The ancient Greeks believed that all matter consisted of tiny particles that could not be broken down further, which they called atomos, meaning indivisible. However, scientists had no evidence that atoms were in turn made up of smaller particles until the turn of the 20th century, when J. J. Thomson discovered the electron, which is responsible for electricity.

The field of particle physics was born and in the 1960s, theories were put forward suggesting that even tinier particles called quarks exist, which make up neutrons and protons. A Standard Model was developed to explain these particles, each with different properties and responsible for all of nature’s workings, from electromagnetism to radioactivity.

Deep underground in Geneva, Switzerland, lies the most powerful and precise instrument ever built by mankind to study the fundamental constituents of matter. The Cern Large Hadron Collider (LHC) is a 27-km-long circular particle accelerator, capable of accelerating particles to almost the speed of light and colliding them at high energies. It is a great feat of engineering and requires high-performance computing to process the equivalent of 210,000 DVDs worth of data it generates every day.

The Higgs boson, a fundamental particle, is predicted by the Standard Model as the reason why other particles have mass. It is extremely shortlived, meaning that only its by-products can be detected by the massive ATLAS and CMS experiments in the LHC. The Higgs boson is also very rare, occurring only once every 10 billion proton-proton collisions, and therefore the LHC took data for two years until sufficient results were in place to announce the discovery in 2012, a huge scientific achievement recognised by the Nobel Prize in Physics in 2013.

The Large Hadron Collider in Geneva, Switzerland.

The LHC has not rested on its laurels and a new type of particle, a pentaquark, thought to be produced naturally in the formation of neutron stars, was discovered by the LHCb experiment in 2015. The LHC will continue to take data, hoping to be able to ask questions related to dark matter, which does not absorb or emit light and makes up most of our universe.

Research at laboratories such as Cern resulted in several spin-offs: the World Wide Web was developed in 1989 to allow scientists to share their research, while touchscreens were invented at Cern in the 1970s for use in the accelerator control rooms. Perhaps one day, the superconducting technology used to generate magnetic fields bending particles around the LHC could be used in high-speed trains that hover over magnetic tracks for mass transportation.

The University of Malta is involved in several research collaborations in engineering, computing and physics with Cern, related to the LHC and the ALICE experiment. For more information, visit the website of the Particle Detector and Accelerator Research Group: http://www.um.edu.mt/research/pdarg

Gianluca Valentino is a post-doctoral fellow at Cern, supported by the COFUND Marie Sklodowska-Curie Action under the European Commission’s Horizon 2020 Programme.

Did you know…

• The hypothetical sterile neutrino does not interact via any of the fundamental interactions in the Standard Model except gravity.

• Last week, a weasel chewed on the wiring of an electrical facility at Cern’s LHC described in the main article. The result was a wide power outage with the whole facility going offline for a few days. The unfortunate mammal did not survive the incident.

• Sunlight takes about eight minutes and 17 seconds to travel the average distance from the surface of the sun to the earth.

• Speed of light is not constant. It varies, depending on the medium light passing through. Scientists slowed it down to just 38 miles per hour at absolute zero (-273.15C) through ultra-cooled rubidium.

For more trivia: www.um.edu.mt/think

Sound bites

• The idea that lightning never strikes the same place twice is one of the oldest and best known superstitions about lightning. There is no reason that lightning would not be able to strike the same place twice; if there is a thunderstorm in a given area, then objects and places which are more prominent or conductive (and therefore minimise distance) are more likely to be struck. For instance, lightning strikes the Empire State Building in New York City about 100 times per year.

• A penny dropped from the Empire State Building will not kill a person or crack the sidewalk. The terminal velocity of a falling penny is about 30–50 miles per hour (50–80 km/h), and the penny will not exceed that speed regardless of the height from which it is dropped. At that speed, its energy is not enough to penetrate a human skull or crack concrete, as demonstrated on an episode of Mythbusters.

https://en.wikipedia.org/wiki/List_of_common_misconceptions#Physics