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7/30/2019 Young and Hot
1/30
f Don Lincoln, Fermilab f
When the Universe Was
Young and Hot
Don Lincoln
Fermilab
f
7/30/2019 Young and Hot
2/30
f Don Lincoln, Fermilab f
Hubble Telescope This image is taken of galaxies
that are billions of light-years
away. Light takes a very long
time to travel to Earth.
Consequently, this photograph is
of the conditions that existedbillions of years ago, just a
billion years or so after the big
bang.
Astronomers have thuscreated a time machine of
sorts.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Ancient Greek CosmologyIn the beginning there was an
empty darkness. The only thing
in this void was Nyx (Chaos), a
bird with black wings. With the
wind she laid a golden egg and
for ages she sat upon this egg.
Finally life began to stir in theegg and out of it rose Eros, the
god of love. One half of the shell
rose into the air and became the
sky and the other became theEarth. Eros named the sky
Uranus and the Earth he named
Gaia. Then Eros made them fall
in love.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Familiar Cosmology
1 In the beginning God created the heaven and the earth.
2 And the earth was without form, and void; and darkness
was upon the face of the deep. And the Spirit of God
moved upon the face of the waters.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Modern Cosmology Approximately 15 billion
years ago, all of the matter inthe universe was concentrated
at a single point
A cataclysmic explosion (of
biblical proportions perhaps?)
called theBig Bangcaused the matter to fly apart.
In the intervening years, the universe has been expanding,
cooling as it goes.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Consequences of the Big Bang
Ifthe universe did come into existencethrough a cataclysmic explosion, there
should be some evidence. Three forms
which I will discuss are:
The universe should be expanding
The universe should have a measurabletemperature.
The mix of the elements should be known.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Doppler Effect
The Doppler effect says
that things moving away
from you look redder than
they would if they werent
moving. Things moving
towards you look moreblue.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Edwin Hubble
Using the Doppler effect, Edwin
Hubble discovered that objects that
were further away move away faster
(and, hence, were redder) than nearer
objects.
This discovery showed that the universe
was expanding and still provides one of
the best measurements of the age of the
universe.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Black Body Radiator
Universe
A black body radiator is one
which absorbs all light
which is incident on it. Such a body can also emit
light, if sufficiently hot.
The universe should thus
have a temperature and an
afterglow.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Afterglow From the Big Bang
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Afterglow From the Big Bang
In 1964, while working at Bell Labs, Penzias and Wilson discovered a radio
hiss that they couldnt make go away. They had (by accident!) discovered the remnant echo of the Big Bang
The universe was shown to have a temperature of 2.726K (-450 F)
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
COsmic Background Explorer
In 1992, COBE announced a
measurement that showed that
the background radiation was
not quite uniform (although
nearly so)
This measurement records
information approximately
300,000 years after the Big
Bang
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Goldilocks Effect
These three plots
show threedifferent effects,
each 10% less
than the one
larger than it.
You can see how
seeing a small
effect first
requires
removing the
bigger one.
Full, 10%, and 1%
10% and 1%
1%
Full only
10% only
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Helium Abundance in the Universe
At the late time (as we shall see) of3 minutes in the history of the
universe, atomic nuclei were
created.
Big Bang theory predicts that the
relative abundances of hydrogen
and helium were:
Hydrogen 76%
Helium 24%
Lithium 1 part per 1010 Due to nuclear fusion in stars since
the Big Bang, current abundances: Hydrogen 73%
Helium 26%
Everything else 1%
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Summary of Cosmologic Measurements
TheBig Bang theory is consistent with
observations. Specifically
Hubble Telescope can view the universe
~1,000,000,000 years after the Big BangThe COBE satellite can view the universe
~300,000 years after the Big Bang
The Hydrogen/Helium ratio can view the
universe ~3 minutes after the Big Bang
To which a particle physicist replies.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Thats cute
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
No.really..its cute
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Whats so interesting about that?
All the interesting stuff is over
by three minutes.
The universe was in a retirementhome by then.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
The reallyinteresting question
is:
What happened when the
universe was young and hot?
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
History of the
Universe
In the beginning, theuniverse was really,
really, hot.
Consequently, things
looked very different
in the beginning.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Consider an Ice Cube
Heat it and it Melts
Boils
Turns to steam
H2O breaks up into hydrogen and oxygen atoms
The electrons get ripped off the atoms and electrons and
atomic nuclei scurry around
Atomic nuclei get broken up into protons and neutrons
Protons and neutrons get ripped apart into particles
called quarks.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
The Big Question
How do you getsomething as hot
as it was during
theBig Bang?
Smash stuff
together!!
Hot!
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
E = m c2
Energy is Matter
Matter is Energy
Lots of energy makes
lots of matter
and vice versa!!!!!!
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
At Fermilab, we collide elementary
particles at unprecedented energies,
routinely recreating the conditions
fractions of a second after theBig
Bang.
In the spring of 2001, we will resumeoperations after a five year upgrade.
We will push our understanding of the
universe even further back in time.
Its gonna be cool!
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
What are we going to find?
I dont know!
Supersymmetry, Higgs,Technicolor, particles
smaller than quarks,
something unexpected?
If I knew, it wouldnt be any fun.
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Everything in the Universe
Microwave radiation
super clusters
clusters
galaxies
stars
planets
people
poodles
pigeons
pond scumpoliticians
From the primordial soup!
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Data-Model Comparison
7/30/2019 Young and Hot
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f Don Lincoln, Fermilab f
Data-Model Comparison