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TRANSCRIPT
Fundamental Physics and the Big Questions
Ian Bryce, BSc (Physics), BE(Hons) [email protected]
www.hsnsw.asn.au
Presentation as at 3 October 2015
How science has answered or recast many of the famous questions of philosophy.
A: Traditional Questions about the Universe
B: Questions about Life and Mind
D: New questions which arise from science
E: Questions about Philosophy itself
What questions will we address?
C: Questions about The Spiritual and Ethics
Evidence
Answers
Question
Analysis
Our basic method
What questions will we address?
• What makes the crops grow?
• Where did the universe come from?
• Is there a Purpose?
• How does the universe work?
• Where will the universe end up?
A: Questions about the Universe
Questions about Life
• Where did life come from?
• Where did humans come from?
• How does the mind work?
• Do we have Freewill?
• Is what happens in the universe predetermined?
• Is there a purpose to life?
B: Questions about Life and Mind
C. About the Supernatural
• What is spirit? What is the soul?
• The Afterlife?
• Are there gods?
• How does prayer work?
• Angels and demons?
• Where do ethics come from?
• What are human rights?
• Animal rights?
C: Questions about the Spiritual and Ethics
• Quantum Mechanics
• The ultimate theory of physics?
• Dark Matter?
• Dark energy?
• The eventual fate of the universe?
• Is the universe infinite?
• Does it have an edge?
• Black Holes?
• Before the Big Bang?
D: New questions which arise from science
E: Questions about Philosophy itself
• What is Philosophy? The application of pure thought to the solution of questions
• Can reason alone lead to any conclusion about the real world?
• Should it take into account the findings of science?
• What about Metaphysics?
Philosophers have debated such Big Questions for millennia.
• Many questions have been answered. • Some questions have been reformulated. • Some questions remain unanswered.
After going through the evidence, we will re-examine these mysteries.
But first, to set the scene…
When you travel…
Which method do you use?
IMMATERIAL
MATERIAL
When you communicate…
Which method do you use?
IMMATERIAL
MATERIAL
But hang on…This is showing a tension between spiritual beliefs and science.
Perhaps they can BOTH exist in harmony?
Relation between the immaterial (pseudoscience)
and the material (science)
“Science and religion are Non-overlapping
Magisteria”
– Steven J Gould
“There is a single light of science, and to brighten it anywhere is to brighten it everywhere.” - Isaac Asimov
It is called the scientific method.
• One method is far more effective than any other, in finding the truth.
• It has revealed the origins of the universe,
• of our planet,
• of life,
• and of humans.
The scientific method
Science combines two elements:
• Observation or testing (gathering evidence)
• Analysis (using known data and applying theory)
Also, philosophy helps us to place that knowledge in our intellectual framework.
A: Questions about the Universe
Where science comes from. Many researchers, many countries, hundreds of years, constant checks
The universe through time
Enlightenment through science Cosmology has revealed the beginning of the
universe
• The big bang
The first generation of stars
Formation of the Elements #1
1. Hydrogen (H) nucleus – protons – from the quark-gluon plasma, at about 3 minutes
Quark-gluon plasma cooling protons
Formation of the
elements #2
Inside stars
Heavier elements (more later)
As these nucleii cooled, they collected
electrons to form neutral atoms
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• These atoms formed gas and dust.
• They drifted around in space, until they clumped together by gravity
Enlightenment through science • The clump grows,
and a new star forms at the center
Enlightenment through science
• The surrounding disk clumps into planets
Enlightenment through science • Leftover material clumped into: MOONS
Enlightenment through science • Leftover material clumped into: RINGS
Enlightenment through science • Leftover material clumped into: ASTEROIDS
Enlightenment through science • Leftover material clumped into: COMETS
When formed 4.5 billion years ago, the earth is molten rock
When it cools about 3.7 billion years ago, comets bring ice
For a video on comets, see https://www.youtube.com/watch?v=fGTq14qCwJk
Enlightenment through science • Conditions stabilize
Enlightenment through science • Life began, when a replicating molecule arose
• (no trace left now - possibly related to RNA )
Enlightenment through science • Fish and Reptiles evolved
Enlightenment through science • Then came Mammals
Enlightenment through science • Homonids
Enlightenment through science • And eventually Homo Sapiens - intelligent
Intelligent enough to (eventually) invent science
More on that next week…
What has science found out, at a fundamental
level?
Map of physics
Fundamental Physics
Standard Model of Particle Physics
Quantum Mechanics
General relativity
Elementary Particles
Quarks
Gluons, photons
Electrons etc
The four forces
Gravity
Electromagnetism
Weak interaction
Strong interaction
Compound particles
Proton
Neutron
Mesons etc
Atoms
Nucleus + electrons + QM
Molecules
Assemblies of atoms Matter
Complex assemblies of atoms and molecules
Other sciences
A map of physics © Ian Bryce 2014
Evolution of
the universe
These four forces account for everything we see happening in the universe (at the most fundamental level)
THERE ARE APPARENTLY NO GAPS
What about Quantum Mechanics?
