CERN Accelerating science

Expanding our Horizons

Accelerating News, Issue #19 - Letter from the Editor


"The little prince was not able to reach any explanation of the use of a street lamp and a lamplighter, somewhere in the heavens, on a planet which had no people, and not one house. But he said to himself, nevertheless: "It may well be that this man is absurd. But he is not so absurd as the king, the conceited man, the businessman, and the tippler. For at least his work has some meaning. When he lights his street lamp, it is as if he brought one more star to life, or one flower. When he puts out his lamp, he sends the flower, or the star, to sleep. That is a beautiful occupation. And since it is beautiful, it is truly useful..."


- Chapter 14, The Little Prince,  Antoine de Saint-Exupéry

On 11 February 2016, David Reitze, executive director of the LIGO Laboratory, announced the first detection of gravitational waves. “It’s the first time the Universe has spoken to us in gravitational waves. This was a scientific moonshot and we did it. We landed on the Moon,” he said. He had every reason to be proud. In September 2015, the LIGO detectors had picked up a signal of two black holes that collided 1.3 billion light years away, sending shock waves across spacetime. Gravitational waves were first predicted by Albert Einstein a century ago as a consequence of his theory of general relativity, which unifies special relativity and Newton's law of universal gravitation to describe gravity.


Gravitational waves produced during the merge of two black holes have been detected by the LICO collaboration (Image credit: The SXS (Simulating eXtreme Spacetimes) Project)

This discovery comes a couple of years after ESA’s Planck satellite offered a detailed map of our Universe based on cosmic microwave background radiation (CMB); a major source of information used to piece together the history of our Universe. They constitute two important steps/advancements in modern cosmology. However, they both seem to confirm well established theories that were formulated in the course of the 20th century.  Gravitational waves was the long-awaited observable predicted by the theory of relativity while the results of the Planck mission confirm the standard cosmological picture of our Universe with ever greater accuracy. However these theories seem to leave many open questions not to mention the fact that the theory of relativity is not so far compatible with the theory of quantum-mechanics.

Looking to the field of high-energy physics, the discovery of the Higgs boson in 2012 at CERN came to conclude the long-standing effort to confirm the Standard model of particle physics. The ATLAS and CMS experiments at the Large Hadron Collider announced the discovery of a new particle in the mass region around 126 GeV, consistent with the properties of the Higgs boson that François Englert, Robert Brout and Peter Higgs proposed in 1964. The discovery of the Higgs boson confirms the existence of the Higgs field, a fundamental field that permeates our Universe and is responsible for giving elementary particles their mass.


The discovery of the Higgs boson  was undoubtedly the most astounding achievement in the recent history of physics.(Image credit: CERN)

The Higgs particle is often described as the cornerstone of the Standard Model of particle physics; a theory that attempted to describe experimental observations about the constituents of matter and reconcile them with the theoretical description of the forces through which they interact.

Both the Standard Model and general relativity, developed in the course of the 20th century, remain incomplete, leaving space for a number of unanswered questions. However, they are two of humanity’s robust attempts to describe and explain the world, attempts that began at the dawn of time when humans started observing and asking questions about nature.
Scientific endeavours are not limited to a global community of experts - often misleadingly portrayed in their white robes and sitting in their remote laboratories. On the contrary science has a social side and is foremost a human and community endeavour.
The effort to understand the world is also part of the formation of our identity and our feeling of belonging to a common humanity. We have travelled a great distance from the time of Democritus and his idea about for the existence of atoms to the development of the periodic table and more recently the formulation of quantum mechanics to describe the structure of matter at more fundamental scales.

Scientific leaps do not happen in the void; they are often closely linked to broader social changes, the reordering of political power, the emergence of new art movements, and fierce philosophical discussions. The history of science is full of comparable examples and offers valuable insights to the scientists of today. Scientific progress is not only influenced by social contexts, but also exerts great social influence. Breakthroughs such as the shift from the geocentric to the heliocentric system or, in more recent times, the discovery of the DNA sequence radically changed our understanding of the world and simultaneously had a deep social and cultural impact. One could also think the interplay between the study of the human genome and the development of gender studies and the birth of the web and how it changed the meaning of social participation, often empowering previously marginalized groups. Here we do not aim to offer an exhaustive discussion on the highly complex relation between scientific development and its socio-cultural implications, but offer a quick reminder that, as science is increasingly portrayed as a totally autonomous field, its interaction with other fields and its role in the formation of our human identity are sadly neglected.

