Thursday, May 25, 2017

Physics in the Year 2116

Last year Physics Today ran an essay competition called "Physics in 2116." The idea was to write a science article that might appear in Physics Today 100 years from now. Motivated largely by the enormous prize money, I entered the competition but, alas, mine was not among the winning entries. As the article itself is not really suitable as either a science fiction story or a nonfiction article, I am presenting it here for your amusement. Be sure to read the footnotes.

Improved theory of quantum gravity

XNEWTON has modified the current theory of quantum gravity and has proposed tests to be carried out at the Center for Experimental Relativity.


For most of the 20th and 21st centuries, a quantum theory of gravity remained an elusive goal.  Much of the problem lay with the difficulty of testing general relativity in the strong field regime, and even weak-field tests were all but impossible to verify in the laboratory.  All of this changed in 2077 with the detection of relic kiloton-mass black holes,[1] and the discovery that they emitted Hawking radiation at a much lower rate than originally predicted.[2]
            While numerous theories of quantum gravity were proposed in the wake of this discovery, it was the advent of practical quantum computing in the past 20 years that led to the first genuine breakthroughs.  Modern computer programs capable of doing theoretical physics can trace their roots all of way back to Hod Lipson’s Eureqa program at the turn of the 21st century.[3]  With the development of deep-learning programs running on quantum computers, these engines achieved the ability to generate physical theories to account for any given set of input data.  XGALILEO, the precursor to XNEWTON at the Tata Institute for AI Theoretical Physics (TIAITP) in Mumbai, was the first to produce a theory of quantum gravity that explained the modified Hawking radiation rate.  This new theory allowed scientists to understand the processes that occurred in the very early universe, well above the Planck energy.
            As Padma Gupta at TIAITP explains, “With access to all of the world’s published experimental data, XNEWTON is always updating its theoretical models.  Recently, some new set of data – and we’re not really sure which data this was – caused a significant change in its model for quantum gravity.  XNEWTON has now proposed a number of experimental tests of the new theory, and we’ll send those over to the Center for Experimental Relativity (CER) so they can set up the experiments.  Of course, we’ll follow the Melbourne Protocol – nobody wants a repeat of the Princeton disaster.” [4]  (The Melbourne Protocol prohibits direct control by a deep-learning computer program of experiments proposed by that same program.[5]  It was instituted following the results of the insertion of malicious code into XGALILEO in 2103.)
            The Center for Experimental Relativity is located at the L2 Earth-Sun Lagrange point.  The heart of the laboratory consists of two black holes, with masses of 1.2 million kilograms and 1.4 million kilograms, respectively, orbiting their common center of mass.  At a separation of 1 cm, the period of the orbit is 0.5 seconds.  The two black holes carry small electric charges of opposite sign. “This serves a dual purpose,” explains CER Director Tobias Schmidt.  “It allows for electromagnetic confinement of the black holes, and by measuring the oscillating electric field near the black holes we can determine their trajectories with exquisite precision.”

FIGURE 1.  THE CENTER FOR EXPERIMENTAL RELATIVITY is located at the L2 Earth-Sun Lagrange point.  (Courtesy of NASA.)

The Center for Experimental Relativity relocated into space six years ago from its original site in Potsdam following the public outcry over the loss of one of its black holes. According to Schmidt, “Space is really a much better location for these kinds of experiments. We’ve got a built-in vacuum for our long-baseline interferometers, and we don’t have to support the black holes against the Earth’s gravitational pull. And just to be clear – we never lost a black hole.[6]  When you ‘lose’ something, you don’t know where it is. We know exactly what happened to that black hole when our electromagnetic confinement system unexpectedly failed. It sank down to the center of the Earth’s core, where it poses no danger.” While the black hole continues to consume material in the core, the rate is so slow that it will have no appreciable effect on the Earth over many times the current age of the universe.
            Once the results of the experiments proposed by XNEWTON are relayed back to TIAITP, XNEWTON will determine whether the new theory is supported or refuted by the new data.  Over the past decade, XNEWTON’s success rate has exceeded 90%; fewer than one in ten of its new proposed theories have been falsified by subsequent experiments.
Gupta and the other TIAITP computer scientists continue working to improve the deep-learning software. “Our aim is to drive the success rate for new theories above 99%,” says Gupta.  She rejects recent claims that XNEWTON has made human theoretical physicists redundant.  “Theorists? Of course we still need them,” she says. “We need people to interpret XNEWTON’s theoretical constructions and explain them to the rest of the scientific community.  But if you’re talking about human physicists coming up with original theories on their own – of course that’s obsolete now. Computers just do some things better than we do, and we’ve had no trouble delegating those responsibilities to them. Do we still do arithmetic with pencil and paper? Or drive our own cars?  Or let people perform surgery? Or raise our own children? And don’t forget the mess we made of things when humans still ran the government.”
            The experiments requested by XNEWTON will begin next month, and scientists are expecting the new theory to be confirmed or rejected by the end of the year.

Robert Scherrer is in the Department of Physics and Astronomy at Vanderbilt University, Nashville, Tennessee 37205, Independent Southern States of America

[1] J.W. Hoerner, et al., “Discovery of 106 kg relic black holes,” Nature DAI:033234882 (2077).
[2]M.J. Javier and C.D. Maxvill, “Upper limit on the decay rate of kiloton-mass black holes,” Phys. Rev. Lett. DAI:033255020 (2078).
[3] M. Schmidt and H. Lipson, “Distilling free-form natural laws from experimental data,” Science 324, 81 (2009).
[4] T.M. Shannon, “When will central New Jersey be habitable again?” Physics Today 157, 23 (2104).
[5] R.C. Washburn, “The Melbourne Protocol promises improved safety,” Nature DAI:098351844 (2108).
[6] R. Gibson and D.W. Ricketts, “How did the Center for Experimental Relativity lose a black hole?” Physics Today 163, 47 (2110).

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