Is there a bridge joining classical mechanics to quantum mechanics?
A: Classical Mechanics
Lagrangian
Eg orbiting body
L = T – V = ½ m v2 - GMm/r
Put L in a classical formula, solve,
gives classical motion of planet or electron
B: Quantum Mechanics
Same Lagrangian
Eg orbiting body
L = T – V = ½ m v2 - ɛQq/r
Put L in Schrodinger’s Equation, solve,
Gives quantum solution of atom
Quantum Mechanics Quantum
solution of a hydrogen
atom
Top left – ground state
Others – excited states
Excited states and light emission
Different atoms give different wavelengths (colors)
Light Sources demonstration
• Sun (black body 6000K)
• Candle, filament (black body 3000K)
• Salt in a candle – sodium (electron transition)
• LED (single color)
• LED (white)
• Laser (stimulated emission, single wavelength)
• Compact Flourescent (many discrete wavelengths)
These light sources cannot be explained in terms of classical physics. Quantum mechanics is required.
LED’s and TV’s
Quantum Molecules
Quantum Molecule - hydrogen
Quantum molecule - Electron Cloud Impossible to draw!
Stick models (easier to draw).
Caffeine!
Stick model. DNA.
Watson and
Crick
Quantum Molecule – DNA
Quantum Solids
Science has a good understanding of the universe,
and the matter in it. At least in the here and now.
How complete is science’s knowledge
of how the world works?
Narrative: Your car won’t start…
Your reactions illustrate that THERE ARE NO GAPS
IN HOW THE WORLD WORKS* *At least in the here and now
We have had a tour of science…
Now we can revisit some Big Questions…
Traditional Questions about the Universe
What makes the crops grow?
• Nutrients from the atmosphere
• Nutrients from the soil
• Water
• Sunlight
• Propagation by seeds, cuttings etc
ANSWERED BY SCIENCE
Traditional Questions about the Universe
Where did the universe come from?
• Traced all the way back to the big bang at least 10-32 seconds)
• Its origin is still unknown (some theories later).
Largely answered.
Traditional Questions about the Universe
How does the universe work?
• Mapped out by science
• New questions arise
LARGELY ANSWERED BY SCIENCE.
Traditional Questions about the Universe
The ultimate fate of the universe?
• Laws of physics projected into the future
• An advanced topic
LARGELY ANSWERED BY SCIENCE.
End Part 1 – The Universe (Part 2 next week –Life and the Mind) Advanced topics available….
B: Questions about Life and Mind
A: Traditional Questions about the Universe
B: Questions about Life and Mind
D: New questions which arise from science
E: Questions about Philosophy itself
Where we are now
C: Questions about The Spiritual and Ethics
Where did the elements of life come from?
Or what is your body made from?
1. Hydrogen (H) nucleus – protons – from the quark-gluon plasma.
At Big Bang + 3 minutes
Quark-gluon plasma cooling protons
2. C, N, O nucleii
inside all stars.
200 M years to present.
3. Na, Mg, P, Cl, K, S in the first large stars, blown off in solar wind. 200 M years
4. Al, Si, Fe in a supernova (exploding star). 300 M years
Here is where they all came from
As these nucleii cooled, they collected
electrons to form neutral atoms
82
• These atoms formed gas and dust.
• They drifted around in space, until they clumped together by gravity
Enlightenment through science • The clump grows,
and a new star forms at the center
Enlightenment through science
• The surrounding disk clumps into planets
Enlightenment through science
• These elements were being modified by radioactive processes.
• They remained on earth until taken up by life.
Enlightenment through science • Meanwhile, on the new Earth, things stabilize
Enlightenment through science • Life began, when a replicating molecule arose
• (no trace left now - possibly related to RNA )
Enlightenment through science • Fish and Reptiles evolved
Enlightenment through science • Then came Mammals
Enlightenment through science • Homonids
Enlightenment through science • And eventually Homo Sapiens - intelligent
Intelligent enough to (eventually) invent science
Where does the mind fit in? A traditional view
Immaterial
realm
Material realm
94
Minds, souls, spirits
Planets, trees, humans
The car won’t start story… Your reactions illustrate that
THERE ARE NO GAPS IN HOW THE WORLD WORKS*
*At least in the here and now
Therefore:
Immaterial
realm.
Empty?
Material realm
Must include
everything,
material and
spiritual
“Spiritual” phenomena
are either:
• a layer of complexity
in the Material realm,
• Or do not exist!
