Seeing and Believing as a Scientist
Compact Muon Solenoid detector. Photo credit: CERN
by Greg Rakness
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from LF Spring 2017
I am an experimental particle physicist, working as the Run Coordinator of the Compact Muon Solenoid experiment in the Large Hadron Collider located at the CERN laboratory (an acronym of the original French name, Conseil Européen pour la Recherche Nucléaire) in the picturesque countryside just outside of Geneva, Switzerland. I am responsible for the operation of one of the largest experiments in the world: a fourteen-ton detector with one hundred million channels of readout to detect proton collisions at a rate of forty million times per second. We perform precision experiments to test the theoretical predictions of a model that quantitatively describes the interaction of subatomic particles. Precision experiments, particles, quantification, and theoretical models—my workweek sounds rather cold and calculating. And on Sunday mornings, I go to church.
Some number of years ago a cousin asked me,“How can you call yourselfa ‘scientist’ and still believein God?” What follows is how I have come to reconcile the potentially conflicting points of view withinmyself, a hard-nosed scientist who also believes in an all-powerful creator. What I have to say is not particularly deep. And given that my theological training goes barely beyond Luther’s Small Catechism, there are probably holes in the religious part. Moreover, given that I am an experimental physicist whose specialty is making detectors work, the theoretical physics stuff may also be not quite right. But it’s worth the try. Here we go.
A Method of Disproving
Over the past century, an extensive set of observations has led to a precise, quantitative, and nearly complete model of how the physical world operates. With the wealth of data at hand and the advanced state of the model, the theory is most effectively and economically studied with a deductive approach using the “scientific method.”
The scientific method is a technique whose most effective use is to disprove a theory. The physicist starts by assuming that a particular theory is true and then uses that theory to make a prediction specific enough to be tested by a controlled experiment. The point of the controlled experiment is to avoid nuances in the outcome. If the results of the experiment are not consistent with the prediction of the theory, then we can conclusively state that the theory is incorrect. If, however, the results are consistent, the experiment is said to “support” the theory.
For example, we observe that objects fall down. The theory for this action was developed by Newton: objects fall down because of gravitational attraction to the earth. One prediction of Newton’s theory was that all things would fall at the same rate of speed, regardless of their mass. On this basis, we can perform a controlled experiment by dropping two things of different mass at the same time, like a hammer and a rugby ball. Result: they hit the ground at the same time. The experiment is consistent with the prediction of the theory!Note well that the experiment does not say that the theory is true, the be-all and end-all of the question at hand. The experiment says that the theory is not incorrect in this aspect. If instead the rugby ball were to hit the ground first, it would mean that Newton’s theory was wrong. A result that is inconsistent with the theory leads to a much, much stronger statement.
The scientific method is an extremely powerful way to make progress in physics. However, the astute reader will quickly realize that nowhere in the previous paragraph is there an attempt to explain why there is gravity. It is not a question to which we can apply the scientific method. Along the same lines, there are lots of questions that cannot be addressed well by the scientific method. Is there a God? How do I love my neighbor? How do we resolve a conflict? The scientific method is very powerful but it is also very limited. Most questions people ask are not actually good questions for scientists to test and try to answer.
Quarks, Leptons, Gluons, and Photons
Science has come to a precise, quantitative, and nearly complete model of how the physical world operates. This model has had such amazing success that it is now known as the “Standard Model.” The name reflects its success: it is the model that nearly all modern-day experiments strive to test—that is to say, to disprove. The Standard Model quantitatively describes the interaction of matter like this: a particle interacts with another particle by exchanging yet another particle.
These particles are “quanta,” which means they cannot be broken down any further. They are the objects that comprise all of nature, having such exotic names as quarks, leptons, gluons, and photons. The mathematics and rules of their exchange is thus called “quantum mechanics.” To add yet more mystique to the name, it has been observed that their exchange is governed by Einstein’s theory of relativity—the speed of light is the fastest things can go—so the mathematics is also called “relativistic quantum mechanics.”
