HAWKING vs SUSSKIND

It's a fun time to be alive! As if reading my mind ("no such thing as too many programs and books about cosmology"), TVO's Big Ideas program today was the the 2011 Sackler Public Lecture at the University of Toronto given by Leonard Susskind on June 28, 2011. In the lecture, he described in simplified terms (yes, we need that!) the idea of the universe being a giant hologram. If this sounds familiar, note Brian Greene's ending remarks here ("imagine reality as a hologram").

Leonard Susskind and Stephen Hawking disagreed about what would happen to the information and matter stored in a black hole when it evaporates. Since I hadn't given ANY thought to a black hole evaporating (some physicists argue that black holes themselves may not even exist), this is all new and exciting to me. Not to writers at Wikipedia, though. I have a LOT of catching up to do re: theories in cosmology. See these and other articles at Wikipedia:

http://en.wikipedia.org/wiki/Leonard_Susskind

http://en.wikipedia.org/wiki/Black_hole_information_paradox

Image taken from Wikipedia (source: NASA)

FABRIC of COSMOS

http://www.pbs.org/wgbh/nova/physics/fabric-of-cosmos.html

Acclaimed physicist Brian Greene reveals a mind-boggling reality beneath the surface of our everyday world.

"The Fabric of the Cosmos," a four-hour series based on the book by renowned physicist and author Brian Greene, takes us to the frontiers of physics to see how scientists are piecing together the most complete picture yet of space, time, and the universe.

Airing 11/2, 11/9, 11/16 and 11/23 on PBS
What is Space?
The Illusion of Time
Quantum Leap
Universe or Multiverse?

[I get this via PBS channel #388 (at SHAW DIRECT SATELLITE) WNED Buffalo-Toronto]


Quick Summary of Part 1: What is Space?

Empty space is not nothing; it is something, it has properties, e.g., it can twist.

Newton's space: a passive framework like the stage used for a play; space is a real, physical thing.

Einstein: the nature of light - constant speed of light is 671 million mph; think of a car with headlights on - the speed of its light coming at you when stopped is same as when car approaches you at 40 mph because light can't go any faster. The speed of light is absolute.

Einstein: nature of gravity - spacetime can stretch and bend like a rubber sheet; it is dynamic and flexible; gravity IS the shape of spacetime.

In 1950's Leonard Schiff conceived a project to test general relativity using orbiting gyroscopes: Gravity Probe B. The idea is to measure how space and time are "warped" by the presence of the Earth. See http://en.wikipedia.org/wiki/Gravity_Probe_B

Quantum Mechanics: empty space is full of activity - particles pop into and out of existence and empty space has enough force to push on matter.

Peter Higgs - Univ. Edinburgh - the Higgs field was proposed by Higgs and others to provide mass to particles. http://en.wikipedia.org/wiki/Peter_Higgs

Big Bang was 14 billion years ago - will the universe continue to expand or will it collapse?

Saul Perlmutter investigated supernovae and discovered that the universe's expansion is accelerating. Something is counteracting the pull of gravity. "Dark energy" has been proposed as the cause. [Fun note: Perlmutter was mentioned recently on a The Big Bang Theory episode in which Sheldon wants to go to a lecture given by Perlmutter just so he can debunk the Nobel laureate's theories publicly.]

Einstein's cosmological constant Λ was introduced to allow for a static universe. He later called it his biggest blunder. The strange thing is: recent improved astronomical techniques have found that a positive value of Λ is needed to explain the accelerating universe.

The strangest revelation (revelation or crazy idea?) in "Part 1: What is Space?" is this:

* when something falls into a black hole it is lost forever; at least, the 3D version of that something; BUT the 2D version (information about the thing) stays at the black hole's surface

* imagine reality as a hologram -- with the 3D part = things in the universe and the 2D part = the surface of the universe.

I'm excited about the next episode: The Illusion of Time

REINVENTING GRAVITY

Reading Reinventing Gravity by John W. Moffat is like reading a mystery. He builds his case towards an alternative theory of gravity gradually by taking us through the history of science to demonstrate how old theories need to be updated or overthrown when more precise observations are made of nature.