Reflecting on the long history of scientific developments, one can see that certainties are rare and scientists often have to stand up to defend inconvenient truths or counter-intuitive facts. How uncomfortable scientists—not to mention the general public or funding agencies of the time—must have felt with the discussions on the existence of a new form of matter, the so-called antimatter, which was based on the mathematical solutions of the Dirac equation? How easily could physicists accommodate to Schrödinger’s uncertainty principle, which indicates that reality consists of a superposition of states that can exist with different probabilities. This is summarized in Schroedinger’s cat; a famous thought experiment that also introduced the key role of the observer. The early discussions that gave birth to the field of Quantum Mechanics offered certain inspiration but also valuable lessons for the future of fundamental physics. The list is endless and it is astonishing how far the scientific community has gone in adopting a new mindset - or a shift in scientific paradigm - that allowed some of the major breakthroughs but also important applications in our daily lives.

It is equally important to remember that the latest discoveries or theories that have widened our understanding of the world are not the final step in this journey of exploring the Universe. Whether radically new theories or more modest modifications are needed is something that remains to be seen and we have to be patient. Results from the LHC and cosmological experiments may shatter some of our past expectations. Moreover, future results of the LHC and other experiments -including non-accelerator experiments- may call for a fundamental change of scientific paradigm. We live in a period of turbulence of modern physics but we should not neglect that these have been the most fruitful periods in our field, presenting a number of challenges and new opportunities.

The results from the LHC - whether marked by a major discovery or not - are probably going to question our present understanding and some of the concepts that dominate the development of physics in the last decades. It is true that we enter in an era where we should remember the exploratory value of accelerators that can allow us to discover new phenomena. Science is not about offering certainties or confirming existing theories - no matter how attractive they seem - but about discovering the truth and gaining a deeper understanding on nature. As Professor Savas Dimopoulos notes: “Truth is both discovering new things and proving that some preconceptions, speculations, or theories are wrong. For example, the idea of the aether seemed plausible at a time, as it was logical to assume that electromagnetic waves need a medium, but it was disproved by the Michelson–Morley experiment. In this case, it was the non-discovery of something that created the big earthquake that led to relativity. Knowing what is false can be as important as knowing what is true.”

Today, fundamental physics is closely linked to humanity’s effort to explain the world and position itself in it. In that sense it has a profound impact on contemporary societies at a political, cultural, sociological, and ontological level. Modern experimental collaborations transcend national boundaries, a few physicists —Albert Einstein comes to mind— have achieved a celebrity status, and new discoveries make us reconsider our place in the Universe. Meanwhile, the machines we build to steal a glance at the great mysteries of nature, such as hadron colliders and particle detectors, celebrate humankind’s most admirable qualities: curiosity, persistence, and thirst for knowledge for the sake of knowledge, rather than for technological advancements it offers and the power and wealth that accompany them.

Outstanding questions in fundamental physics can only be successfully addressed through the variety of approaches that the global physics community has developed over the years.  We are possibly at the threshold of a new era in modern physics following the numerous observations from various fronts that seem to open more and more questions. This calls for considerable investment in new technologies and large-scale research infrastructures to offer new insights and allow to continue the scientific progress. As James Peebles, one of the pioneers of modern cosmology comments in the hand-in-hand development between fundamental physics and novel technologies: "Our understanding of nature has advanced in step with technological developments. The role of technology in the natural sciences, or curiosity-driven science is important. Astrophysics and HEP experiments that take place today thanks to the latest exciting advancements wouldn’t be possible few years ago. Of course technology is not the entire answer. Discoveries also need fresh ideas and concepts that can be tested either by developing new technologies or by finding new uses for old technologies”.

For many years, the development of larger and more powerful accelerators has been the way to address the open questions. One should not forget in the long course of the 21st century the role of accelerators in observing new phenomena that eventually led to a more fundamental understanding and thus a more accurate description of nature.
Accelerating particles to higher energies and colliding them (whether two beams or in fixed targets) brought a menagerie of strange elementary particles and gradually lead to the dominant theory of particle physics, the so-called Standard Model. 50 years' worth of subatomic specks churned out by accelerators and colliders filled key blanks, including the discovery of W and Z bosons in CERN’s SPS, the discovery of the top-quark the last missing quark of the S.M at Tevatron in Fermilab, the precise measurement of the S.M using CERN’s Large Electron Positron (LEP) back in the 90s and the confirmation that only three so-called families of particles exist and finally the discovery of the Higgs particle at the Large Hadron Collider (LHC). Without discussing in-detail the history of these discoveries one can see that extending the energy and intensity frontiers by developing the related technologies and building larger accelerators enabled a better understanding of our Universe. Yet many questions remain unanswered. The post-LHC era calls for a larger circular collider that would help the global scientific community to continue searching for answers to the open questions.. Extending the energy and intensity reach could give more precise measurements and provide access to new particles and phenomena.

