SF Bay Area Hiker Threatens the Foundations of Modern Science

One of the common refrains of the millions of people worldwide (more than 40 percent of the American public) who do not accept modern old-earth geology and evolutionary biology is that while some portions of modern science may be true, other portions, such as the notion that the earth and its fossils are many millions of years old, are suspect if not completely in error. In other words, many wish to “pick and choose” among the major precepts of modern science, accepting some but rejecting others.

One of my favorite activities is hiking in the many lovely mountains and hills in the SF Bay Area. In the past few years, I have taken up “geocaching” in conjunction with my hikes. This consists of using a GPS receiver to find some of the hundreds of thousands of “geocaches,” namely small containers with log sheets (and, in some cases, goodies such as hiking supplies), which are hidden at spots whose GPS coordinates (i.e., latitude and longitude) are provided at:
Geocaching serves to “spice up” the activity of hiking, and, as a bonus, having a quality GPS receiver with high-resolution built-in maps is valuable protection against getting lost or disoriented in the hills, particularly when one heads off-trail.

It occurred to me yesterday, while out hiking, that every time I head out to find a geocache in the hills, I threaten to overturn the foundations of modern science, including portions of geology, evolutionary biology, cosmology, quantum physics, special and general relativity, electrical engineering, computer science, scientific computing, numerical analysis and mathematics. I mean this quite literally: the GPS system is a symphony of modern science and technology, and if any “instrument” of the symphony were found to be faulty, the entire system might well collapse. So any time a hiker uses a GPS unit to fix his or her position, or any time a driver uses a GPS unit to display his or her current location on a street map, he or she is performing a very exacting test of a long string of scientific principles. If it doesn’t work, there is a chance (admittedly small) that he or she may have uncovered a serious flaw in some fundamental physical law.

Furthermore, if some fundamental physical law were found to be faulty, much of the rest of modern science would also be drawn into question, including, for instance, geology and evolutionary biology. One key body of evidence in these fields are the radiometric dates of various rock layers, which are based on measurements of trace amounts of certain radioactive isotopes in rock minerals. A key assumption in these measurements is that radioactivity is correctly described by certain key principles of quantum mechanics, and that these principles do not change measurably over time, nor are they affected by temperature, pressure, magnetism or chemical combination. In a similar way, modern big bang cosmology is based in part on general relativity, and the calculated age of the universe had better not be less than the age of rocks on the earth, or else we have a major problem! Thus any scientific experiments or measurements that threaten the integrity of either quantum physics or general relativity pose a grave challenge to both modern geology and evolutionary biology.

Now consider:

