humanity and science in perspective cc105 prof. jackson

Humanity and Science in Perspective

CC105

Prof. 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

Mushrooms

Gill 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

Am

plit

ude

Frequency

White noiseAf

Pink noiseAf-1

Brown noiseAf-2

Mathematics is relevant

It is everywhere, and part of everything, both inanimate and animate.

The Cosmic Perspective

• Where do humans fit in?• Size• Time

The Cosmic Size Scale

Movie: 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 one

Sun 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 truth

Science 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 philosophy

Science 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 PrincipleHumans 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.