The LHC and its High Luminosity upgrade (HL-LHC) guarantee the seamless continuation of the physics programme up to 2035. However, given the long lead-times involved in high-energy physics the community of worldwide physics community must start preparing the next accelerator for the post-LHC era now. It has taken more than thirty years to develop, build, and commission the LHC and this proves that we can’t afford to lose a second. The Future Circular Collider (FCC) study is one of the global efforts for thinking about future accelerators complementing existing technical designs for linear electron positron colliders (ILC and CLIC).

To build these machines calls for a coordinated effort to advance key technologies: high-field magnets, superconductors, novel materials, new vacuum systems and efficient cryogenics are some of the fronts where copious R&D efforts are invested and could find applications outside the field of fundamental research. .

The study for a future collider relies and builds on the valuable lessons of previous advancements in the field as well as from other international studies.The future of science lies in strengthening international collaboration while ambitious projects like FCC can have remarkable and unforeseen results. At the same time it is important to note that new concepts for future accelerators based on novel accelerating schemes are presently tested while it is equally important to think what we can learn from non-accelerator experiemnts that could compliment future large-scale research infrastructures.

All in all, the seemingly age of turbulence in modern physics calls for open mindedness in our approach to the fundamental theories but also for concentrated efforts in designing the scientific tools that will enable us continue this adventure. The latest findings from the LHC runs and future experiments in particle physics, Planck mission, LIGO and VIRGO, cosmology and astrophysics will challenge the way in which we do science and probably some of the concepts that have largely dominated in modern physics.
In that sense, we should not forget that science is not about certainties—a rather common misconception—nor about affirming existing theories, but rather about challenging dominant concepts and integrated stereotypes. This openness is an inextricable element of scientific progress. This is combined with curiosity; had Newton not wondered why an apple in Lincolnshire fell or Rutherford’s team in Manchester being less persistent, modern physics, and perhaps our lives, would be quite different. This quest for truth has shaped human history and identity across the millennia.

We are still confronted with questions related to the formation of matter, the domination of matter over antimater in our Universe (though we know from our experiments that they are equally produced), the dark matter content of our universe to mention but a few of the open puzzles. Searching for answers, calls for a coordinated effort in designing and developing the scientific instruments that will allow continuing the exploration - whether new accelerator or accelerator techniques, new telescopes or non-accelerator experiments. More importantly, it could call for a shift in the scientific paradigm similar to the one that took place in the beginning of the 20th century. New results from high-energy experiments or cosmological data may eventually prove that are just now start understanding the deeper structures that lie behind Quantum Mechanics and General Relativity; the two theories that shaped modern physics.


"That is a beautiful occupation. And since it is beautiful, it is truly useful..." (Image: Cannes Film Festival)

In conclusion, the history of physics teaches us that there is room both for the unseen and the unknown. We often tend to neglect that science is more about ambiguity and opening a space for questioning any certainty rather than about confirmation and reassurance. The scientific community in the next decades would most probably have to follow unchartered waters in order to expand our present horizons of knowledge. “Man cannot discover new oceans unless he has the courage to lose sight of the shore.” as Andre Gide’s famously noted.

Looking at the present physics landscape one can see an ocean of challenges and opportunities for physicists but also for engineers, innovators, early-stage researchers and for the future of our societies. Despite the possible lack clear evidence for the next big discovery we can’t afford to ignore the unanswered questions about our Universe and our understanding of nature. Perhaps we should remind ourselves the following words, coming from the Austrian physicist Erwin Schrödinger, one of the pioneers in the development of quantum mechanics: “The task is...not so much to see what no one has yet seen; but to think what nobody has yet thought, about that which everybody sees.”

I wish you the best for a creative and exciting new year.

Panos Charitos
Accelerating News, Editor in Chief