  1. A GPS position measurement involves measuring the time taken by radio signals to reach the receiver from multiple satellites, traveling at the speed of light, to an accuracy of approximately one nanosecond (one billionth of a second). In other words, a hiker fixing his/her position with a handheld GPS unit is making a scientific measurement with an accuracy unthinkable even for the most expensive laboratory equipment of just a few decades ago. Even a microscopically small percentage error in these measurements would result in a position far from the correct spot.
  2. The GPS system relies heavily on the principles of quantum physics. In particular, each of the 24 GPS system satellites, which orbit the earth at an altitude of approximately 20,200 km (12,550 miles), contains an atomic clock that must generate an exceedingly finely tuned frequency (10.23 MHz), and the operation of this clock is based critically on principles of quantum physics. If this frequency were to change even slightly, because the laws of quantum physics underlying the atomic clock are not understood correctly or change with time, this would wreak utter havoc on the GPS system — see [GPS2009].
  3. Both the GPS satellite system, as well as handheld GPS units (including GPS units now used in many cars), use a large amount of sophisticated custom-designed computer circuitry — memory chips, processor chips and clock controllers, that often press the state of the art of semiconductor design, because of the severe competitive pressure to deliver GPS-based devices at the best performance for the lowest price. These chips, like numerous others in our high-tech world, are designed based on the laws of quantum physics in a critical way. Thus if these laws are not understood clearly, or if they do not apply in certain exotic settings such as in outer space, or if they change gradually over time, then then it is possible that GPS devices would start to fail at some point.
  4. The GPS system also critically relies on Einstein’s relativity, both special relativity (the slowing down of clocks moving at very high speed) and general relativity (the slowing down of clocks in strong gravitational fields). Einstein himself initially doubted that anyone would ever be able to measure such effects. But in the GPS system, such effects are not only measurable, but indeed must be taken into account, or otherwise errors would quickly accumulate to the point that the system would be hopelessly inaccurate — see [GPS2009].
  5. The design of chips, and, for that matter, the original design of the GPS system itself, has relied on heavy-duty computations, in some cases using powerful supercomputers that have been designed specifically for scientific and engineering usage. These computations, in turn, rely on principles of applied mathematics and numerical analysis to ensure, for instance, that solutions converge to the true answers and that round-off errors do not threaten the integrity of the results. These principles, in turn, are encapsulated in large computer programs, often incorporating tens of thousands of lines of code, which employ advanced algorithms, data structures, and parallel programming constructs. And, as we all well know, computer programs often have “bugs,” in spite of the best efforts to remove them. In any event, quantum-physics-based computer codes are used for research in both pure and applied physics, and thus any serious difficulties uncovered in such codes might impact both the technology and our understanding of the physical laws.
  6. Finally, all of the above disciplines (quantum physics, relativity, electrical engineering and scientific computing) rely heavily on sophisticated mathematics. If some fundamental flaw were discovered in the edifice of modern mathematics, the entire structure of modern science and technology, certainly including GPS and even some aspects of geology and biology, would be drawn into question.

In spite of all these daunting obstacles, my latest “experiment” passed with flying colors — I found one geocache within six meters (roughly 20 feet) of the posted coordinates on the geocaching website, and I found another within three meters (roughly 10 feet) of the posted coordinates — both well within the specifications of GPS technology. In other words, even though the hikers who placed these geocaches measured their locations using a configuration of satellites completely different than those visible in the sky when I made my measurements, and even though each of these measurements relied on an long “symphony” of modern science and technology, and even though the GPS handheld units we used most likely were designed by different design teams and incorporated different hardware chips, somehow all of this “symphony” worked just fine.

This is dramatic confirmation that we understand the fundamental laws of physics very accurately. It is also confirmation that these laws do not appear to be changing significantly with the passage of time. The same GPS design specifications made in the 1960s and 1970s still work today, 40 years later. If there were even the slightest change in these underlying laws or physical constants, we might start seeing inexplicable errors in GPS positions. But we don’t.

In similar way, numerous experiments have been performed to see whether rates of radioactive decay change with heat, pressure or magnetic fields, but no variation has been noted for any of the isotopes used in geologic dating [Dalrymple2004, pg. 58-60]. Also, the spectral lines of light rays reaching the earth from distant stars, generated by atomic processes that occurred millions (or even billions) of years ago, exhibit the same frequency patterns that are predicted by the laws of quantum physics as we understand them today, and which we see confirmed in modern-day experiments [Barrow2007, pg. 124-128].

In short, the “pick and choose” approach to modern science simply does not work, and is certainly not recommended as a “solution” to the conflict some see between science and religion. Beyond a certain level, all of modern science is interconnected, and thus one cannot accept a large portion of modern science but reject another. If nothing else, such an approach is intellectually inconsistent — if one really believes that geology and biology should be rejected because radiometric dating (and thus modern physics) is not reliable, then one should avoid using any smartphone with GPS mapping capabilities (such as the new iPhones), since, as we have seen, at some level they are designed on the same physical principles as radiometric dating. But somehow I don’t think anyone will give up their iPhones just yet.


  1. [Barrow2007] John D. Barrow, New Theories of Everything, Oxford University Press, Oxford, UK, 2007.
  2. [Dalrymple2004] G. Brent Dalrymple, Ancient Earth, Ancient Skies: The Age of Earth and its Cosmic Surroundings, Stanford University Press, Stanford, CA, 2004.
  3. [GPS2009] “Global Positioning System,” Wikipedia article, 2009, available at
    Online article.

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