This post is a repost of some proto-blogging I did on my department web page when I was a post-doc in Amsterdam. The web page is gone, now, so I thought I'd revise the essay significantly for the blog here.
I don't think it is too much of an unfair generalization to say that science and scientists are rather unappreciated in the United States. Folks are quite happy to reap the benefits of science and technology when it comes to their computers, iPhones, etc., but can be dismissive or indignant to scientists when their results show people truths that they are uncomfortable with, e.g. evolution and global warming.
That's not to say that other countries are necessarily much better, but I do occasionally run across pro-science efforts elsewhere that surprise me. From 2003-2004, I did my post-doctoral work at the Vrije Universiteit in Amsterdam, The Netherlands, an experience that I will count as one of the best times of my life. Amsterdam is just a wonderfully livable, walkable city, and even on my limited salary I was able to enjoy it immensely. While there, I kept up my figure skating training at the Jaap Eden Ijsbanen, which is located in the neighborhood of Watergraafsmeer outside of the city center. I would take the bus to the rink from my apartment, and every day would travel down Maxwellstraat and past Lorentzlaan, but it didn't occur to me until near the end of my time in The Netherlands that these streets are named after the physicists James Clerk Maxwell and Hendrik Antoon Lorentz!
In fact, all streets in the neighborhood of Watergraafsmeer are named after famous scientists and mathematicians, which is really a joy for a physicist like me. So after skating at the last day of the season at the Jaap Eden Ijsbanen, I decided to wander the neighborhood and hunt down the streets of those physicists whose work in the optical sciences has been a great influence on my own life's work, combining physics & travel blogging!
I present the streets in no particular order of chronology or significance; rather I present them in the order that I wandered past them. Information about the scientists themselves I gleaned from a variety of sources, including printed biographies, internet sites, and historical articles by my thesis advisor. Pictures of the various scientists were taken from Wikipedia. So without further ado, let us begin our tour -- feel free to follow along the trail via Google maps...
Johannes van der Waalsstraat
Okay, the first street I visited wasn't one of an optical scientist, but it was such a pretty street that I took a picture of it anyway!
Johannes van der Waals (1837-1923) was a Dutchman, born in the city of Leiden. He distinguished himself in the eyes of scientists with his 1873 doctoral thesis, "On the continuity of the gas and liquid state", in which he essentially provided a unified description of the gas and liquid states of matter. He won the 1910 Nobel prize in physics for his continuing research on this subject, "for his work on the equation of state for gases and liquids".
Most scientists are really familiar with van der Waals through the force named after him, the "van der Waals force", which is the attraction between neutral molecules that makes liquid water possible.
The section of street I photographed overlooks a nice park that is between the two directions of traffic on Radioweg:
Following Radioweg northwest to the magnificent park along Galileiplantsoen, I followed it southeast to a road named after another Dutchman:
Christophorus Buys-Ballot (1817-1890) was a Dutch meteorologist who made one lasting contribution to the study of optical sciences: the first experimental confirmation of the Doppler effect. In 1842, Christian Doppler (1803-1853) predicted that the frequency of light waves observed from a moving source depends on the motion of the source itself. The existence of this effect for light was not confirmed right away but in 1845 Buys-Ballot demonstrated the corresponding effect for sound waves with an ingenious experiment: he persuaded a group of trumpeters to ride on a fast moving train while playing a single note as loud as they could. Musically trained observers stationed on the side of the track noted the change in pitch of the note as the train whizzed past them, thus confirming Doppler's effect. Most people have inadvertently repeated this experiment themselves in modern times, listening to the pitch of a train horn change as it zips past them at a crossing.
In fact, the Doppler effect is so prevalent in modern times that it is difficult to imagine life without it: passing trains, cars, ambulances, motorcycles and aircraft can all demonstrate the phenomenon. In 1845, however, one would be lucky to get trains that could move over 20 mph, making the effect a small one and the use of observers with perfect pitch essential!
The idea of the Doppler effect is relatively simple to understand. A stationary object playing sound of a single frequency produces spherical waves with peaks that are equally spaced (to be drawn in red). When the source is moving, it ends up "chasing" the part of the wave traveling in the direction of motion, and "runs away" from the wave traveling in the opposite direction. The result is that an observer in front of the object sees wave peaks arrive much faster (higher frequency) and an observer behind the object sees wave peaks arrive much slower (lower frequency):
I photographed Buys-Ballotstraat from within the park at Galileiplantsoen:
Continuing down Galileiplantsoen, I cut southeast down Linnaeusparkweg to Fraunhoferstraat:
This rather quiet side road is named after Josef Fraunhofer (1787-1826), one of the scientists whose work greatly influences my own. Fraunhofer is known best to me as an author of several papers on the theory of diffraction, the theory of how light bends around corners and spreads out when squeezed through small holes. Fraunhofer's formulation of the diffraction problem still finds regular use today. Fraunhofer's career was given an unusual boost -- at the age of 14, the workshop in which he served as an apprentice glassmaker collapsed, trapping him under the wreckage. His rescue was supervised by the Prince Elector of Bavaria, a man who took a personal interest in Fraunhofer's work and provided him funding for his experimental researches.