96
If the universe is only material… How do we explain the Mind?
Layers of complexity:
What can science tell us?
Watch Prickles and goo Attached, or www.youtube.com/watch?v=XXi_ldNRNtM
At the fundamental level – things are pretty well sewn up – there are apparently no gaps… • At least since inflation • With some possible exceptions such as black holes • Some unidentified matter • Deeper levels of explanation might exist.
At higher levels of complexity – much is known, and much is unknown: • Eg the procrsses of life • The brain • Consciousness • An opera Lets look at some of these!
What has science told us about the brain?
Physics has shown that the brain
obeys
the Law of Conservation of
Mass
If you buy a lamb’s brain from the butcher…
What has science told us about the brain?
Physics has shown that the brain obeys
the Laws of Motion
What has science told us about the Brain?
Solving difficult mental problems burns calories!
Physics has shown that the brain obeys
the Law of Conservation of Energy.
What has science told us about the Brain?
Science has shown that the brain has
capabilities in proportion to its
size!
X-ray of Homer Simpson
What has science told us about the Brain?
The electrochemistry
is largely understood… at a fundamental
level
What has science told us about the Brain?
• THUS the brain obeys ALL the laws of physics
• Its operation is based on the four forces of nature.
What has science told us about the Mind?
The mind is what the brain does.
Your computer runs Applications
- Word, Excel, Google, printer, Skype etc.
Your brain runs your Mind
- your body, movement,
reads newspapers etc.
What has science told us about the Mind?
• Can a Mind exist, separately from a Brain?
• The fossil record…
• The record of fossil skulls shows that nature invested a lot in providing brains
• All sentient creatures possess a brain. • No sign at all of a mind without a brain. • ALL MINDS REQUIRE BRAINS!
• What happens if your brain is starved of oxygen?
• Of energy (ATP)? • You faint!
• ALL MINDS DEPEND TOTALLY
ON A PHYSICAL LIFE SUPPORT SYSTEM
• What happens if your brain is infused with alcohol?
• - Your Honour, I might have been over the 0.05% limit, but my mind is separate and was not affected.
• ALL MINDS ARE AT THE MERCY OF CHEMICALS!
Sentience - the capacity for Pleasure & Pain
(brain function)
– variation throughout a normal life
Sentience
age
birth
Conception
death
Nervous system forms © 2007 Ian Bryce
111
1
0
Sentience – the topic of a talk on Wed 14 Oct
2015, see Meetup - Open Forum Sydney
Sentience
age
birth
Conception
death
Nervous system forms © 2007 Ian Bryce
112
1
0
How does the mind interface with the world?
Inputs: senses Outputs: Motor functions
Optic nerves cross at the chiasm
How does the mind interface with the world?
The inputs and outputs can be reproduced by science
What has science told us about the Mind?
To communicate by other means • Intuition • Telepathy • Psychic abilities • Telekenesis • Prayer • Connection to an immaterial realm would require a new force in physics.
What has science told us about the Mind?
Thought
Science
Conscience
Prayer
Meditation
Admiration
Fear
Happiness
Hypnosis
Dreams
These are mental processes!
What are mental processes?
They are all internal brain functions!
They are layers of complexity – emergent properties
– of physical matter
What is known about the mind?
Fundamental level
• Prickly
• Well established
• Highly confident
Higher level of complexity
• Gooey
• A little is known
• Much to find out
• Emergent properties
Questions about Life
Where did life come from?
• Natural physical processes
• The mechanism is NOT known
THIS MYSTERY SURVIVES!
Questions about Life
Where did humans come from?
• Evolution from more primitive species
• Random mutations
• Natural selection
• Survival of the fittest
ANSWERED BY SCIENCE
Questions about Life
How does the mind work?
(a) At a fundamental level:
Electrochemical processes
Obeys ALL the laws of physics, chemistry etc
ANSWERED BY SCIENCE
Questions about Life
How does the mind work?
(b) At a higher level of complexity:
• Much is known…
• And much is not yet understood
• Research is constantly revealing more detail
• The mind emerges as higher levels of complexity.
IN PROGRESS
C: Questions about The Spiritual and Ethics
A: Traditional Questions about the Universe
B: Questions about Life and Mind
D: New questions which arise from science
E: Questions about Philosophy itself
Where we are now
C: Questions about The Spiritual and Ethics
Prayer Many people believe they can communicate with an external being, separately from our normal senses…
Prayer
• Science theory shows that such communication would require a new effect in physics. • The Car wont start example illustrates that there
are no such gaps in physics. • Science experiment shows that prayer is
ineffective (untercessory prayer, historical data, and modern tests)
• So prayer is only internal to your brain
Conscience or Prayer
Imagined god
Desire for guidance
Prayer… a conversation between two brain functions?
