Christiaan Huygens was one of the greatest Dutch scholars, if not the greatest. Versatility was his talent. Whether it was the invention of the pendulum clock, the discovery of Saturn's rings or the wave theory of light:virtually no area in seventeenth-century science was left without Huygens' discovery. Kennislink had a 'fictional interview' with the famous Dutchman.
His father called him his little Archimedes. It soon became clear that Christiaan Huygens (1629 – 1695) was a real child prodigy. At the age of nine he already spoke fluent Latin and composed his first piece of music. And at the age of seventeen, he was already taking part in the ongoing scientific discussions.
Mathematics would be central to Huygens' life. He continued the line initiated by Galileo Galilei:that the world around us is regulated by natural laws that you can describe with mathematics. Huygens was able to explain a whole series of natural phenomena with mathematical theories. In doing so, he shaped modern natural science. Kennislink imagined what it would be like to be able to speak to the famous scholar. Here you can read the result.
Dear Mr. Huygens, what an honor to speak with you. You are known as one of the greatest Dutch scholars. What do you think? “That pleases me. And I think it's right. I cannot deny that I have made significant contributions to science. I admit, modesty is not my forte. I have regularly been accused of appearing rather haughty and superior.”
Is that related to your upbringing? You come from a rich and distinguished environment. "That's right. My father, Constantijn Huygens, and my grandfather, Christiaan Huygens, were both secretary to the stadtholders in the Netherlands. Those were important political functions. My father also liked to propagate that, he felt elevated above the people.
I grew up in an intellectual environment. My father would have liked me to have gone into politics too. He sent Constantijn (his brother, one year older, ed.) and me to Leiden University in 1645 to study law.
However, I was more interested in the bit of math we were taking. This arose during lessons we received at home from our home teacher Jan Jansz Stampioen. In addition to Greek, Latin, music and geography, we learned math. Later we also got math. I found that I was proficient in that. During my studies in Leiden I became acquainted with the work of the French philosopher René Descartes. He regarded nature as a kind of machine, which you could describe with mathematical laws. That idea really appealed to me. After my studies I decided to dedicate my life completely to mathematical studies."
You had talent. I understand that at the age of seventeen you already undermined a mathematical proof of Galileo Galilei? "That's correct. Thanks to my father, I came into contact with Marin Mersenne, a French mathematician. He introduced me to the problem of a hanging rope suspended from two ends. According to Galileo, the rope has the shape of a parabola. I could prove that this is not so. Although I later discovered that also my solution faux wash.
Mersenne introduced me to more issues from that time. From him I learned that you shouldn't just be satisfied with what others had come up with. After my studies I started working on a number of geometric problems. For example, in the problem of determining the area of a circle, I was able to point out an error in the work of others. I published about it in 1651, my first writing. Looking back, I think these were mathematical trials that I took advantage of in my later work."
In 1655 you made two of your important discoveries, the moon and rings of Saturn. Tell me about that. “I calculated that it is best to use spherical lenses in a telescope and not, as Descartes thought, elliptical or hyperbolic lenses. I wanted to apply this in binoculars and started tinkering with them in 1652 and 1653. Lens sharpening turned out to be an art in itself. At the beginning of 1655, I and Constantijn had made a telescope about 12 feet (more than four meters, ed.) long that could magnify fifty times. When we looked at the sky, we initially thought we were seeing a star near Saturn. However, I followed its position for a few weeks and concluded that it must be a moon.
While studying the moon, I also focused on Saturn's "outstretched arms," which Galileo had previously observed. Since the arms remained the same all the time, the idea came to me that Saturn should be surrounded by a flat ring.
I kept both discoveries to myself for a while, until I was sure that I had studied all the details. To prevent anyone from getting ahead of me, I therefore sent a riddle to other scholars. I had hidden my discovery in this. So nobody knew about it, but afterwards I could prove that I was the first."
These discoveries came after you improved an instrument, a telescope, with mathematical insight. You did something like that again later, with the pendulum clock, didn't you? “Yes, that pleased me immensely:to systematically understand a device in detail, so that you can improve it. In my day, accurate and reliable clocks were needed, so that you could synchronize clocks in different places. That was also important for distance determination at sea. The existing clocks had a vertical axis that was turned alternately in one and the other direction, with the help of weights. But the weight affected the rotation speed, so as the weight dropped the clock became more inaccurate.