One of Fraunhofer's other lasting optical legacies is his 1814 discovery and study of the absorption lines of the solar spectrum. Though sunlight is broadband light that contains all colors, Fraunhofer observed that certain specific colors were absent from the solar spectrum, and could be seen as dark lines when the spectrum is dispersed. Fraunhofer's original picture is shown below:
The upper plot represents the relative intensities of the various colors; sunlight is predominantly yellow. The lower colored figure shows the spectrum of colors as observed, with highly noticeable dark lines irregularly spaced throughout. Fraunhofer was not in fact the first to observe the dark lines of the sun; that honor goes to Wollaston in 1802. However, Fraunhofer performed the first systematic study of these lines, understanding which was later found to be the key to understanding atomic structure (more here). The dark lines in fact represent colors that are absorbed by the atoms that constitute the sun, and their locations are characteristic of the materials in question.
The view on Fraunhoferstraat; note the bike racks, which are omnipresent throughout The Netherlands:
At the end of Fraunhoferstraat, I turned southeast down Middenweg and followed it to the small but distinguished Christiaan Huygensplein:
Christiaan Huygens (1629-1695) is another of the giants of optical science, another Dutch scientist, and one of the greatest scientists of all time! Early in life he became adept at making telescopes and Huygens is credited with being the discoverer of Saturn's rings as well as its moon Titan. Most physicists know him best for championing the wave theory of light, which is in fact the foundation of ALL the work I do in theoretical optics. He published his findings in the book Traite de la Lumiere, published in 1690, in which he suggests that the propagation of a light wave can be described as every point on the wave producing a secondary spherical wave, each of which themselves propagate, a description now known at Huygens' principle. Huygens illustrated his principle quite beautifully in his book, showing the spherical waves emanating from a candle flame:
Huygens also invented the pendulum clock, revolutionizing the field of timekeeping, and developed the formulas that describe pendulum motion. He also introduced the concept of polarization to explain the phenomenon of double refraction.
On the other side of Huygensplein, we come to Helmholtzstraat, graced with an Albert Heijn grocery store:
Hermann von Helmholtz (1821-1894) is one of those rare scientists who worked in several completely disparate fields and was successful at all of them. He had studied medicine in Berlin and made important contributions to the physiology of the eye and of the ear (I have a copy of his book on the theory of sound in my office). In optics, he is well-known for the so-called Helmholtz equation (which I use in nearly all of my research), as well as one solution of said equation, the so-called Helmholtz-Kirchoff integral theorem, which is employed in the theory of diffraction mentioned earlier.
Incidentally, Niels Ryberg Finsen (who has the adjoining street to Helmholtz) has an optics connection as well: he won the 1903 Nobel Prize in Physiology or Medicine "in recognition of his contribution to the treatment of diseases, especially lupus vulgaris, with concentrated light radiation, whereby he has opened a new avenue for medical science".
I was getting pretty tired at this point in my optical journey, and began snapping some pictures of street names which I found pretty entertaining, not necessarily having to do with optics. I followed Helmholtzstraat to its end, and crossed Kruislaan to the next stop:
Nikola Tesla (1856-1943) is somewhat of a character in the world of science and invention. He was extremely prolific as an inventor (with over 700 patents) and extremely influential. He developed much of the technology that was later used in the development of alternating current. Though Tesla wasn't an optical engineer per se, he brought light to much of the world: his electrical technology was used was used to harness power at Niagra Falls in 1896, and was used by Westinghouse in lighting the 1893 World's Columbian Exposition in Chicago:
As important as his inventions were for civilization, Tesla is known just as much for his eccentricity and his strange and wild claims, such as his assertion of having communicated with other planets, and his claim of having invented a 'death ray'. He also completely dismissed the importance and validity of Einstein's relativity theory.
Tesla was infamously involved in a dispute over who invented the radio and held its first patents, himself or Marconi. In 1943 the U.S. Supreme Court decided that Tesla's patents held priority, a decision that seems justified. The court's decision may still have been somewhat biased, however, as Marconi was suing the government at that time for use of his own patents!
(Anyone else think Tesla looks a lot like Ralph Fiennes?)