Conscience or Prayer
Immediate needs
Ingrained moral rules
Conscience …
a conversation between two brain functions?
The Mind and Past Lives SCIENCE HAS SHOWN: The MIND is a function of the brain. The brain develops in the a fetus and in the a child Memories are created from experiences as a child and as an adult There is no mechanism for installing the memories from a different brain.
PAST LIVES ARE OUT!
The Mind and Afterlives SCIENCE HAS SHOWN: The MIND is a function of the brain. It is entirely dependent on physical support systems. When the body dies, the mind stops.
AFTERLIVES ARE OUT!
Questions about Ethics
Is what happens in the universe predetermined (ie fatalism)?
• Everything that happens is influenced by prior events
• There is also chance involved through quantum mechanics*
• Therefore NOT determined
• “God does play dice…”
• ANSWERED!
* most likely. One theory (De Broglie–Bohm) contains QM with underlying truths, which make the universe fixed since the big bang.
Questions about the Ethics
Do we have freewill? No “Yes or No” answer.
Recast the question: We experience a feeling of freewill. What is its mechanism?
• The mind operates at a fundamental level by the four known forces
• This includes decision making
• Our choices are influenced by our genes – genetic packages from our parents
• And memes – behaviour packages from society
• And chance
Freewill is the feeling we have, while our brain performs the operation of choosing
RECAST AND ANSWERED
Questions about Ethics Freewill is the feeling we have, while our brain performs the operation of choosing
A Big Question about life:
Where do morals come
from?
“Philosophers have been
debating it for 3000 years…”
134
1. Where do morals come from?
(a) In the tribal culture
Gods
Prophets Holy books
The People
135
Material
realm
Spiritual realm
136
1. Where do morals come from?
(b) But a Problem has been revealed
by travel and communication
137
God #1
God #2
God #3
God #99
God #4
God #5
Where do morals come from?
(c) Enlightenment 1650+ Inspired by the new scientific findings
Spiritual realm
Empty?
Material realm
Everything
What possible
origin of morals
can we fit into
this?
138
1. Where do morals come from?
(d) Post-Enlightenment thinkers
reject the supernatural
look to nature
use introspection
Duty for duty’s sake - Kant
Its good to do good – Holyoake?
We hold these truths to be self-evident - Declaration of Independence
- illustrates the failure of introspection…
139
Where do morals come from?
(d) Post-Enlightenment thinkers
Spiritual realm
Material realm
People believe its good
It IS good
Moral decisions
140
Where do morals come from?
(d) Post-Enlightenment thinkers
Like a self-
licking ice
cream!
141
Where do morals come from?
(e) Modern science
Add interactions with others
One generation Next generation
Genes Packages of DNA passed from parents
Memes Packages of behaviour passed from parents and community
How
characteristics
(physical and
social) are
propagated
through time
Others in tribe
142
Material realm
Where do morals come from?
(e) Modern science (evolution and
neuroscience) says:
One generation Next generation
Genes Packages of DNA passed from parents
Memes Packages of behaviour passed from parents and community
How
characteristics
(physical and
social) are
propagated
through time
This behaviour can be described as “built-in”, instinct, or intuition
143
Material realm
Where do morals come from?
Modern science has answered that.
Briefly: Evolution! Which means:
Variation plus survival of the fittest
© C. Darwin ~1850
• Applies to physical
characteristics and also
behaviour
• For humans and other
animals
144
Questions about Ethics
Where do morals come from?
A: Instinctive morality – from evolution
• Brain functions
• Genes (selfish and altruistic)
• Memes
• Developed by groups of animals and humans
• Have survival value
• Evolving
• No gods or holy books
Questions about Ethics
Instinctive Morality - Continued
• No absolute systems of morals
• Can’t say “I’m right and you’re wrong”
• Some people and groups have morals we would regard as poor
• Examples?
• William on Struggle Street (SBS) – a very simple morality – “You got it, I take it.”
ANSWERED
A new source of morality
Humans now* have a
very active prefrontal
cortex * Homo Sapiens 200,000 years
• Allows detailed
reasoning
• Has provided
scientific knowledge
• Allows enhanced
moral decisions 147
An example of a morality
invented by humans
“Welfare of sentient beings”
Four words*
Rationale: Most common threads in moral
systems include the “golden rule” and concern
for others Why? Because they are aware, or conscious, and capable of experiencing pleasure and pain Their welfare is important to us. *This is the topic of a separate talk.
148
Where do morals come from?
(e) Modern science:
Now add a new source of behaviour
One generation Next generation
Genes Packages of DNA passed from parents
Memes Packages of behaviour passed from parents and community
How
characteristics
(physical and
social) are
propagated
through time
Scientific knowledge and analysis
Others in tribe
149
Questions about Ethics (continued)
Where do morals come from?
