Intersection: Worldcon '95

53rd World Science Fiction Convention
24 - 28 August 1995, Scottish Exhibition Centre, Glasgow

GoHs: Samuel R. Delany , Gerry Anderson, (fan) Vin¢ Clarke, (filk) Bob Kanefsky

My second Worldcon. The large rooms at the SEC were fine, except for the one 'partitioned' into four smaller 'rooms', said partitioning wonderfully focusing the sound from each roomlet into the other three, allowing all four programme items to be experienced simultaneously.

Sadly, Jon Brunner died while attending the Con.

Programme highlights

(Nothing from the first day, since I was flat out with food poisoning -- not caused by Con food, I hasten to add):

Panel: Negative Matter Supported Wormholes

John Cramer , Geoffrey Landis, Greg Benford and Bob Forward on their recent joint physics paper.

Jack Cohen: Redesigning the Human Body for Fun and Fornication

If it weren't like this, how would it be?

A typical Jack Cohen talk, heavily illustrated with slides of cartoons and photographs:

John Cramer : Quantum Mechanics

The Transactional Interpretation of QM, as recently published in Rev.Mod.Phys.

Consider a photon emitted by a galaxy a billion years ago, now caught on a photographic plate on Earth. The Copenhagen Interpretation has a wave front spread over a billion-light-year sphere instantly collapsing to a point. Everett's Many-Worlds Interpretation has many parallel universes, some where the photon hits different plates at different times, some where it is never absorbed. The Transactional Interpretation considers both the retarded and advanced waves, constructively interfering with each other along the path between the emitter and absorber.

(Heisenberg's wave equation has two solutions, psi, and psi-star. Psi, the retarded wave, which travels forwards in time, is standard solution. Psi-star, the advanced wave, which travels backwards in time, is usually discarded as non-physical.)

CI requires swallowing instant collapse of wavefunctions, hence faster than light travel; Many Worlds requires swallowing prodigious replication; TI requires swallowing time travel.

CI, Many-Worlds, and TI are all interpretations of the same mathematics. So they have no different predictions or observable consequences. (The Transactional Interpretation might require an open universe to explain the arrow of time, to cater for 'non-observed' events of particles that are never absorbed.) Weinberg's attempt to add a small non-linear component (for which there is no evidence) would distinguish them: Everett can use it to communicate between parallel worlds; TI can use it to communicate backwards in time.

Ptolomey had the Earth at the centre of the Universe, and everything rotating around it. The Copenhagen Interpretation has the observer at the centre of the Universe, and everything collapsing around it: "The Collapsor of Wavefunctions".

Greg Bear

, in Blood Music , has a super-organism at the end that can "collapse any damn wavefunction it chooses".

Copernicus put the Earth in a non-privileged position. TI puts the observer in a non-privileged position. It isn't the observation that collapses the wavefunction: it is the collapse that lets the observer deduce that something has happened (and it has happened even if it is not observed).

Panel: Why is so Much Crap Published?

If SF readers are so discerning, why is there so much rubbish in print?

The publishers on the panel denied that this is the case! For example, John Jarrold bought only two unsolicited novels from the slush pile in the last 7 years.

Payment for a first novel ranges between $2000--$100,000, and half the books published do not recover their advances and printing costs.

Any book that makes you want to keep turning the pages does not deserve to be published
--- critic in The Times

Panel: You're the Aliens

What our depiction of aliens tells us about our own attitudes.

Most aliens are less 'alien' than some foreign human cultures. One panellist, British, "really liked the alien cultures I was reading about -- until I realised they weren't alien, they were American!"

Bob Forward: 21st Century Propulsion

101 ways of getting into and around in space without rockets.

And more, described in Bob Forward's new book Indistinguishable from Magic .

Panel: The Hero's Journey

The journey is a central feature of Fantasy. What does it tell us?

Hal Clement : Mercury

Facts about the planet closest to the Sun.

Panel: Turning Points

What makes a good, or believable, alternate history.

Bob Forward: Space Warps and Time Machines

How to make a time machine.

If you move one end of a wormhole close to the speed of light for a while, it becomes 'younger' that the other end. So you can go in today, and come out yesterday. If you draw your Cauchy surface properly, extending in the time dimension, this does not violate Cauchy's theorem.

You can have 'interesting' games of billiards with balls moving through wormholes, coming out before they go in, just in time to knock themselves in. There are 'paradoxical' solutions -- the future billiard ball stops its previous self going into the wormhole, so 'killing' its future ball (like shooting your own mother before you were born). But close to these solutions (within the uncertainty distance) are other, non-paradoxical, solutions that 'just' work. So ... if you go back in time to shoot your own mother, you will miss, but injure her enough to make her children bad shots...

And more, described in Bob Forward's new book Indistinguishable from Magic .