Transcript High Resolution Detectors for the Study of the Diffuse X

The Origin of the Universe
Massimiliano Galeazzi
MALS 601
Miami, 20 November 2002
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
The Scientific Method
Observations
Theory
Predictions
Experimental verification
Philosophy
Observations
Theory
Observations
• Sun
Predictions
Experimental verification
Observations
Theory
Observations
• Sun
• Moon
Predictions
Experimental verification
Observations
Theory
Observations
• Sun
• Moon
• Stars
Predictions
Experimental verification
Observations
Theory
Observations
• Sun
• Moon
• Stars
Predictions
Experimental verification
Observations
Philosophy
Theory
Theory 1
Theory
Predictions
Experimental verification
Theory 2
Observations
Philosophy
Geocentric theory
Theory
Predictions
Experimental verification
• Movement is not so simple
• The movement is not perfectly periodic
• There are monthly, annual, and longer term changes
Observations
Philosophy
Predictions
Geocentric theory
• Movement is no so simple
• Planets
Theory
Experimental verification
Mars
Observations
Philosophy
Geocentric theory
• Movement is no so simple
• Planets
• Distance to the objects
Theory
Predictions
Experimental verification
Observations
Philosophy
Geocentric theory
Theory
Predictions
Experimental verification
Ptolemy, The Almagest,
A.D. c.100-c.178
Observations
Philosophy
Geocentric theory
Theory
Predictions
Experimental verification
Observations
Philosophy
Geocentric theory
SUN
Venus
EARTH
Mercury
Theory
Predictions
Experimental verification
Simplicity
Philosophy
Geocentric theory
SUN
Venus
EARTH
Mercury
Observations
Theory
Predictions
Experimental verification
Observations
Theory
“Simpler” theories
Predictions
Experimental verification
Heliocentric system: the planets (including Earth) rotate
around the Sun, and the Earth is also spinning around its
axis
Pythagoreans, Aristarchus of Samos, Plato (?), Copernicus
“Hybrid” geocentric system: the Earth is not moving, the
planets rotate around the Sun that rotates around the Earth
Heraclides of Pontus, Tycho Brahe
Observations
Theory
Heliocentric theory
Predictions
Experimental verification
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
Observations
Theory
Heliocentric theory
Predictions
Experimental verification
Observations
Theory
Predictions
The phase of Venus
Experimental verification
Observations
Theory
Predictions
The phase of Venus
Galileo Galilei, c1610
Experimental verification
Observations
Theory
Predictions
Parallax
Experimental verification
Observations
Theory
Parallax
Predictions
Experimental verification
winter
Observations
Theory
Parallax
Predictions
Experimental verification
summer
Observations
Theory
Parallax
Predictions
Experimental verification
summer
1832
Alpha Centauri (nearest star), Henderson
Vega, Friedrich von Struve
61 Cygni, Friedrich Bessel
Beyond the solar system
1) High concentration of stars along the milky way
 The stars are distributed more in a disk than in as sphere
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
Beyond the solar system
3) There are other galaxies in the Universe in addition to ours
(Hubble)
Beyond the solar system
4) There are billions of galaxies in the Universe
 Solar System  Galaxy  Universe
 COSMOLOGY
Doppler effect
Doppler effect
Doppler Effect in Galaxies
Movement
Earth
Fast
toward us
Slow
toward us
Not moving
Slow
away from us
Fast
away from us
Observations
Theory
Hubble law (redshift)
Predictions
Experimental verification
ALL DISTANT GALAXIES ARE RECEDING FROM US
Edwin Hubble
1929
 Speed = H · distance (H = Hubble constant)
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?
Expansion of the Universe
If all the galaxies move away from us, does it
mean that we are at the center of the Universe?
Raisin Cake
Balloon
Expansion of the Universe
What happens if we rewind the tape of the Universe?
REWIND
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 = 20,000,000,000 years
Observations
Theory
Evolution of the Universe
Predictions
Experimental verification
What happened at the beginning?
What will happen in the future?
• COLD BIG BANG
• HOT BIG BANG
Observations
Theory
The Big Bang Theory
Predictions
Experimental verification
Observations
Theory
The Big Bang Theory
Predictions
Experimental verification
Observations
Theory
The Big Bang Theory
Predictions
Experimental verification
Can we try to “see” the explosion?
YES!!!
Speed of light: 300,000 Km/s ~ 675,000,000 Miles/h
distance = 20,000,000,000 light years
~100,000,000,000,000,000,000,000 Miles
Observations
The cosmic microwave
background
Theory
Predictions
Experimental verification
Arno Penzias and Robert Wilson, 1965
(Nobel Prize in 1978)
What will happed in the future?
What happened before the Big Bang?
?
Philosophy