B: Reason
• Brain functions
• Neocortex
• We are free to make up our own morals
• But we must live with the consequences!
ANSWERED
Questions about Ethics
What are human rights?
• Arise through human NEEDS
• Physical needs include food, water, clothing, shelter, safety
• Psychological needs include freedom from oppression, forming relationships, setting goals
• If we respect other peoples feelings, we will recognise these rights
• ANSWERED!
Questions about Ethics
What about animal rights?
• Animals also have needs
• Physical needs include food, water, shelter, safety
• Psychological needs include freedom from oppression, forming relationships, (less than humans)
• Animals generally have less sentience (capacity for pleasure and pain)
• So animals should have rights to suit their needs
• ANSWERED!
These slides may be downloaded from
http://www.meetup.com/Secular-Party-NSW/files/
Or email me [email protected]
New questions which arise
from science
Advanced Topics
A: Traditional Questions about the Universe
B: Questions about Life and Mind
D: New questions which arise from science
E: Questions about Philosophy itself
Where we are now
C: Questions about The Spiritual and Ethics
• Elliptical vs circular and hyperbolic orbits
• The ultimate structure of reality?
• Evolution of the universe since the big bang?
• Dark Matter?
• New Horizons Mission to Pluto
• Does it have an edge and is it infinite?
• Is the universe curved?
• The eventual fate of the universe?
• The source of the big bang?
• Higher levels of brain function?
Some of these are answered in Advanced Topics
Some are addressed in other presentations.
New questions which arise from science (advanced topics)
How is science addressing these questions?
What are the best answers? We will now examine some
examples.
Elliptical vs circular
and hyperbolic orbits
Solve Newton’s equation of motion for a central gravitational force:
Conic Sections
The ultimate structure of reality? • Might there be a new force in physics?
• The search for the Higgs Boson – LHC – largest machine ever built
• Found a new particle, implying a new force field
• Does not interact with matter, under current conditions
• So cannot account for freewill, psychic phenomena etc.
Evolution of the universe since the
big bang?
The tools being used: • Telescopes (optical radio, IR) • Particle accelerators • Theory • Simulations
Dark matter?
• There is too much gravity in galaxies, therefore dark matter
• Gravitational lensing can map it • The hunt is on to identify it!
How is the solar system being explored?
New Horizons mission to Pluto
New Horizons
space probe to
Pluto
New Horizons space probe to Pluto
Note RTG on New Horizons. Why?
Does the universe have an edge?
Could there conceivably be a boundary where stars and galaxies stop?
Does the universe have an edge?
• This is simple. Astronomy has clearly established the Cosmological Principle:
• The universe is Homogeneous – same rules apply everywhere, and matter is uniform (on large scales)
• The universe is Isotropic – behaves the same in all directions
• If there was an edge, the laws and matter would be different there.
• The edge hypothesis is REJECTED.
Is the universe curved?
In Euclidean geometry (like a sheet of paper), parallel lines remain the same distance apart. But there are other possibilities. In our 3D universe, general relativity specifies the curvature of space:
General Relativity: Space is curved by
the presence of matter and energy…
On larger scales, with many objects, the curvature averages out…
Finally, as matter becomes uniform (a fluid), the curvature must
become uniform too. The causes of curvature (sources) are: • The total density (visible matter,
dark matter, and energy) • Possible dark energy (or cosmological
constant) • Any expansion rate (Hubble Constant)
Curvature?
This is the first Friedman equation. It gives the curvature constant k for an evolving universe (at each moment), in terms of the state of the universe.
Curvature?
The inputs are the physical parameters at a given moment in time: • The average density of matter (including galaxies and
the gaps between them) (both visible and dark matter)= 5 protons per cubic metre
• The Hubble constant (recession velocity per distance away, approx 1 / 14 billion years)
• Gravitational constant (accurately known) • The cosmological constant (dark energy or a basic
property of spacetime). • There are 3 possibilities for the curvature:
Is the universe curved?
R = infinity: critical, Euclidean geometry, universe has no edge, infinite number of galaxies.
R < 0: open, hyperbolic space, universe has no edge. Parallel lines double their spacing in distance π/2 |R|. Infinite number of galaxies.
R > 0: circumference of a circle is smaller than Euclidean. Finite number of galaxies, but still no edge. Parallel lines meet at a distance π/2 R. If you travel in any direction, in principle you will return home! After travelling a distance 2 π R.
Is the universe curved?
A. Direct measurement of the curvature
• Number of galaxies near and far • Size of galaxies near and far. These measures are only approximate, due to the reducing brightness and increasing age of distant objects. These suggest any curvature is small (<0.3) within the observable universe. i.e. |R| > 40 billion light years. You need not fear parallel lines meeting on your exam paper!
