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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 Symmetry In 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 R R 0e The Chambered Nautilus Edward Weston 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 Amplitude Fractals in music: Music is pink noise Frequency White noise Af Pink noise Af-1 Brown noise Af-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 Universe begins Solar system forms 15 billion yr Earth forms 5 billion yr 10 billion yr Life begins 4 billion yr 3 billion yr today 5 billion yr Trilobites 2 billion yr 1 billion yr today The Cosmic Time Line Universe begins 15 billion yr Trilobites 500 million yr Solar system forms 10 billion yr Fishes Amphibians 300 million yr 5 billion yr Reptiles today Mammals Hominids 100 million yr If Eternity Were A Year: Compress 14 billion years into one Sun forms: Late August Earth forms: September 1 Life begins: Late September Land animals: December 20 Dinosaurs: December 29 Hominids: 10:00 pm, December 31 Homo 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 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.
