1 / 112

Theories of Everything

Theories of Everything. John Ensworth, M.S. NASA’s Sr. Science Education Specialist.

grover
Télécharger la présentation

Theories of Everything

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Theories of Everything John Ensworth, M.S. NASA’s Sr. Science Education Specialist

  2. “If we do discover a complete theory, it should be in time understandable in broad principle by everyone . . . . Then we shall all, philosophers, scientists, and just ordinary people be able to take part in the discussion of why we and the universe exist.” - Stephen Hawking

  3. “No matter how hard you try to teach your cat general relativity, you're going to fail.” - Brian Greene

  4. “We can certainly go further than cats, but why should it be that our brains are somehow so suited to the universe that our brains will be able to understand the deepest workings?” - Brian Greene

  5. We seem wired to make sense of the world around us… • Our brains learn by linking previous ideas to new ideas. • We make categories of everything… • Is each green thing growing outside its own entity? – trillions of things • Trees, bushes, grass, moss – 400,000 kinds • Or better: Chlorophyll – 6 related kinds

  6. Myths vs. Science • Myths try to have an all-encompassing explanatory power – they have breadth • Science tries to create explanations that have both breadth and depth • Breadth = link many phenomena at once • Depth = explanation and prediction accessible to independent observers

  7. Creation Myths • The first Theories of Everything • Myth seems to now mean ‘untrue’ now. • More properly: a traditional story accepted as history; serves to explain the world view of a people – sometimes including its origin.

  8. It exists! • We seem to be wired to expect there is a reason behind everything that happens… • Cause and Effect!

  9. A quasi-scientificstart… • Pre-Copernican Astronomy Astrology/Astronomical Observations • Babylonians, Chinese, Arabia Region • Aristotle 384 to 322 B.C. in Greece • His work persisted for almost 2000 years • Created a Philosophy not science • Assumptions • The Earth was changeable and imperfect, the heavens were perfect and unchangeable • Crystalline spheres • No parallax • Bowl shaped sky

  10. Forces • We know of four forces that weren’t even imagined back then… • Gravity, Electromagnetism, The Strong and the Weak Nuclear forces • We’ll show more detail on Gravity – then sweep through the other 3 on our way to UNIFICATION.

  11. GravityLinking the Heavens • Copernicus 1473-1593 • Long church affiliation • Uncle was an important bishop in Poland • Lived in quarters adjoining the cathedral in Frauenburg • Heliocentric model (sun central model) • De RevolutionibusFinished in 1530 • Explained planetary motions without epicycles • BUT didn’t predict the motions well – still • “Perfection” still expected • Circular orbits modeled, real orbits ellipses • He had to add small epicycles to fix it

  12. GravityLinking the Heavens Post-Copernican Astronomy Tycho Brahe 1543-1601 • Measured positions of planets in the sky • 1572 a “new star” appeared (Tycho’s supernova) • Measured the parallax of the nova- no parallax! • Broke the ‘perfect universe’ assumption • He saw no parallax in the stars – concluded Copernican model poor • Without telescope measured 777 star positions • Planetary positions daily for 20 years • Hired Mathematicians to work out the orbit = Kepler

  13. GravityLinking the Heavens • Johannes Kepler (1571-1630) Poor beginning • Mystical Almanac (five solids = six planets) • Illegally kept Tycho’s books • 1609 the book Astronomia Nova (New Astronomy) • Planets move faster when nearer the sun • Laws of planetary motion • Very close to stating the law of mutual gravitation (Newton later)

  14. GravityLinking the Heavens • Kepler’s Three Laws • Ellipse solved the motion problems LAW 1 • Foci • Semimajor axis, a • Eccentricity, e (foci dist/longest diameter) • Equal Area in Equal Time LAW 2 • P2(years)=a3(AU) LAW 3 • BUT he didn’t know why the planets moved

  15. GravityLinking the Heavens • Isaac Newton (1642-1727) • Discoveries • Studied optics • Developed the Three Laws of Motion • Expressed the Nature of Gravity • Invented Differential Calculus

  16. GravityLinking the Heavens • Newton’s Three Laws • A body (mass) continues at rest or in uniform motion unless acted upon by an outside force • A body’s change of motion is proportional to the force acting on it and is in the direction of the force F=ma • When one body exerts a force on a second body, the second body exerts an equal and opposite force back on it.