Cosmic Microwave Background (CMB) • Spectrum = black body. • Strength = 2.7K. • Ripples magnitude = 10-5 of average. • Ripples spectrum = ~ 1 degree.
Is the universe curved?
Introduce one tool:
Is the universe curved?
B. Indirect evidence for curvature (induction). • The CMB can be compared with the current
distribution of galaxies – suggests approximately flat. • Theories of the evolution of the cosmos, can correct
for the differences in age of bodies. • The Friedman equations – link curvature to matter
density and expansion. • Inflation theory – prefers a flat universe. Results - unclear to date.
What is the ultimate fate of the universe?
The main tools: • a simulation of the universe • combined with detailed observations of
redshifts.
The ultimate Fate of the universe?
• Friedmann equations – derived from general relativity assuming uniform matter distribution:
These yield the time evolution and geometry of the universe, given the three types of density, at any given reference epoch (usually the present). The second equation introduces pressure (like a gas). http://en.wikipedia.org/wiki/Friedmann_equations
The ultimate Fate of the universe?
The variables #1 are (for reference): a is the scale factor – the distance from Perseus cluster to Hydra cluster (for example), measured at a given time, compared to what it is NOW. Growing steadily. å is its rate of change, hence the expansion rate, at a given time. k is the curvature (unitless). c is the speed of light (constant).
The ultimate Fate of the universe?
The variables #2 are (for reference): ä is the acceleration (+ or -) in the expansion rate, and is the output of equation 2 (the dependent variable). G is the gravitational constant (really constant) ρ is the average density of matter and energy ~ 5 protons per cubic metre, whose gravity slows the acceleration ä p is the pressure of matter and radiation Λ is the Cosmological Constant, or Dark Energy density
What role does Dark
Energy play? It wins in the end, pushing the universe
apart, as gravity
weakens.
The ultimate Fate of the universe?
• Some of the variables can be observed directly. • Others are adjusted so that when the simulation
is run, the predictions best match real observations.
• The result is a universe which is not only expanding, but accelerating!
• Confident but not certain. Brian Schmidt, 2011 Nobel Prize in Physics
The ultimate Fate of the universe?
The ultimate Fate of the universe?
• Thus the universe will never collapse, but will go on expanding forever.
• Eventually the stars will exhaust their fuel, and everything will cool down – a heat death.
• Galaxy clusters will retain their size, but their separation will increase until others become invisible. If future astronomers exist then…
• They will think there are 54 galaxies in the universe (the current Local Group).
Or that is one scenario.
The ultimate Fate of the universe?
Map of the universe seen from the Milky Way in the year 1,000,000,000,000,000 (simplified)
A timeline of our ultimate fate
-13.8 B y: big bang
-4.6 B y: sun, planets
-3.3 B y: bombardment stopped
-3.1 B y: life started
-0.0002: our species
0: now
1 B y: sun gets too hot, we move?
4 B y: Milky Way collides with Andromeda
100 B y: other galaxy clusters recede, most stars get cold
100 Trillion years: other galaxy clusters have gone
196
Before the Big Bang
Before the Big Bang
Before the Big Bang
A survey of hypotheses And the scant evidence.
Before the Big Bang
Inflationary Multiverse Prof Max Tegmark, MIT Inflation is continuously spawning universes. Prof Anthony Aguirre, UCal Bubbles form, spawn U’s with different properties, different laws, different forces, different no. dimensions, different physics classes.
At bottom right – inflation
continuously spawning new
universes!
Before the Big Bang
Bump from next universe Prof Laura Mersini-Houghton - U N. Carolina String theory and QM. Wave Function of the universe is travelling over the landscape of quantum fluctuations. Some energy got trapped in a well. Inflated to become our universe. Other energy got trapped on other wells, became other universes. Different sizes, different properties? This hypothesis predicts, that where two universes were being spawned nearby, the gravitational pull disturbed the uniform matter, causing dark spots 10 degrees wide in CMB. Observed – next slide.
Before the Big Bang
Cosmic Microwave Background. Spectrum = black body. Strength = 2.7K. Ripples magnitude = 10-5 of average. Ripples spectrum = ~ 1 degree.
Before the Big Bang
Infinite patchwork multiverse Prof Max Tegmark, MIT • Our (visible) universe 10^80 particles, so there are
a finite no of arrangements. • But if infinite universes, then must be others the
same as ours! • An identical You must be in another. • And also variations of you, dressed differently,
married differently… • Laws the same, different history classes.
Before the Big Bang
Hilbert Space or Forking paths. Prof Seth Lloyd, MIT. Always laughing. • If I toss a coin, the universe splits into two copies. • They never recombine. • There have been ~10^120 decisions so far in this
universe. So there must be ~2^10^120 possible universes.
