The big news was that the OPERA project had done a second version of the experiment that saw superluminal neutrinos, dealing with some of the objections (objectinos?) to their first results.  They sacrificed quantity of neutrinos to quality:  going from 16,000 to 20, but getting much tighter time resolution.   This made the New York Times Saturday morning, so I clipped the headline for use in a slide.  Good stuff, but of course everyone wants to see Fermilab & others reproduce the experimental results.

However the combination of refreshing the talk, roadwork on Interstate 76, & a parade or some such on the Benjamin Franklin Parkway meant I got in with no time to check the AV setup before the talk.  While the impromptu AV crew wrastled the difficulties into submission (thanks Margaret Trebling, Jay Wile, Ron Bushyager, & Ferne Welch!) I invited the audience to “open the theater of your mind” & painted word pictures thereon till the AV was working.  Didn’t take the crew long:  we hadn’t even gotten past the Black Death slide before we had light!  Actually I think the difficulties may have helped the talk go over; shared troubles create bonding between speaker & audience.  Lots of good questions; SRO crowd.

As I promised then, I have posted the talk as Keynote, PDF, PowerPoint, & HTML.  Comments, questions, and suggestions very welcome!

Had a lot of fun on the six panels I was on; will post on them over the next few days.

11/23/2011 I’ve just updated the references page to include the references from the talk.

Full schedule:

Fri 8:00 PM in Plaza V (Five) (1 hour)
THE FICTION OF CHINA MIEVILLE (771)

   [Panelists: John Ashmead (mod), Meredith Schwartz, Andrew C. Murphy]

   Exploring the work of the popular author of Perdido Street Station
   and others.  What makes his work so special

Sat 12:00 PM in Crystal Ballroom Two (1 hour)
ALIEN LIFE IN THE SOLAR SYSTEM (848)

   [Panelists: John Ashmead (mod), Alexis Gilliland, Eric Kotani]

   Making up planets around stars we do not know is relatively easy.
   Let's talk about a more difficult approach... imagining alien
   lifeforms in the solar system as we now know it

Sat 1:00 PM in Plaza III (Three) (1 hour)
NOT YOUR GRANDFATHER'S GRAVITY (890)

   [Speaker: John Ashmead]

   Einstein's theory of gravity is our best to date -- even though it
   is known to be incomplete. Now it is in the crosshairs! Several
   competitors -- string theory, loop quantum gravity, emergent gravity
   -- have come out in the open & it's a horse race! We'll look at
   weird twists of space & time, dark energy, neutrinos just spotted
   going faster than light, the curiously shy Higgs particle, & the
   whole universe from its birth in the Big Bang to its death -- &
   possible rebirth

Sat 7:00 PM in Plaza II (Two) (1 hour)
FUTURE WAR (748)

   [Panelists: Alexis Gilliland (mod), John Ashmead, Amy Bailey, Frank
   O'Brien]

   It's commonly said among Air Force officers today that the last
   human fighter pilots have been born. Drones and remotely-piloted
   planes are the future of air warfare. What about the other branches
   of the armed forces? Robots are filling more and more roles. Will
   there come a point where there are few or no human soldiers? What
   are the implications? Is this a good or bad development

Sat 8:00 PM in Plaza V (Five) (1 hour)
TAPPING THE QUANTUM FOAM: CAN "ZERO POINT" ENERGY EVER BE REAL? (902)

   [Panelists: John Ashmead (mod), Jay Wile, Marvin Kaye]

   Infinite free energy drawn from the quantum vacuum - con games and
   pseudoscience today. But does our present understanding of quantum
   physics suggest it could ever become reality? Would the process pose
   any dangers

Sat 10:00 PM in Plaza III (Three) (1 hour)
WHAT MAKES H.P. LOVECRAFT UNSTOPPABLE? (826)

   [Panelists: John Ashmead (mod), James Chambers, Chris Pisano,
   Darrell Schweitzer, Eric Avedissian, Roman Ranieri]

   Great writers, we contend, are the ones the critics cannot stop.
   Major critics, notably Edmund Wilson, tried, but to no avail. Today
   Lovecraft is famous world-wide.  Yet when he died in 1937, his only
   published book was a wretchedly amateur production which had barely
   sold a hundred copies.  What made the difference?  Was it all those
   role-playing games and plish Cthulhu toys? The movies? Or something
   inherent in the texts

Sun 1:00 PM in Plaza V (Five) (1 hour)
DARK MATTER GETS DARKER: NEW DISCOVERIES, NEW MYSTERIES (904)

   [Panelists: John Ashmead (mod), Paul Halpern, Jay Wile, Eric Kotani]

   Dark matter detection experiment CoGeNT has seen a possible signal,
   similar to the much-disputed DAMA/LIBRA result, that might confirm
   the controversial claim that dark matter has not only been observed,
   but that it varies with the seasons. Meanwhile the XENON100 detector
   has just released results from its most recent rum: they don’t see
   anything. 

   Are we closing in on dark matter, or is it getting more mysterious?

I’m also doing panels on Hard SF & Alien Cultures, Making Fictional Cities Come Alive (when real ones do, run!), and Astronomy & Science Fiction.  If you are in the DC area, I look forward to seeing you.

Pre-talk I ran into a lot of people fascinated with gravity, had lots of great conversations, & spent part of Saturday morning folding in some of the suggestions.