  17. GravityLinking the Heavens • Newton’s Law of Gravity (1687) • Greater speed results in eventual orbit; orbital speed = speed needed to move sideways fast enough to fall around the body rather than into it.

  18. 1758 A failed early try • Roger Boscovich • Asked why doesn’t everything collapse? • Fuller theory of ‘gravity’ • Above line=repulse • Below line=attract • Acts like gravityfar away.

  19. The ‘other’ forces • Electricity – Static electricity 600 B.C. (Greeks), Chinese 270 B.C. Electric eels, 1752 Benjamin Franklin’s kite idea • Magnetism –, Greek writings around 500 B.C., Chinese compasses ~ 100 A.D. • James Clerk Maxwell 1831-1879 unified them into one theory: Electromagnetism (1873) – one force – photon carries the force

  20. Gravity! Boscovich Electromagnetism 1873

  21. GravityLinking the Heavens • Albert Einstein (1879-1955) • As a teenager wondered what light would look like if you tried to catch up with it • Mass-Energy Relationship E=mc2 • Only used simple geometry and algebra! • Special Relativity time slows, space shrinks at high velocity • General Relativity time slows, space shrinks high gravity time and space warp with gravity • Worked on unifying Electromagnetism and General Relativity until the day he died.

  22. Enter more ‘other forces’ • Greek philosophers created the atom concept • Atoms first detected late 1700’s thru 1800’s • 1905 Einstein and Brownian motion • Nucleus of the atom 1909 • 1913 Bohr model of the atom • Quantum Physics model of theatom 1924

  23. The Quantum World • The Weak Nuclear force 1965 • Suspected in the 1930’s • Most visible effect = radioactivity • W and Z Boson are the force particles (like photos are for the E-M force) • The Strong Nuclear force 1975 • Suspected in the late 1920’s • Could still make nuclear weapons and power plants • Holds Protons and Neutrons together in nucleus • Gluon is the force particle

  24. The Quantum World • Einstein didn’t accept the theory of Quantum Physics that started appearing in the 1920’s • He was missing ½ of the now known forces • So though he was working literally in his dying bed on a notepad in 1955 – he didn’t have a chance.

  25. More Unification • Electroweak theory = Linked the Electromagnetic force and the Weak force • 1974 • Hey- this is really modern!! • Standard Model of Quantum Physics 1975ish • Grand Unification Theory (GUT’s) • Will link Electroweak force to Strong force • Still in progress in 2011 • CERN…

  26. CERN – Large hadron collider High-energy proton beams Opposite directions Huge energy of collision E = mc2 Create short-lived particles Detection and measurement No black holes

  27. How does the LHC work? • E = 14 TeV • λ =1 x 10-19 m • Ultra high vacuum • Low temp: 1.6 K LEP tunnel: 27 km (16.77miles) Superconducting magnets

  28. What the LHC is for? 1. Exotic particles including the Higgs Particle (or God particle)why particles with mass have mass 2. Unification of forces  ! 3. Nature of dark matter? neutralinos? 4. Matter/antimatter asymmetry? LHCb High E = photo of early U

  29. Unification of the Fundamental Forces Electricity 1864-1873 Magnetism Electromagnetism 1971 Light Electroweak Interaction Beta-decay 1976 Weak Interaction Neutrinos Standard Model ofQuantum Mechanics 1965 Protons 1973 Neutrons Strong Interaction ? Pions, etc. 1687 1916 Earth Gravity Universal Gravity General Relativity Celestial Mech. Spacetime Geom.