The mystery of the nature of space-time is revealed and all seems well until newer observations and measurements show flaws in Newton's and Einstein's theories. Black holes, dark matter, and dark energy have been postulated to update those theories to fit new observations. They have been accepted by many scientists but do these objects really exist?

Moffat writes:

Let me state the current situation very clearly. There are only two ways of explaining the wealth of observational data showing the surprisingly fast rotational speeds of stars in galaxies and the stability of clusters: Either dark matter exists and presumably will be found, and Newton's and Einstein's gravity theories will remain intact; or dark matter does not exist and we must find a new gravity theory.

This book is a GREAT read for anyone who fits into the author's intended audience: "the curious non-physicist who loves science" or "the reader with a more technical background in physics".

Moffat's alternative theory refutes some of the statements in Timeline of the Universe shown below.

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Cosmic Microwave Background (CMB) Radiation

The detailed, all-sky picture of the infant universe created from seven years of WMAP data. The image reveals 13.7 billion year old temperature fluctuations (shown as color differences) that correspond to the seeds that grew to become the galaxies. The signal from the our Galaxy was subtracted using the multi-frequency data. This image shows a temperature range of ± 200 microKelvin.

Credit: NASA / WMAP Science Team

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Timeline of the Universe

A representation of the evolution of the universe over 13.7 billion years. The far left depicts the earliest moment we can now probe, when a period of "inflation" produced a burst of exponential growth in the universe. (Size is depicted by the vertical extent of the grid in this graphic.) For the next several billion years, the expansion of the universe gradually slowed down as the matter in the universe pulled on itself via gravity. More recently, the expansion has begun to speed up again as the repulsive effects of dark energy have come to dominate the expansion of the universe. The afterglow light seen by WMAP was emitted about 380,000 years after inflation and has traversed the universe largely unimpeded since then. The conditions of earlier times are imprinted on this light; it also forms a backlight for later developments of the universe.

Credit: NASA / WMAP Science Team

COSMOLOGY

Is Everything We Know About The Universe Wrong?

"Dark flow is the latest in a long line of phenomena that have threatened to re-write the textbooks. Does it herald a new era of understanding, or does it simply mean that everything we know about the universe is wrong?"

9 PM Monday on Discovery Science. I enjoyed this hour about the standard model of cosmology and various concepts that had to be added as newer data became available. It will be repeated Tuesday, September 20 2011 12:00 AM. http://www.sciencechannel.ca/

Summary: "Dark Flow" is the latest finding from examinations of data collected about our universe. The hour covers the Big Bang theory (standard model of cosmology); the need to explain why the temperature is homogeneous throughout the universe (not an expected result of a Big Bang); Alan Guth's concept of inflation that answers the homogeneous temperature problem; rotation speeds of galaxies that led to the idea of dark matter which is required to explain why galaxies don't fly apart; the curious problem of how to detect dark matter; and finally the "dark flow" of matter discovered upon examination of CMB data (the cosmic microwave background). Is there more structure outside of our universe? Alan Guth predicted that our universe was part of a larger structure.

It doesn't get more fun than the exploration of ideas about cosmology!

Herschel Views the Milky Way: looking toward the constellation of the Southern Cross. Photo from Herschel Space Observatory.

THE GRAND DESIGN

HOT, sunny beginning for September on the 2nd; a glorious Saturday that I spent at Farran Park, watching the lovely dogs in the conformation rings. It was at least 30°C!

Monday the 4th is much colder (16°C); an overcast gray day. This combination of sun and rain made the grass grow like crazy in 4 days.

Gray weather invites me to snuggle up with Terri & Flower and a good book. The great book that I'm reading now is The Grand Design by Stephen Hawking and Leonard Mlodinow. It's a marvelous overview connecting ideas and theories in physics from Newton's gravity through Feynman's view of quantum theory to M-theory; from the quarks that form protons and neutrons to the expanding universe/multiverse. With this model-dependent perspective of reality under your belt, various physics theories seem to fit into the jigsaw puzzle of Life, The Universe, and Everything more understandably. As some critics say, Hawking and Mlodinow may be too confident about M-theory and it may be trashed in the future but for this time and place in our universe, I like how well they explain all the concepts. June 19, 2012: Came across this set of pages about The Grand Design ... http://www.livescience.com/18035-stephen-hawking-book-physics.html