Humanity and Science in Perspective

CC105Prof. Jackson

Today’s Music“The Universe Song” Monty Python

Today’s Lecture• The story of everything• Math in Nature• The cosmic size-scale• The cosmic time-scale• Science and truth• Humans• The future

What is Science?“Science is the marriage of

skepticism and wonder.”

Carl Sagan

The Story of Everything• In the beginning…Big Bang, and there

was light.• Primordial soup spawns particles, and

eventually hydrogen and helium.• Stars form from the hydrogen/helium

gas.• Stars make heavy elements and explode.• More stars form, enriched with heavy

elements.• The Sun forms• The Earth forms as a byproduct• Chemistry on earth spawns life• Humans evolve from ancient ancestors.

“It is Nature herself, and not the mathematician, who brings mathematics into natural philosophy.”

Kant

Math in Nature• Does math form the fundamental

basis for everything?• Math revealed in nature

– LAWS– FORMS

SymmetryIn mathematics, “symmetry’’ refers to an operation that leaves an object unchanged.

Reflect through a mirror

Rotate by 90o

Crystals

Ice: hexagonal symmetry

Ice

Edward

Weston

What about life?• Many creatures have mathematical

shapes• Many creatures exhibit symmetries

– Bilateral– Rotational

Mathematical Forms in Life

Equiangular Spiral

0/0eRR

Edward WestonThe Chambered Nautilus

Nautilus Shell

A perfect logarithmic spiral!

More Equiangular Spirals

More spirals

Bilateral Symmetry

Bilaterally Symmetric Life

Bilaterally Symmetric Life

Edward Weston

Bilaterally Symmetric Life

Edward Weston

Bilaterally Symmetric Life

Edward Weston

Rotational Symmetry

Rotationally Symmetric Life

Rotationally Symmetric Life

Rotationally Symmetric Life

Rotationally Symmetric Life

Rotationally Symmetric Life

Mushroom Gills

MushroomsGill

spacing never

too large

Fractals in nature• Fractals are objects that look the

same regardless of the magnification.

• “Scale-invariant”

Fractals

River drainage

More fractals

More fractals

More fractals

More fractals

Fractal Life

Fractal Life

Fractal Life

Fractal Life

Fractal Life

Fractal Life

Examples of fractals in nature• Trees• Lungs• Viscous fingers (fluid flow)• Rain clouds• Electrical discharges• Shorelines

Fractals in music: Music is pink noise

Ampl

itude

Frequency

White noiseAf

Pink noiseAf-1

Brown noiseAf-2

Mathematics is relevantIt is everywhere, and part of

everything, both inanimate and animate.

The Cosmic Perspective• Where do humans fit in?• Size• Time

The Cosmic Size ScaleMovie: Powers of Ten

The Cosmic Time Scale• The Universe began about 14

billion years ago.• The solar system formed about 5

billion years ago.• Life appeared 3 billion years ago.• Homo sapiens appeared 100,000

years ago.

The Cosmic Time Line

15 billion yr 10 billion yr 5 billion yr today

Universe begins Solar system forms

5 billion yr 4 billion yr 3 billion yr 2 billion yr 1 billion yr

Earth forms Life begins Trilobites

today

The Cosmic Time Line

15 billion yr 10 billion yr 5 billion yr today

Universe begins Solar system forms

500 million yr 300 million yr 100 million yr

Trilobites Fishes Amphibians Reptiles Mammals Hominids

If Eternity Were A Year: Compress 14 billion years into oneSun forms: Late AugustEarth forms: September 1Life begins: Late SeptemberLand animals: December 20Dinosaurs: December 29Hominids: 10:00 pm, December 31Homo sapiens: 11:53 pm December 31

“It is more important to have beauty in one’s equations than to have them fit experiments.”

Paul Dirac

Science and beauty• Why does aesthetics play such an

important role in science?• Perhaps our notions of “beauty”

reflect a concordance with the underlying mathematical structure of Nature.

• Is beauty truth? Or is truth beautiful?

The Faith behind Science• The Universe is built on a foundation

of order.• The Universe is explicable.• The Universe is mathematical.• Nature operates with a few simple

laws.• These laws have the same rules

everywhere.

Science and truthScience is only as good as its

predictions!Important to distinguish between the

ideas and the predictions.Science provides a quantitative

description of Nature.Can only describe reality within the

limits of the human mind.Science may never arrive at truth.

And yet…Some ideas work so well they seem

indistinguishable from truth:– Atoms– Gravity

Why does it work?• Empiricism: go to Nature for

answers• Reject bad theories.

“The great tragedy of Nature is the murder of beautiful theories by ugly fact.” Mark Twain

Questions science cannot (yet) answer• Is there existence after death?• What is reality?• Why is there something rather

than nothing?• What defines good and evil?

Science and religion and philosophyScience seems to be encroaching on

themes formerly addressed by philosophy and religion

• Creation• The nature of reality• The origin of humans• Our place in the Cosmos• The mind

Where Do Humans fit it?The Copernican Principle

Humans do not occupy any special place in the Universe.

We inhabit• An ordinary planet• Orbiting an ordinary star• In the backwaters of the Milky Way• An ordinary galaxy• In an ordinary group of galaxies• In an ordinary super-cluster of

galaxies

Are we insignificant?• Individually, perhaps• BUT… will humans colonize the stars?• Will we exploit the Galaxy’s

resources?• The role of the observer in quantum

mechanics• Does human thought collapse the

wave function?• We are part of the strange loop of

Nature.

The Future• We face a catastrophe (war,

plague, starvation).• We learn to live in harmony with

our planet.• We move into space and colonize

the Galaxy.

Are humans alone?• Nothing particularly special about

Earth• Life may well exist on other planets• If their civilization got a head start,

they may well have already colonized the Milky Way

• If so, where are they?• We are looking!

Why are you here?• Science is a key part of society.• Stimulates technology.• Provides the crucial knowledge for

social and ethical decisions.• Humans are a curious species, and

science provides answers.

Scientific Social Issues• Extermination of species• Organ transplants• Cloning• Nuclear power and weapons• Overpopulation• Use of outer space• Global warming• Ozone depletion

Where do you find science?

Just open your eyes, and look around.