Quantum mechanics describes an experiment that takes place in three steps: the initial state, the reaction, and the final state. It starts with a well-defined initial state—a proton beam of a given energy enters the target from a certain direction. The next step is the intermediate state in which the reaction happens. At this stage, the final products haven’t been seen yet, and therefore the “wavefunction” that describes this reaction simultaneously occupies all possible states. At the final state, the reaction products can be detected as the “collapse of the wavefunction” into a well-defined final state.
What wondrous words to describe the working of the microscopic world! And you put billions and billions of these particles together and what do you get? Flowers. A mountain stream. Music in your ears. The spontaneous laughter of a child. As much as I appreciate these things visible and audible to our human senses, over the years I have grown to appreciate them even more in realizing that they are all comprised of quarks and gluons whose exchange is quantitatively governed by relativistic quantum mechanics.
Asymmetry All the Way Down
A symmetry in experimental physics means that the result of an experiment is the same, regardless of the point of view of the observer. For example, when a ball hits the wall, the result is that it bounces back from the wall toward you. If you were standing on the other side of the wall, that same ball would still bounce back from the wall, but this time it would bounce away from you. However, the result is the same: the ball bounces back from the wall. The fact that the interaction is the same, irrespective of your point of view, is a symmetry.
Although it seems a bit esoteric, the net result of these kind of symmetries is to highly constrain the math used in the Standard Model. As it turns out, one of these symmetries is that all particles are massless—they have zero mass. However, we know particles do actually have mass. This causes a problem for the theory! The way around it is explicitly to include into the theory a mechanism to break the symmetry and give particles mass while preserving all the other symmetries. This is (a much too simple way to describe what is) known as the Higgs mechanism.
To return from subatomic physics to everyday reality, we are all keenly aware of brokenness being an integral part of life. We experience it every time we eat the bread in communion, or describe Jesus on the cross, or think of our situation as sinners. However, as I see it, this brokenness extends further, fractally, to the subatomic realm where the Standard Model rules: a highly symmetric theory with built-in symmetry-breaking.
Those with Eyes to See
One time I gave a seminar at Valparaiso University where we discussed what happens when an experimental physicist looks at a yellow flower. Standing at a distance, it is a beautiful yellow flower in a mountain meadow. Get a lot closer, and now all you see is the yellow. What exactly are you seeing?
Sunlight is a mixture of all the colors in the spectrum: red, orange, yellow, green, blue, indigo, violet. The color of the light is indicative of its energy according to its position in the rainbow: blue light is more energetic than red light. So when the sunlight hits the flower, most colors are absorbed except for the yellow light, which is re-emitted and detected by our eye. The reason that the flower re-emits the yellow light is because the molecules that make up the flower have an energetic structure that resonates with the energy corresponding to yellow light. You’ve gone from flower to molecules.
If you keep increasing the energy of the light shining on the flower, eventually you reach the point where you begin to resolve the energetic structure of the nuclei of the atoms that make up the flower. Now when you “look” at the flower, you no longer see even the molecules—you see atomic nuclei. If you increase the energy further, eventually you start to see the quarks and gluons. At this point your object doesn’t look anything like a flower, at all!
In physics, as in life, what you see depends on how you look at it.
How can I be a scientist who believes? In these ways. I acknowledge that most questions can’t be answered by science. I recognize and admire the beauty of the subatomic realm. I realize that meaningful concepts recur at all levels of existence. I see new things when I look at them in new ways.
Am I right? I have no idea. It does not matter.
As a scientist, I have the privilege to study God’s world in quantitative detail. As a scientist, I am obligated to do all I can to study the Standard Model, and as a Christian, I do it in praise of the Ultimate. I like to imagine that when scientists manage to discover some new little aspect or tiny feature of the created world, God says, “Good job, little researcher! Keep exploring. Just wait until you see what’s in store around the corner!”
I believe in the creator of heaven and earth, of all that is complex and simple. Bigger than my box. Ready to face the scientific method and any other question we bring to the table. Sing to the Lord a new song!
Greg Rakness is Run Coordinator of the Compact Muon Solenoid experiment at CERN in Geneva, Switzerland.
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