This hypothesis does not seem to make any testable predictions.
Before the Big Bang
Many Worlds interpretation of Quantum Mechanics Eg electron in double slit experiment. The electron seems to pass through both slits, so it can superimpose at the screen…
Before the Big Bang
The world splits. In A, the electron goes through slit 1. In B, it passes through slit 2. When measurement occurs, worlds A and B recombine, providing the required superposition. Nothing testable here – just an interpretation of conventional quantum mechanics.
Before the Big Bang
Chain of universes. Universes give rise to similar progeny. • When a black hole forms in our universe, the density and
temperature go to infinity. This is called a singularity. • The laws of physics break down, and must change into
different laws…
Before the Big Bang
…Chain of universes. This could conceivably spawn a new big bang, with its separate spacetime. Prof Robert Mann, Perimeter Institute Has a variation on this idea, where black holes in 4 dimensional universes generate a 3 D event horizon,, which became our universe.
So be careful when pulling the bath plug! Who knows where you might end up?
Before the Big Bang
Lava lamp hypothesis as a universe generator My own concept - Ian Bryce
Before the Big Bang
Lava lamp hypothesis as a universe generator #1 My reasoning goes like this: • Something (call it the motherverse) caused the Big
Bang and hence spawned our universe. • Our universe (with its known spacetime and state
laws) is not observed to spawn new universes*. Therefore, the motherverse must have (or have had) different laws of physics. Call them Federal laws.
*Possible exception: when a black hole collapses.
Before the Big Bang
Lava lamp hypothesis as a universe generator #2 • If we try to retrace our timeline, we come to a
stop* at the BB. Our space and time is not connected to anything else.
• Therefore, the motherverse had a different type of time.
• The anthropic principle suggests that there are many universes, with different physical constants.
• Therefore we need a universe generator which continuously spawns daughter universes, with differences. Possibly chaotic.
*Time becomes imaginary, according to some.
Before the Big Bang
Lava lamp hypothesis as a universe generator #3 • Ockhams Razor suggests that a
motherverse with simple properties is more likely than one with complex properties.
• I have a device which seems to demonstrate many of these properties.
• Lava lamp!
Before the Big Bang
Lava lamp hypothesis as a universe generator How does it fit the desired universe generator? #1 • Continuously spawns bubbles of wax - new
universes. • The bubbles are varying diameters, which
would cause different surface tension. • This would vary the apparent constants of
physics in the different bubbles • If they were universes, this variation might
allow life in at least some.
Before the Big Bang
Lava lamp hypothesis as a universe generator How does it fit the desired universe generator? #2 • Retracing the timeline of a ball of lava, leads to a time
when it was melting – different laws – and then was solid – time stops.
• Retracing the timeline of our universe, leads to the inflation period when the laws were different, and then time stops.
• The static solid wax (motherverse) has very simple laws, compared to the liquid bubbles where lots can happen - emergent properties
• This idea could direct the search for a hypothetical precursor to the Big Bang.
Testing before the Big Bang
How can a hypothesis about before the big bang be tested? We can’t see back past the BB directly. • But any hypothesised motherverse must have given rise to
our universe, with the laws and constants we have now.
• Its predictions can be tested against surviving evidence: • The cosmic microwave background temperature • The spectrum and distribution of ripples in the CMB • The distribution of matter • Possibly gravity waves from the very early universe.
So hypotheses can be tested (to some extent) by induction!
Possible gravity waves from an extreme current event (binary pulsar).
Possible gravity waves from an extreme early event (quantum fluctuations in inflation).
Summary: We have seen many ideas of what happened
before the Big Bang. I have put forward some ideas of my
own.
Higher levels of brain function?
Being investigated by:
• Optogenetics – make neurons fire when illuminated
• Fine imaging – trace the individual neurons
• Functional imaging – while a live brain in thinking
Higher levels of brain function?
The location of most functions has been identified
The Material vs the Spiritual
Are religion and science compatible beliefs? Some statistics I have found.
The Material vs the Spiritual #1 Worldwide, there is a clear decrease in belief with level of education.
Of course, in many countries, even scientists would not dare to report their disbelief. So the real case must be even stronger…
The Material vs the Spiritual #2 In the USA, where there is greater freedom of speech,
the reported non-belief increases very dramatically with education in science.
The Material vs the Spiritual #3 Over the last century, belief in a god has almost
vanished among the top scientists.
The Material vs the Spiritual continued
• So science and religion are clearly not compatible.
• The more one learns about the real world, the less one can believe in a god.
• Reliable information usually comes from experts, and those who know about the universe, know there aren’t any gods.