I had the idea to use a pendulum instead of the vertical axis, because a certain length of pendulum always moves back and forth at the same speed. I have studied the pendulum motion and the forces that play a role, such as gravity and centrifugal force. Thus I discovered that a pendulum has the same continuous movement when it follows a 'cycloid' orbit (the trajectory of an object in a rolling hoop, ed.).
I designed a new mechanism and had the pendulum clocks built by the Hague instrument maker Samuel Coster. This cooperation was not always pleasant, Coster sometimes thought that he could implement improvements on his own. Inappropriate for a simple instrument maker!
Fortunately, the timepieces turned out to be very accurate:they differed from each other only a few seconds per day. This result still fills me with pride. I fitted the towers of Scheveningen and Utrecht (the Dom) with clocks and received many orders, also from abroad. I sold my timepieces for 80 guilders, which was a considerable sum at the time. Still, I didn't think the timepieces were good enough:I spent the rest of my life trying to improve them."
You became famous and were able to work in Paris for a while, when you were a member of the French 'Académie Royale des Sciences'. A special honor for a Dutchman. Yet you were no longer welcome there in 1681, how come?
“I am still very outraged about that. I had been a member of the Académie since 1663, at the invitation of King Louis XIV. With this society of scientists we did a lot of work on lenses and pendulums. Unfortunately, I occasionally got sick and then went home to The Hague.
After I became ill in 1681 I suddenly did not have to come back. Was this how you interacted with someone from my rank? They say I didn't lead well or inspire others. Agree, I've had some conflicts with scientists, but it's hard for me to admit I'm wrong. It probably had to do with the fact that France and the Netherlands were at war."
You had a weak constitution. Still, being sick didn't stop you from working on new theories at home. Like your wave theory of light, Huygens' principle. “Is it called that in your time (it glows pleasantly, ed.)? I was prompted to think about the nature of light because of a new theory by the young Englishman Isaac Newton. He argued that light consisted of many colors and that each color had its own refractive index. So you could separate the colors with a prism. I was hoping to come up with a theory of light that would explain a strange kind of refraction I saw in an Icelandic crystal:you saw a double image when light fell on it.
I assumed that light is something that expands in space and thus has a certain speed. I was able to explain the strange refraction in the crystal by assuming that the light did not have the same speed in every direction.
Light is therefore not a straight line, but a collection of waves that spread over space. Just like the waves in a pool of water when you throw a pebble into it. Each piece of matter is a new light source from which light waves propagate. The total wavefront is the sum of the individual waves. With my wave theory I was able to derive the laws of refraction."
Newton was kind of a rival of yours. He had invented a reflecting telescope that was better than your binoculars. And he published his famous work, the Principia , in 1687 in which he expanded your mechanics. What did you think of Newton?
“That telescope of his was frustrating for me. Because of this, all the work I'd done to get rid of the colored edges of lenses had been in vain. But I also realized the consequences of his finding and appreciated that. His work, the Principia, was equally impressive. It was beautiful mathematics and his theories on the motion of bodies under the influence of a central force were awe-inspiring.
But the idea of him that bodies attracted each other was too crazy for me. The principle of attraction did not fit my mechanical view of nature. I've tried to mechanically describe the idea of gravity and even traveled to London to discuss it with Newton. Even though we differed, it was a pleasant meeting. I wrote down my ideas about gravity and published them, along with my wave theory of light, in the work Traité de la lumière in 1690. (his theory of gravity was later rejected, ed.)."
In addition to the aforementioned timepieces and viewers, you have designed many other things. And you even attempted science fiction. “I was interested in everything to do with technology and was easily distracted by new things. What have I designed again? A gunpowder engine, a vacuum pump, wind speed and barometers, a spirit level, a magic lantern – which my family especially loved – and even carriages I have ventured into. Also in the field of music, my great hobby, I couldn't resist. I designed a new harpsichord, which I could play pleasantly.
I don't know what you mean by "science fiction", that word is unfamiliar to me. But perhaps you are referring to my latest work on the universe, Cosmotheoros . I didn't know this was released! I speculated in it about other planets on which life could exist. In my view, the Earth was just one of the planets orbiting the Sun, so it seemed very unlikely to me that life would exist on Earth and none on the other planets."