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http://timeandquantummechanics.com Multiverse - Balticon, May 23rd, 2015 John Ashmead Anyway? Just how many universes are there,

How many universes are there, anyway

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Page 1: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015John Ashmead Anyway?

Just how many universes are there,

Page 2: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

• Rainbow gravity

• Gravity leaking into nearby dimensions

• Miniature black holes

Page 3: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

• The multiverse today

• The problem of fine-tuning

• A scientific hypothesis?

• What are the odds?

Page 4: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

The Multiverse Today

• A brief history of the multiverse

• The edge of the known

• From the Big Bang to now

Page 5: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

A brief history of the Multiverse

• Eratothenes’s Earth

• Kepler’s Moon

• Galileo’s Jupiter

• Wright’s Galaxies

• Bessel’s Star

Page 6: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

• Chief Librarian at Alexandria at 245 BC

• Sieve of primes

• Beta/Pentathelete

• Camel-Days

• Right order of magnitude

Eratothenes’ Earth

Page 7: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Kepler’s Somnium (1608+)

• Autobiographical

• Revised thru his life

• Copernican theory

• The view from the moon

Page 8: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

• Careful reasoning

• Notebooks

• Time series

• A lot to love here

Galileo & The Moons of Jupiter(1610)

Page 9: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Wright’s Galaxies (1750)

• Milky way as galaxy

• Nebulae as galaxies

• An indifferent universe

Page 10: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Bessel’s Star (1838)

Page 11: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Cosmic Distance Ladder

• Parallax (Blue)

• Standard Candles (Light Orange)

• Supernovae (Red)

• The red shift (Dull green)

Page 12: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Page 13: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

• 30 billion years away

• But only 13.7 billion years since start?

• Space has been expanding!

Page 14: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Finite but no edge!

• Finite but no edge

• It’s getting bigger every minute

• Now is a good time for observers

Page 15: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Big Bang Theory (De Luce)

• Only theory with a TV show

• Robert Grossteste, 1175 - 1253.

• The Big Bang theory is not about the Big Bang

Page 16: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

• Why is the universe so flat?

• With matching temperature

• & curvature?

Page 17: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Too Hot to Shine• Only ionized

particles

• The unfortunate photon no sooner escapes from one particle

• Than it is absorbed by another!

Page 18: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Tri-Alpha Process• Helium

stable

• Beryllium (next) is NOT

• But there is a resonance with Carbon

• Tunnel thru!

Page 19: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

The problem of fine-tuning

• Just six numbers

• Quantum fluctuations

• String theory

Page 20: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Page 21: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Anthropic testsCurious when you think about it that the universe is perfectly

adapted for velociraptors

What if there are lots of universes & we

just got lucky?I see dinner!

Page 22: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Vulcan Science Directorate Thinks not

A parallel universe. The science directorate has examined all these theories. They've found no evidence of alternate realities.

Page 23: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Quantum Fluctuations

• Quantum fluctuations

• Fractals

• Led to universe

• And galaxies

Page 24: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Eternal Inflation• Parts of the mega

universe suddenly cool out

• Creating a bubble universe

• That inflates with specific values of the fundamental physical constants

Page 25: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Live, Die, Repeat• Origin of species

• “Generate & test”

• Galaxies, stars, planets, & us

• Universes & their observers

• And theories of the multiverse, e.g. String Theory

Page 26: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

String theory• Most popular today

• Gets rid of some infinities

• Lets us combine particle physics & gravity

• 10 dimensions for superstrings

Page 27: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Compactification

Page 28: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Calabi-Yau Manifolds

• The “extra” dimensions are curled up into complex structures

• Many possible ways to do this

Page 29: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

String-scape• 10^500

possibilities

• Most are uninteresting

• A few “Happy Valleys”

Page 30: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Fringe Science?• Hot scientists?

• Equations?

• Intense but puzzled expressions?

• Fate of the universe at stake?

Page 31: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

How to think about WeirdThings

• Testability

• Fruitfulness

• Scope

• Simplicity

• Conservatism

Page 32: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Testability

Page 33: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Cosmological Microwave Background

Page 34: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Bubble universes

Page 35: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Bubbles in the CMB?

• Nearby parallel universe

• Leaves smudge on the CMB

• Sister universes?

Page 36: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Gravitational waves

• Distant universes

• Remnants of collisions

• From before the Big Bang

Page 37: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Fruitfulness

• Gives you something to look for at small scales

• And at large

• Can rock the mind loose from hard-wired assumptions

Page 38: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Scope

• Largest possible scope

• See as far as possible

• And then drive imagination a bit further than that

Page 39: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Simplicity

• # of hypotheses

• not number of parts, but the kinds of parts

• is a Calabi-Yau manifold simple or complex?

Page 40: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Wheeler’s Radical Conservatism

• The combination of Eternal Inflation & String theory gives the multiverse as a straight forward prediction

• Gellmann’s totalitarian principle + the 30 odd constants also imply multiverse

• And Many Worlds Interpretation implies that the multiverse a natural implication of quantum mechanics

Page 41: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Page 42: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

The universe whisperer

Page 43: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

• Shift your assumptions to match those of your target world

• Absurd

• And profound

Syllogismobile

Page 44: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

one universe or many?

Page 45: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

Thanks!

• Balticon & Miriam Kelly

• Ferne Welch

• Brenda Welch & Jamie Laird

• Other quasi-willing ears

Page 46: How many universes are there, anyway

http://timeandquantummechanics.comMultiverse - Balticon, May 23rd, 2015

• Stenger - God & the Multiverse - 2014

• Greene - Hidden Reality - 2011

• Barrow - The Book of Universes - 2011

• Clegg - Before the Big Bang - 2009

• Susskind - The Cosmic Landscape - 2006