Questions about philosophy itself
A: Traditional Questions about the Universe
B: Questions about Life and Mind
D: New questions which arise from science
E: Questions about Philosophy itself
Where we are now
C: Questions about The Spiritual and Ethics
Questions about philosophy itself: Logic and reasoning
Logic and reasoning
Two types: 1.Deductive 2.Inductive
1. Deductive Reasoning
Classical philosophy: Plato said: • All men are mortal (a general premise) • Socrates is a man (a specific premise) • Therefore Socrates is mortal (the conclusion)
Premise 2
Premise 1
conclusion reasoning
Premises Or axioms Or propositions Or assumptions Or Postulates
1. Deductive Reasoning
Classical philosophy: Plato said: • All men are mortal (a general premise) • Socrates is a man (a specific premise) • Therefore Socrates is mortal (the conclusion)
Premise 2
Premise 1
conclusion reasoning
This case is valid. What can go wrong?
Premise 2
Premise 1
conclusion reasoning
1. Deductive Reasoning
Classical philosophy: • All dogs have 4 legs • Socrates is a dog • Therefore Socrates has 4 legs
Premise 2
Premise 1
conclusion reasoning
Deductive logic is used to justify religions
1. Deductive Reasoning
How does deductive logic relate to the real world?
It is only as strong as the assumptions.
Premise 2
Premise 1
conclusion reasoning
1. Deductive Reasoning If there are no aardvarks in the premises,
There can be no aardvarks on the conclusions.
Premise 2
Premise 1
conclusion reasoning
1. Deductive Reasoning Likewise, if there are no gods in the assumptions,
there can be no gods in the conclusions.
Premise 2
Premise 1
conclusion reasoning
No gods have ever been observed in the real world.
And they cannot just pop out of the reasoning.
This does away with the classical philosophers’ arguments for the existence of god: • Ontological Argument • First Cause • Argument from design
Deductive logic provides many tools for science
• Number theory • Algebra • Geometry • Set theory • Groups theory • Statistics
Deduction always starts from axioms. The question remains: are these axioms true in the real world? For general rules, this can never be “proved”… so science must turn to ...
2. Inductive logic
2. Inductive logic Classical examples:
All swans we have seen are white. Therefore all swans are white. Not true.
All ravens we have seen are black. Therefore all ravens are black. Probably true.
Induction in science
observations
Creative step
Make predictions (specific)
test
Form hypothesis (general)
Discard or
revise
fail
survives
pass
Make more predictions
test
Hypothetical deduction
Falsifiability
A good theory must be testable, ie make predictions which can fail. It must actually be tested. It must pass. Every time it survives a test, it gets stronger.
Karl Popper 1934: My proposal is based upon an asymmetry between verifiability and falsifiability; an asymmetry which results from the logical form of universal statements. For these are never derivable from singular statements, but can be contradicted by singular statements.
Bayesian Inference
H = hypothesis
E = evidence
Provides a theoretical basis for Popper’s falsifiability criterion.
Example from science Galileo dropping balls
from the Leaning Tower of Pisa
Try to form a hypothesis: 1. Deduction Everything I dropped has fallen to the earth (specific cases) Therefore, form the hypothesis: every object that is released, falls downward (a general rule). Not valid. But a god start.
Example from science Galileo dropping balls
from the Leaning Tower of Pisa
2. Induction Form the hypothesis: every object that is released, falls downward (a general rule). Predict: Stones will fall Test: Confirmed. Predict: Apples will fall. Test: Confirmed. Predict: Cannon balls will fall. Test: Confirmed. GETS STRONGER EVERY TIME
Example from science Galileo dropping balls
from the Leaning Tower of Pisa
2. Induction Until… Drop a helium balloon Falls upwards! FALSIFIED. Modify the hypothesis: All heavier-than-air objects fall downwards when released. PASSES ALL TESTS. Making it a stronger hypothesis. (or does it pass all tests?)
Example from the courtroom • INDUCTION • She went into the room • You went into the room • You came out carrying a
bloody knife • Therefore, beyond a
reasonable doubt, you are guilty
• CIRCUMSTANTIAL EVIDENCE.
• DEDUCTION • The witness saw you
stick a knife into the victim
• Therefore you are certainly guilty
• Valid – in a specific case only.
Summary on reasoning
• DEDUCTION
• Premises, reasoning, conclusion
• Appears to offer certainty
• Does not make predictions (general rules) about the real world
• Only as good as the premises.
• INDUCTION
• Hypothesis, predict, test
• Each time tested it gets stronger
• Can tell us about the real world
• Never offers certainty
• Offers confidence – more valuable.
Finis!
To continue the quest
• Australian Skeptics www,skeptics.com.au
• Humanist Society of NSW www.hsnsw.asn.au
• WEA lectures
• Sydney Uni Centre for Continuing Education
• Read New Scientist, Scientific American
• Lectures by scientists eg Sydney Science Forum