Man’s relentless thirst for knowledge sends him deep into the stars, but also deep within the microscopic particles that make up the universe, like protons and electrons. In this piece, we see how at CERN, the most fundamental questions are being answered by a simple technology like photography.
CERN is the world’s largest particle physics laboratory, located just outside Geneva in Switzerland. It is also home to the Large Hadron Collider (LHC), which has become a household name ever since the TV show Big Bang Theory became such a popular hit. The LHC is a 27-kilometer long circular tube through which elementary particles are sent hurtling, and their properties are studied by means of four detectors, which take snapshots of the particles as they go buzzing through the tube.
There is an experiment that is being constructed at CERN which looks at the properties of anti-matter and asks the question of whether anti-matter has the same physical response to gravity as does matter. In order to perform this experiment, scientists at CERN are using old film photography techniques to track the motion of anti-matter through the LHC. At the time of the Big Bang, equal amounts of matter and anti-matter appeared in the universe, but today, we find that all anti-matter has disappeared. This experiment tries to figure out why that is.
So in order to do this, they have to first start with creating an anti-hydrogen atom, tease out the anti-electron and anti-proton from the nucleus, and make them ‘fall’ to Earth’s gravitational force, so that their velocities and other parameters can be measured. The surface they fall on, or the wall they will hit, is not solid ground, but it is a photographic emulsion screen which is three-dimensional, like a blob of jelly into which the anti-particles will enter, and burst out when they collide with the copper and the bromide nuclei. While conventional photography uses a screen, this experiment uses a three-dimensional jelly which captures the ‘journey’ of the anti-particle as it enters and exits, leaving a trail behind it.
Particle physics is the most existential of all sciences, because it asks the fundamental question of life, such as who we are, where we have come from, and why we have come to be in this particular way. It’s wonderful that an old technology such as photography helps in uncovering new knowledge in this way.