Fabiola Gionotti is an Italian particle physicist who holds one of the most important jobs in the scientific world. Gianotti is the director-general of CERN – European Organization for Nuclear Research. The name CERN is derived from the acronym for the French “Conseil Européen pour la Recherche Nucléaire”. In CERN, subatomic particles are smashed into each other at very high speeds with the hope of recreating the conditions of the big bang. Through the story of Fabiola Gionotti, we’ll explore the physics of motion.
Fabiola Gianotti was born in 1960 in Italy. From an early age, Gianotti was interested in nature and the world around her. Her father, an acclaimed geologist encouraged her early love of learning. Gianotti found her passion for scientific research after reading a biography on scientist, Marie Curie. Previously, she had studied the humanities, focusing on music and philosophy. Gianotti received a PhD in experimental particle physics from the University of Milan in 1989. Since 1996, following several postdoctoral positions, including a fellowship at CERN, she has been a research physicist in the Physics Department of CERN, the European Organization for Nuclear Research. CERN is the largest particle physics laboratory in the world. Gianotti is the director of CERN and works on the large hadron collider (LHC) where subatomic particles are smashed into each other to produce huge amounts of energy. The particles are travelling at enormous speeds, close to the speed of light around a 27 km circuit. In 2012 Gianotti announced the discovery of the Higgs boson particle. Until then, the Higgs boson was a theoretical part of the standard model in particle physics theory to explain how some fundamental particles acquire mass. Gianotti’s deep understanding of physics and her leadership were recognised as major factors in the discovery. All of these discoveries have been made possible by the motion of subatomic particles travelling at super high speeds around a circular track.
The physics of motion
In order to understand the physics of how things move, we need to start by defining some things. We are all aware of things like speed (how fast you’re going), distance (how far you’ve gone) and time (how long it took) but we will need a short formal definition of each of them, and their units.
Speed: The distance an object travels in one unit of time. Can also be called the rate of change of distance with respect to time. Unit: metre per second (m / s)
Distance: The length of space between two points. Unit: metre (m)
Time: A universal unit through which we measure events in the past, present and future. Unit: second (s).
Speed, distance and time are related to each other through the formula speed = distance / time. So if you want to know how fast something is travelling, you need to know what distance it has travelled and how long it takes to make the journey. If you know the speed of something, you can work out how far it will travel in a given time (distance = speed x time).
You may have heard of the term velocity, rather than speed to describe how fast something is going. It is usually heard in aeroplanes. Velocity is similar to speed but with one key difference – velocity includes the direction you are travelling in. So if we were to define velocity it would be:
Velocity: Speed in a given direction. Unit: metre per second (m / s)
Because velocity includes both speed and direction, it can be possible for something to have constant speed, but changing velocity. This is a bit of a head scratcher, but imagine one of the particles travelling along the large hadron collider in CERN. It will be travelling at a constant speed, but because it is moving in a circle, its direction is constantly changing. This means that its velocity is changing, although its speed is not.
When something speeds up or slows down, we say that it is accelerating. We can also say something is accelerating if its velocity changes (change in direction). The formal definition is:
Acceleration: The change in velocity over time. Or: The rate of change of velocity with respect to time. Unit: metre per second squared (m / s2)
We can understand the motion of almost everything in the universe if we know about its speed, velocity or acceleration.