As I said at the talk, this provided a perfect example of how the Higgs boson gives particles mass via interactions.  In principle, you could walk from one end of the hotel to the other in under five minutes.  But in practice, with all the conversations, it could take three hours!  Ditto the Higgs.  The electron wants to just zip thru space, but it keeps interacting with Higgs particles & losing a bit of time with each interaction. From a distance, it looks as if the electron — massless tho it may have been at the start — has acquired mass.

Very enthusiastic crowd at the talk.  When I pointed out that we owed the black plague three debts of gratitude because it:

1. Paved the way for the industrial revolution by making serfs valuable (as there were many fewer).
2. Gave the population of Europe significantly enhanced resistance to HIV.
3. Gave Newton time to think about mathematics, light, & orbits:  ”All this was in the two plague years of 1665 and 1666, for in those days I was in my prime of age for invention, and minded mathematics and philosophy more than at any time since.”

the crowd gave a round of applause to the Black Plague!  :)

Post talk I got a lot of positive feedback & may do the talk again.  Because of the new material the last few slides were (more than a bit) rushed. To recap, the main new developments in gravity over the last two years or so are (obviously in my opinion):

1. Verlinde’s “On the Origin of Gravity and the Laws of Newton” derives gravity from thermodynamics, letting us talk meaningfully about gravity even without a confirmed theory of quantum gravity.
2. The universe is about 95% mysterious:  The WMAP & other results about dark energy & dark matter are now very solid, letting us say  that the universe is only 5% baryonic matter, stuff we know about, with 22% dark matter, & 73% dark energy!
3. New telescopes & new kinds of telescopes are looking for neutrinos, antimatter, WIMPS & other candidate sources of dark matter, & gravitational radiation.
4. The Large Hadron Collider is online, looking for the Higgs (widely thought responsible for giving particles mass) & anything that might out there, i.e. signs of Calabi-Yau dimensions.

I’ve uploaded the latest version of the talk as pdf, keynote, power point, & html.  Given that I find there are new developments just out each time I work on this, by the time you read this, it will already be at least slightly behind the times!

Several possible modifications to Einstein’s theory have been proposed & may even have some experimental support; in addition to string theory & loop quantum gravity, is gravity a thermodynamic effect? Astronomers are looking hard at gravity waves in search of clues as to the origin of the universe (or even as to whether the universe had an origin), and …!

I’ve just finished the talk — main problem, too many interesting possible side channels — and have uploaded it as pdf,  keynote, power point, & html.  Comments welcome!

I’d like to thank Brent Warner & his colleagues for their warm welcome & all the feedback during the talk.  Brent tells me he particularly liked the quote from an Astounding Science Fiction reader (1933):

“Why pick on grandfather? It seems that the only way to prove that time travel is impossible is to cite a case of killing one’s own grandfather. This incessant murdering of harmless ancestors must stop. Let’s see some wide-awake fan make up some other method of disproving the theory”*

As I say in the talk, if the current literature is on target, the grandfather & other paradoxes are cancelled out by interference by the time machine’s wave function with itself.

Brent & his NASA colleagues were kind enough to provide lunch & a fascinating tool of the facilities:  they manage the Hubble & are working on the James Webb.  Huge rooms with vast devices for subjecting equipment to high G’s, vacuum, heat, noise, vibration, & every other insult that it will need to be able to withstand during launch or in space:  gives one a real sense of just how hard it is to get this stuff to work!

*as quoted by Paul Nahin in his Time Machines: time travel in physics, metaphysics, and science fiction

The pdf & keynote versions are now online.

The run thru will be at the Winsor room at the Radnor Memorial Library on March 12 at 2pm.  This is a few hundred feet from the main intersection in Wayne, PA.

The talk is basically the Physics Of Paradox talk, but more focused on the physics than the science fiction (tho in this area it can be hard to tell them apart) & with animations.

Since this is a complete redo of the talk, I’m hoping to get feedback on timing & clarity & focus & such like!

Please come!  And criticize!

Thanks!

– John Ashmead

ABSTRACT – Einstein’s general relativity is the leading theory of gravity. Simple and elegant, it has passed all available experimental tests including: deflection of light by gravity, precession of orbital apsides, gravitational time dilation (used in GPS), and frame-dragging.

However, general relativity makes a number of counter-intuitive predictions. In particular, trajectories looping around massive, rapidly rotating stars or passing through a wormhole can close on themselves in time, creating closed timelike curves (CTCs).

This creates the possibility of “grandfather” and “bootstrap” paradoxes. Recent work by Greenberger & Svozil, and others, however, questions this conclusion. That work suggests that when quantum mechanical effects are included, the paradoxes become self-canceling, eliminated by destructive interference within the wave function. If the paradoxes are self-canceling, then closed time-like curves are possible. If they are possible, can we create or detect them?

Several authors have suggested that we look for evanescent wormholes with the Large Hadron Collider. If we find them, we may be at the edge of temporal paradox. While the only safe prediction in this area is that there are no safe predictions, we look at the implications of this for general relativity, quantum mechanics, & causality.

Quite a lot of fun subjects for my panels:  Augmented Reality (for those who can’t get enough reality), Time Travel & Free Will, Are the Laws of Physics Laws (or really more just Guidelines?), Is the Universe a Hologram (& can I leave the Holodeck?), my Physics of Paradox talk in its final & perfected version, & What Came Before the Big Bang (& are we in trouble with whatever it is?)

[I've augmented the reality of the Physics of Paradox slides by adding the spoken text to them:  see the Keynote (for Mac users), PowerPoint (for PC users), and  annotated pdf version.]

My complete schedule is: