Twistor (47 page)

4.
The Dark Matter and Solar Neutrino Problems.
These are problems of contemporary physics that are at present unsolved. The dark matter problem comes from attempts to estimate the density of matter in the universe by various methods, in effect 'weighing' the universe. One method uses Doppler shift techniques to estimate the orbital velocities of bright stars near the periphery of galactic clusters, in effect treating the whole cluster as a single mass producing the observed orbit. The result is that only a small fraction of the estimated mass can be accounted for as visible stars, even after corrections for subluminous Jupiter-like bodies and interstellar hydrogen are included. Estimates of the matter density in the early Big Bang that would have been required to produce the observed abundances of deuterium, helium, and lithium in the present universe also lead to a similar mass discrepancy. The conclusion is that at best we can account for only about one seventh of the mass in the universe,
with
the remaining six sevenths in some mysterious 'dark matter' form.

The solar neutrino problem arises from a decades-long effort by Ray Davis and his coworkers from Brookhaven National Laboratory to use a very large counter system buried deep underground in a South Dakota gold mine to detect neutrinos from the sun. This massive effort detects a solar neutrino flux that is only one third of that predicted by standard solar models.

The structure of the shadow universes in
Twistor
is contrived to accommodate these two scientific mysteries: six extra shadow universes to account for the dark matter problem, and two extra suns so that our own sun need produce only one third of the net neutrino flux. This, at least at the superficial level, 'explains' both results. Whether this 'explanation' could withstand the rigors of closer scientific scrutiny is not known.

5.
The Geophysics and Astrophysics of Shadow Worlds.
An underlying assumption of
Twistor
is that our Earth and sun have shadow-matter counterparts in two of the other shadow universes, with Earthlike planets occupying the same orbits and even having the same rotational periods. Except for the matching rotational periods this is fairly plausible from the viewpoint of planet formation, since the gravity well produced by a planet in one universe would tend to attract matter in the others also. However, this scenario may have problems in the areas of both geophysics and astrophysics. On the question of whether two shadow Earths could be superimposed on ours in a plausible geophysical model, Paul's arguments in
Chapter 17
of
Twistor
are essentially my own. Because conventional methods hypothesize an enormous density for the Earth's interior, it would seem to be possible to accommodate two more Earths by simply reducing the density of the interior of each by one third. Whether such a model could be made compatible with the
phase
boundaries and structures in the Earth's
interior
known from seismology, however, I cannot judge.

Similarly, I do not know whether conventional astrophysical models of the sun could permit two thirds of the sun's hydrogen to be inert matter which contributes only to the gravitational field and still produce enough fusion and energy generation. I am doubtful if this could be fitted within the envelope of acceptable variants of solar models. As far as I know, it has never been considered as a solution to the solar neutrino problem, although it is no more bizarre than several other ideas that have been taken quite seriously in the literature of astrophysics.

The locking of the rotational periods of superimposed shadow Earths is needed in the novel so that all three planets (or at least two of them) rotate at the same rate. Otherwise the treehouse might have reappeared at any place on Earth that is located at 47° north latitude. There is a mechanism for locking the rotational periods, and I am grateful to Bob Forward for pointing it out. The tidal forces arising from irregularities in the mass distributions of the three planets (mountains, oceans, concentrations of heavy minerals, etc.) would provide a damping mechanism that would eventually bring the bodies to the same rotational period. I have not calculated the time constant associated with such damping, but it is plausible that the billion or so years since Earth's formation would be sufficient.

An object, i.e., the apparatus lost in Part 1, that is twisted into one of the empty universes and left to orbit there under the influence of the Earth's gravitational field will have very peculiar non-Keplerian orbital dynamics because the gravitational force would not be a simple inverse square law force. Rather, it would be fairly well approximated by a Hooke's law force that grows linearly with distance from the center of motion. The orbiting object would fall repeatedly through the Earth in a precessing orbit, passing within a few hundred
miles
of Earth-center on each trip and traversing from one side of the planet to the other in about thirty-eight minutes. The orbit would bring the object repeatedly back to or near ground level at widely scattered points on the Earth's surface.

I wrote an orbital dynamics program to investigate such orbits. For input I needed the best available data on the interior density profile of the Earth, and I had to use double-precision FORTRAN on my wife's Macintosh SE to get sufficient accuracy. The opportunity to 'launch' a space vehicle by letting it fall through the Earth would lead to a completely new form of space technology and also to very rapid and energy-efficient surface transportation from one place to another on the Earth. But I will save that for a sequel to
Twistor.

6.
Hacking and BitNet.
The computer-system penetration techniques used by Flash in the hacking scenes in
Twistor
are all known techniques which have been used to penetrate protected computer systems. However, as is said of the wrestling holds shown on TV, the reader is cautioned not to try these in his own home. One reason is that they are illegal and are growing more so as state legislatures gain better understanding of computer crime and write better computer-protection laws. Another reason is that these techniques are presently well known, even to a nonhacker like the author. Software producers and system managers have already set up countermeasures to entrap and defeat any hackers who might attempt to use many of them. They are used in
Twistor
to create the 'feel' of the penetration of a well-protected computer system and should not be taken as an instruction manual on how to do so.

BitNet is an actual worldwide computer network that is already in very active use by the physics community. However, at present it is used primarily for 'mail' messages between users and for the transmission of data files
and
programs. It is not in general use for the transmission of scientific papers and preprints because these usually include a number of figures; for example, line drawings of equipment or data plots. Although CompuServe's GIF standard, Adobe's Post Script, and several others are looming on the horizon, there is presently no universal graphics standard that would permit the routine inclusion of figures in scientific papers, and so they are still distributed by conventional mail.

It is a good bet that this will soon change. The scientific journals published by the American Institute of Physics,
e.g.,Physical Review,
already accept manuscripts submitted on computer media. It is very likely that within a decade physics papers for journal publication complete with drawings and figures will be submitted and preprints of such papers will be routinely circulated by BitNet or its successor. One can only hope that publishers of works of fiction (like the present novel) will also eventually emerge from the nineteenth century and adopt similar technology.

John Cramer

Seattle, Washington

December 22, 1987

About
the Author

John G. Cramer
is Professor Emeritus, Physics, at the University of Washington (UW) in Seattle, where he has had five decades of experience in teaching undergraduate and graduate level physics. He has done cutting-edge research in experimental and theoretical nuclear and ultra-relativistic heavy ion physics, including active participation in Experiments NA35 and NA49 at CERN, Geneva, Switzerland, and the STAR Experiment at RHIC, Brookhaven National Laboratory, Long Island, NY. He has also worked in the foundations of quantum mechanics (QM), is the originator of QM's transactional interpretation (TI), and his new book about the TI,
The Quantum Handshake - Entanglement, Nonlocality and Transactions,
has just been published.

John is the author of the award-nominated hard science fiction novels
Twistor
and
Einstein's Bridge.
John is also the author of over 181 popular-level science articles published bimonthly from 1984 to the present in his "The Alternate View" columns appearing in every other issue of
Analog Science Fiction and Fact Magazine
and available online.

John was born in Houston, Texas, on October 24, 1934, and was educated in the Houston Public Schools (Poe, Lanier, Lamar) and at Rice University, where he received a BA (1957), MA (1959), and PhD (1961) in Experimental
Nuclear
Physics. He began his professional physics career as a Posdoc and then Assistant Professor at Indiana University, Bloomington, Indiana (1961–64) before joining the Physics Faculty of the University of Washington\ index {University of Washington}. John and his wife Pauline live in the View Ridge neighborhood of Seattle, Washington, with their three Shetland Sheepdogs, MACH-4 Lancelot, MACH Viviane, and Taliesin.