe
What happened at the beginning What will happen
in the future

• COLD BIG BANG
• HOT BIG BANG

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The Big Bang Theory
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The Big Bang Theory
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The Big Bang Theory
Can we try to see the explosion
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The cosmic microwave background
Arno Penzias and Robert Wilson 1965 (Nobel Prize
in 1978)
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What will happed in the future
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What happened before the Big Bang