  30. ? ? ? ?

  31. What is a good Theory of Everything? • Will it unify the forces? • Will it explain the origin and end of the universe? • Will it explain life on Earth? • Will it explain why we are here? • Will it explain why you had eggs and toast this morning for breakfast?

  32. So is that it? • We find the Higgs Particle and we’re done? • NO!

  33. So is that it? • There are two deep problems: • Gravity is fantastically WEAK compared to the other 3 forces  1040 compared to strong force • The two most successful theories of how the universe works – General Relativity (gravity) and Quantum Mechanics (the other three) DON’T GET ALONG!! Things go to zero that you don’t want them to and things blow up to infinity when you don’t want them to.

  34. Universal GeometryFrom GeneralRelativityFantasticallySuccessfulTheory • Finite but unbounded – like a GLOBE = old favorite OUT • Infinite and unbounded – like a piece of paper – going on forever IN

  35. NASA/WMAP Science Team WMAP map The universe's baby picture about 380,000 years old Average temp = 2.725K (-455F) – Red = 0.0002 degrees warmer than the blue areas)

  36. Quantum Mechanics • Fantastically successful theory for the very small! • All modern technology based on it for example • Predicted particles that weren’t observed for decades in some instances.

  37. How the universe looks today – actual ‘nearby’ galaxies

  38. What WMAP seesWhat we see NASA/WMAP Science Team The Big Banglinks General Relativity and theother three forcesas do Black Holes DANGER!

  39. Black Hole Primer: • A region in space where so much matter is crowded that the escape velocity is at or greater than the speed of light.

  40. What else does a GUT help? • Einstein's General Relativity and Quantum Mechanicsin Black Holes • The singularity is the problem (infinity and zero together)

  41. Before String Theory (theory of everything candidate) • General Relativity + Quantum Mechanics • As you zoom down and zoom down into reality – to sizes far below that of a proton or even one of the three quarks that make up a proton – space and time get foamy. • It is bizarre and there is not good space OR time and singlarities come and go quickly all the time

  42. A T.O.E. = Strings • Superstring theory • Four forces • Strong = Gluon • Electromagnetic = Photon • Weak = Weak gauge boson • Gravity = Graviton • 3 Families of 4 particles each • Electron, Electron neutrino, Up-quark, Down-quark • Muon, Muon neutrino, Charm Quark, Strange Quark • Tau, Tau neutrino, Top Quark, Bottom Quark

  43. Grand Unification II • No room in the inn • Strings make properties of the particles via their vibrations, but not enough room in 3 or 4 dimensions • More dimensions allow us to link the forces • 10 needed (3 space, 1 time, 6 curled up space) to go to gravity • Curled up below the sub-atomic scale Calabi-Yau Shapes = 10,000’s which one?

  44. Curled up higher dimensions • All these force particles and particles are made up of strings : 10 dimensions curled up • And this solves the infinities at the smallest scales… Relativity and Quantum Mechanics can merge

  45. No more infinities/singularities calm violent

  46. M-Theory • The attempt to unify everything has lead down five roads so far… • M-Theory – adds 1 more dimension = 11 • Add one more dimension and you have a linking of the major theories! NOT FINISHED YET! 10-20 or 100 years??? • The blind men and the elephant…

  47. A nod to branes • Recent work (2003+) has now bounded the higher dimensions by membranes (branes) that. • p-branes (fill in your own # of dimensions for “p”) • We might be in a 4-D universe(3 space + 1 time) that is next to another4-D universe separated by a 5th dimension • The other 4-D universe is a ‘shadow’ universe where gravity is rooted • The theory we get from this IF we can figure it out would be The Unification of all four Forces.

  48. Parallel Universes • But what about those other dimensions? • They allow parallel universes – many kinds…

  49. The Other You’s • Implications of an infinite flat universe • 1011510 meters

More Related