Chritiaaan Huygens (16291695)
Before talking about why Newton ranks higher than Huygens in physics, let us look at some photos of the House of the Huygens, known as Huygens’ Hofwijck, in Voorburg near Rotterdam. You know where Rotterdam is.
 This house was built by Christiaan's father named
Constantijn Huygens
who was a powerful politician. Based on
the items displayed in this house,
his family made their fortune from the trades with Indonesia. Those "flying Dutchmen"
imported spices from Southeast Asia. Black pepper was introduced to the Western
world at that time. Can you think of a dining table without pepper dispenser?
 In front of this house, there is a statue of Christiaan with his father.
I am sitting there
in this photo.
 This house is built upon a lake.
 This house looks like this from the Voorburg railway station. However, it is not possible to walk directly to the house. It is separated by a lake.
 You have to go though this road between the trees to enter the house ground.
 This is how the railway station appears from the
entrance to the House.
 The house door says
Huygens Museum Hofwijck.
Let us look at some of the precious items his family owned.
 One of the jewelry boxes. Here is another one.
 One of the book cases with rare items.
 Precious materials from Indonesia.
 Elegant fireplace. Here is another one.
 One of the old Dutch currencies carrying a portrait of Christiaan Huygens. They use Euros these days in the Netherlands.
 The most interesting items are the machines Huygens built to find out
physical laws.
 With this machine, Huygens proved the pendulum period does not depend on the mass. I did this experiment in 1949 when I was the firstyear middle school student. I am standing next to this machine in this photo.
 With this machine, he studied acceleration of falling bodies. He was of course interested in whether it depends on the mass.
 I was not able to spot rotating instrument to measure the centrifugal force. I am
still curious.
 Huygens was interested in the planetary system, with this figure, especially the rings of the saturn.
 I am not able to figure out what he was doing with this elegant gadget.
 He was interested in jumping from the sky with a parachute.
 He was also interested in chemistry. I did not know.
 Whatever he did, he described his observation mathematically and graphically.

Projector with a gaslight.

With this kind of environment, it is not possible to avoid the wave nature of everything.
 Did he build optical instruments indicating wave nature of light?
I was not able to spot any.
 This glass box includes a telescope.
 He built this projector with gas light.
There were no electric bulbs during his time. This projector does not
any hint of wave nature of light?
 How did he become interested in waves? His house is sounded by a serene water surface. If a bird drops a thing, the wave propagates with a circular front. It is safe to assume that this effect led him to the wave nature of light.
 Another reason: He did not like Newton's corpuscular nature of light. Newton did not get along with anyone.
 Did he say anything about the wavelength of the light wave. No. He died in 1695. More than one hundred years later, in 1801, Thomas Young (17731839) performed the first doubleslit experiment to measure the wavelength.

As far as I could see, Huygens spent most of energy to figure out mechanical aspects of this world. His formulas for pendulum and centrifugal force played pivotal role in the development of mechanics. Yet, Isaac Newton gets all the credits. The reason is very simple. He came with one formula that produces both formulas, and many more.

Isaac Newton. Nobody liked him during his time.
 The point is that physics is an art of synthesis. In addition to the two formula
by Huygens, Newton's equation synthesizes both elliptic orbits of planets and
hyperbolic orbits of comets.
 Maxwell's equations synthesize electricity and magnetism, leading the present world
of wireless world.

Einstein synthesized the energymomentum relations for massive and massless particles.
His formula is commonly known as E = mc^{2}.
 Werner Heisenberg gets the credit for synthesizing the particle nature and wave nature of matter.
 The point is that physics is an art of synthesis. In addition to the two formula
by Huygens, Newton's equation synthesizes both elliptic orbits of planets and
hyperbolic orbits of comets.
 The remaining question is whether we can find a single mathematical framework which
produces both quantum mechanics and special relativity. Don't worry. I am not the first
person to ask this question.
 When I was at the Niels Bohr Institute in Copenhagen in 2015, I noted Einstein
visited the place occasionally. I asked a young man there whether there has been
any effort to synthesize quantum mechanics and special relativity. He
said "Dirac," and ran away. I thought I was a hopeless old man asking a hopeless
question, and he did not want to waste any more seconds with me.
 He was right in mentioning Dirac. He was also right in regarding me as
a hopeless man, because he could not make money or get promotions by worrying
about this problem. However, I am different. I do not have to worry about
promotions, and my economic base is stable.
 Furthermore, he did not know I met Dirac in 1962, and became converted
like
Nicodemus after meeting Jesus (story in the Gospel of John). Since then
I wrote my papers mostly on this Dirac issue.
 Yes, I published many papers on squeezed states of light, and developed one
of the major conferences in quantum optics. What does this have to do with
Dirac?
The answer in very simple. Dirac was the first one to worry two oscillator states (or twophoton states) in his 1963 paper. I met him right after he completed this paper and submitted it to the Journal of Mathematical Physics. Click here for the story.
I like this machine, and
I like Dirac.
Photo taken at the Fine Hall Libray
of Princeton University (2000).  The harmonic oscillator is the language of quantum mechanics. According to
Dirac, two coupled oscillators produce the symmetry of the Lorentz
group applicable to three spacelike dimensions and two timelike dimensions.
If one of the those two timelike coordinates is contracted as the Lorentz group contracted group to Galilei group (Inonu and Wigner, the twooscillator system produces the symmetry of the inhomogeneous Lorentz group. Again, according to Dirac's 1949 paper entitled Forms of Relativistic Dynamics, the Lie algebra of the ionospheres Lorentz group is extension of Heisenberg's Poisson brackets to the Lorentzcovariant world.

Niels Bohr Institute in Copenhagen.
Dirac and Heisenberg (1030s).
 When I was at the Niels Bohr Institute in Copenhagen in 2015, I noted Einstein
visited the place occasionally. I asked a young man there whether there has been
any effort to synthesize quantum mechanics and special relativity. He
said "Dirac," and ran away. I thought I was a hopeless old man asking a hopeless
question, and he did not want to waste any more seconds with me.
 Paul A. M. Dirac published many great papers. His papers are like poems, but they
do not contain figures or diagrams. Another serious problem is that he seldom
quotes his own earlier papers. It is thus fun to fill in these gaps.
This has been my major business for many years.
You may click here
for my latest published paper on this subject. I hope to write more
papers along this line. Here is my ultimate wisdom.
`



The photo of Dirac and Heisenberg is from the AIP Emilio Segre Visual Archives.