Taking a long, long walk to the southwest along Kruislaan, I at last came to Maxwellstraat:
James Clerk Maxwell (1831-1879) formulated what may be considered one of the most important results in all of theoretical physics. In 1864 he formulated a set of equations that described all electric and magnetic phenomena known at that time. These so-called Maxwell's equations have solutions in the form of waves that travel at the speed of light, which allowed Maxwell to speculate that light is in fact an electromagnetic phenomena, an idea that was revolutionary at the time. The Maxwell equations are among the most exact equations in all of physics; in the 150 years since their introduction, no experiments have shown that there is anything wrong in Maxwell's original formulation (though the interpretation of this formulation has changed with the advent of quantum field theory).
Maxwellstraat is a relatively busy road with a healthy amount of traffic:
Off of MaxwellStraat there is a quiet little road that leads to a garden, and it is named after yet another great Dutch scientist:
This street is named after Hendrik Antoon Lorentz (1853-1928). He obtained his doctorate at the amazingly young age of 22 (I got mine at 29) and only three years later he was appointed to the Chair of Theoretical Physics at Leiden, which had been created especially for him. His scientific contributions are too numerous to mention in a paragraph, but he is known to me primarily for two results: a microscopic theory of light propagation through material media (the theory of dispersion) and the so-called Lorentz transformations, well-known in Einstein's special theory of relativity. Lorentz was another Nobel Prize winner, winning half of the 1902 Prize in Physics with Pieter Zeeman "in recognition of the extraordinary service they rendered by their researches into the influence of magnetism upon radiation phenomena".
It was at this point of my journey that I stumbled across a map of Watergraafsmeer, and found that Newtonstraat was pretty much on the other side of town from where I was! I sighed, stuffed my coat into my bag, and trudged a number of miles back to see the street named after Isaac Newton (1642-1727).
Newton hardly needs an introduction from me. He was one of the first to develop calculus, and he made many contributions to the theory of gravity, mechanics, and mathematics: pretty much everything a freshman physics major sees in class. He also wrote a classic text on optical phenomena, Opticks, which is still in print to this day and full of interesting insights. He was a strong proponent of the idea that light consisted of particles, not waves, and his views beat out those of Huygens for nearly a hundred years. (Each would later be shown to be half right - light has, in fact, both wave and particle-like properties). Newton was an unusual fellow: he spent a large portion of his life studying alchemy, and in his later years he fought crime as the warden of the Royal Mint!
What looks to be an elementary school lies at the end of Newtonstraat, appropriate considering the amount of enlightenment Newton brought into the world.
Galileiplantsoen, Johann Keplerstraat and Archimedesweg
Newton marked the end of my trip through the streets of optical scientists, but on the way out I snapped two final pictures. One was of a fysiotherapie shop named after Galileo off of a street named after him. Galileo Galilei (1564-1642) has been referred to as the "father of modern science", and with good reason. He made fundamental observations regarding the motion of objects under uniform acceleration, including the discovery that objects have the same acceleration under gravity regardless of weight. He also made fundamental improvements to early models of the telescope and was the first to observe Jupiter's largest moons. He was also arguably the first scientist to be persecuted by the religious powers-that-be for his beliefs -- he was brought before the Inquisition for supporting the Copernican view that the Sun, not the Earth, is the center of the universe. (As is always the case, though, the story is more complicated.)
It is rather appropriate that Galileiplantsoen intersects Johann Keplerstraat, as Johannes Kepler (1571-1630) was a contemporary of Galileo and also developed an improved telescope design and made fundamental astronomical observations. He is best known to physicists today as the codifier of laws of motion of the planets, now known as Kepler's laws, that would later be explained and reproduced by Newton in his law of universal gravitation.
He also was the first scientist to defend in print the heliocentric (Sun-centered) view of the solar system put forth by Copernicus. However, Kepler's initial attempt to quantify the Copernican system was rather... fanciful! He attempted to situate the positions of the planets on spheres that were inscribed inside/outside the various Platonic solids (cube, tetrahedron, etc.):
Archimedes (287-212 B.C.?) was a Greek scientist and mathematician who made many fundamental discoveries. In physics he is best remembered for Archimedes' Principle, which states that the buoyant force on a submerged object is equal to the weight of the fluid that is displaced by the object. A well-known story involves Archimedes uncovering fraud in the manufacture of a golden crown by use of this principle; legend has it that he realized the principle while in the bath, and ran excitedly naked through the streets declaring it! There is also an optical connection to Archimedes, though likely apocryphal: it is said that in the defense of the city of Syracuse, he used mirrors to focus sunlight onto enemy ships to set them aflame!
I hope you've enjoyed this whimsical simultaneous journey through physics/optics history and a neighborhood of Amsterdam! Are you aware of any other interesting and unusual tributes to scientists in the public sphere? Leave a comment and let me know!