Download - The Fallacy of Fine-tuning
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Vic Stenger
The Fallacy of Fine-TuningHow the Universe is
Not Designed for Life
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Is the universe fine-tuned for life? Penrose: 1/10123
Anthropic principle.
If the constants of physics had been slightly different, life as we know it would not have evolved.
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Some obvious fallacies of fine tuning claims
Speed of light cPlanck's constant hGravitational constant G
Arbitrary constantsjust establish system of units
Only meaningful parameters are dimensionless ratios
Fine tuned?
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Another trivial fallacy
Masses of neutrinosClaim: If slightly bigger or smaller stars and galaxies would not form in ways conducive to life.Assumes number of neutrinos is fixed. Not! Number of neutrinos depends on mass of neutrino. Higher masssmaller number.
Gravitational effect same for wide range of masses.
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Hoyle coincidenceHe4 + He4 -> Be8Be8 + He4 -> C12
Hoyle 1953
Be8 + He47.6447.68
7.3667MeV
Livio et al 1989T = 1.393 billion degrees
More carbon
Prediction!
No fine tuning evident
Synthesis of carbon in stars
Carbon energy levels
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Strength of Nuclear Force
But this assumes EM strength = constant = 1/137
S lowerno stable nuclei
S higherno hydrogen
S
forbidden
forbidden
allowed
Allow to vary
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How fine-tuned is our universe?Four dimensionless parameters determine major large-scale features of universe:
Ratio of electron to proton masses me / mp
Strength of electromagnetic force G =
Gmp2c Strength of gravity
S Strength of strong nuclear force
Note: gives proton mass
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Other forms of life
Some other form of life might be possible with many other variations of physical constants.
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MonkeyGod
Generates universe for given set of parameters.
Can run from my web site
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Num
ber o
f uni
vers
es0
2
4
6
8
10
-10 0 10 20 30 40
logarithm of stellar lifetime in years
10 billion yearsGenerated 100 random universes.
Most universes have stars with long lives (> 1 By) needed for evolution of complex elements.
20 % universes "livable"
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Extreme examples
Without which it is claimed any form of life would be impossible.
Ratio of electron to protons! 1/1037Ratio of e-m force to gravity! 1/1040Expansion rate of the universe 1/1055Energy density of the universe! 1/1059Cosmological constant 1/10120
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Ratio of number of electrons to number of protons
in universe
Just what it should be if total electrical charge of universe is
Which is just what it should be if the universe came from nothing (zero charge).
ne = np
zero
Not fine tuned.
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Gravity and electromagnetism
= 1039 Weyl 1919: Why so big?
is big because masses of particles are smallN1
r
protonelectron
Let m1 = m2 = 1.85x109 kg FEFG
= 1Then
Not fine tuned.
N1 =FEFG
=kEe2r2
G mpmer2=
kEe2Gmpme
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Energy density of the universem
M
a
v
Just what you expect if the universe came from nothing (zero energy).
E = 12 mv2
GmMa =
12 mk
Data: k = 0E = KE + PE = 0
Not fine tuned.
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Expansion rate of the universem
M
a
v
Expansion rate depends on critical density
H = 1adadt Hubble parameter
H 2 = 83 KE ka2
Data: k = 0 H 2 = 83 KE critical density
Not fine tuned.
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Cosmological constant
1ad 2adt 2 =
4G3 mat + 2rad( ) +
3 Friedmann equationc = 1
Cosmol. constant
3 =83Gvac vacuum energy density
dark energy?
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120 orders of magnitude lower
dN = gh3 d3kd 3x
x
kphasespace
Energy of the vacuum
Worst calculation in
physics history!
vac =
dEdV
= 12
gh3
d 3k
Assume zero-point energy of particle fields
+ bosons- fermions
=
g16 23c3
Ecutoff4
Ecutoff = Planck energy
vac = 10124 eV
cm3 Observed value < 104
eVcm3
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Solving cosmological constant problem
Supersymmetry:ZPE of fermions and bosons exactly cancel
Anthropic principle: multiple universes
SUSY broken in current universe
Ecutoff = 1 TeV vac = 10
64 eVcm3
Only 60 orders of magnitude off!
Include negative energy statesZPE= 0
but...
Early universe?
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WAS THE UNIVERSE CREATED FOR LIFE?
The galactic space around Earth is probably not teeming with complex life
Earth is only known planet with life
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The underprivileged planet
Earth is not all that well suited for human life oceanWe are restricted to surface Atmosphere does not block UV Natural disasters, disease, famine kill
thousands yearly
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An intelligent designer with special regard for humanity would have done a much better job.
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Wasted Space
Distances are immense
Nearest star: 4.22 light-years Nearest galaxy: 2.44 million light years Galaxies within our horizon are now 40
billion light-years away
Universe beyond horizon: 10 to the 10 to the 100 times bigger
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Wasted time
Universe 13.7 billion years old Earth 4.5 billion years oldModern humans 150 thousand years old
0.001 %
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Wasted Matter
Most of the matter of the universe is not atomicthe component of life
Visible atomic matter in galaxies: 0.005 of mass of universe.
Total carbon: 0.0002 Dark matter: 0.22 Dark energy: 0.74
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Wasted energy
Only two photons of every billion emitted by sun are used to warm Earth
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A tiny pocket of complexity
Most of universe is in random motion
Cosmic microwave backround
Photons are a billion times more numerous than atoms
Random to one part in 100,000
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Humans in space
Humans cannot live in space or on any known planet or moon without extensive life support.
Cosmic radiation prevents humans from spending years in space.
Even so-called earth-like planets are not likely to be able to support human life.
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We are marooned on spaceship Earth
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The universe shows no evidence of being designed with humans in mind
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Are we doomed to extinction?
Yes, as a species.
But, perhaps our successors will carry on.