Europe’s Future Circular Collider Could Revolutionize Particle Physics—if It’s Ever Built

When I arrived astatine nan Fermi National Accelerator Laboratory (Fermilab) successful nan prairie suburbs westbound of Chicago to statesman my Ph.D., nan temper among galore physicists location still carried a quiet sadness.

Just a fewer years earlier, successful 1993, nan U.S. Congress had canceled nan Superconducting Super Collider (SSC), which would person been nan astir powerful particle accelerator ever built—an 83-kilometer subterranean edifice beneath nan plains of Texas that was designed to collide particles astatine astir 3 times nan power of what we execute coming astatine CERN’s Large Hadron Collider (LHC) adjacent Geneva. Construction had begun, and nan physics organization was live pinch anticipation. Then, abruptly, the SSC was gone—and pinch it, an opportunity to research a frontier that remains beyond our scope much than 3 decades later.

On May 22, 2026, successful Budapest, Hungary, nan CERN Council unanimously adopted an updated strategy, calling for the Future Circular Collider (FCC) to win nan LHC. This 91-kilometer ringing would tally beneath nan Swiss-French separator and would first big a precision electron-positron collider while preserving a way toward a proton collider that would run astatine much than doubly nan energies targeted for nan unrealized SSC.

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The FCC, arsenic presently envisioned, will require resources beyond CERN’s existent budget. The technological lawsuit is strong, nan method feasibility has been demonstrated, and nan organization has spoken pinch different clarity.

What remains is nan difficult task of turning that imagination into reality.

The Era of nan LHC

The consciousness of nonaccomplishment surrounding nan SSC lingered for years, particularly among elder physicists who understood its semipermanent consequences. But for young researchers for illustration me, nan organization still seemed afloat of life. Experiments were running, discoveries being made, and conferences hummed pinch caller ideas. Only later did I admit that nan cancellation of nan SSC had not conscionable halted 1 project; it had fractured nan semipermanent imagination for high-energy physics successful nan U.S.

In Europe, however, CERN followed a different trajectory: pursuing nan LHC. The LHC was not a consequence to nan SSC’s cancellation—the task was already past technically mature. But nan timing was telling: charismatic support of nan LHC came conscionable 14 months aft SSC was canceled. Fifteen years later, successful 2009, nan LHC began operation—a monumental effort that would specify nan adjacent era of discovery.

A position wrong CERN’s Building 40 successful Geneva, Switzerland, which is dressed up pinch a standard photograph of nan Compact Muon Solenoid (CMS) experiment. The CMS is 1 of 2 ample general-purpose particle physics detectors wrong CERN’s Large Hadron Collider, nan world’s largest and astir powerful particle accelerator.

Dean Mouhtaropoulos/Getty Images

Success was neither swift nor guaranteed; nan LHC faced superior guidance astatine CERN, pinch immoderate personnel states reluctant to perpetrate to a particle physics task of unprecedented standard and cost. But whereas nan SSC collapsed aft gathering pinch nan aforesaid resistance, CERN took it connected and built nan LHC. Making nan instrumentality a reality took years of speech and existent organization sacrifice—CERN had to shed astir 800 imperishable unit complete nan building play to sorb nan cost. Having mislaid its ain machine, nan U.S. chipped successful arsenic well, yet contributing astir half a cardinal dollars to nan project. The 2 colliders were nan aforesaid benignant of stake placed nether nan aforesaid benignant of pressure; what separated them was not nan physics but nan willingness to spot nan task through.

The SSC’s demise reshaped nan geopolitical scenery for generations and came astatine a important technological cost. Had nan SSC been completed, nan U.S. apt would person discovered the Higgs boson years earlier, and its higher-energy collisions mightiness person opened nan doorway to phenomena that stay beyond our scope to this day. Instead nan discovery of nan Higgs boson belonged to CERN. Colliding protons astatine record-setting energies of almost 14 trillion particle volts (TeV), nan LHC became nan world’s astir powerful collider and redrew nan representation of experimental particle physics.

The Higgs boson is nary specified world footnote; for decades, it was nan missing cornerstone of the Standard Model (SM), and its find astatine nan LHC confirmed a startling idea: that an invisible section fills nan universe, giving wide to basal particles. Without it, atoms, stars and life itself could not exist.

Yet nan SM still remains an incomplete explanation of nature. Its occurrence is each nan much bonzer because it describes an tremendous scope of phenomena pinch astonishing accuracy while still leaving immoderate of nan biggest questions astir nan beingness unanswered. The mentation cannot relationship for dark matter and offers nary mentation for why nan beingness is made almost wholly of matter alternatively than equal parts matter and antimatter.

The unanswered questions do not extremity there. The SM cannot explicate why nan basal particles person nan masses and relationship strengths that they do; astir 20 parameters must beryllium inserted by manus alternatively than derived from nan mentation itself. A deeper mentation would make specified features consequences of nan mentation alternatively than arbitrary inputs. Viewed this way, nan SM resembles nan periodic array earlier nan advent of quantum mechanics: a remarkably successful explanation of quality that nevertheless points to a deeper organizing rule still waiting to beryllium uncovered. The SM is not simply incomplete astatine its edges—it besides raises questions from within.

Throughout nan history of particle physics, advancement has often travel done nan find of caller particles and phenomena. The basal logic is straightforward: to create heavier particles, 1 needs much collision energy. This is what we telephone nan power frontier. But a deeper mentation request not uncover itself only done nonstop discovery. Even particles that are excessively dense for america to nutrient straight tin alter, ever truthful slightly, nan behaviour of those that we tin observe. Measuring known particles pinch precocious precision provides a 2nd way to discovery: nan precision frontier.

The Higgs illustrates why some approaches are needed. Discovering it required pushing nan power frontier; knowing it now demands making progressively precise measurements. And much than a decade into nan LHC era, neither frontier has travel adjacent to exhausting its potential. The absence of caller particles astatine nan LHC has not narrowed nan opportunity; it has told america wherever to look. And it has done truthful by pointing successful some directions astatine once—toward higher energies, wherever heavier states would beryllium produced, and toward higher precision, wherever their fingerprints would look successful nan particles we already have.

Following nan Frontier

As nan awesome colliders successful nan U.S. unopen down, overmuch of nan American collider organization carried its expertise to CERN, joining nan world effort astatine nan LHC. Others stayed successful nan U.S., turning toward neutrino physics, driven by nan find that these particles—once thought to beryllium massless—actually person a mini mass, a hint that thing basal is still missing.

A intelligence examines a conception of nan Large Hadron Collider’s beamline wrong a passageway heavy beneath nan Swiss-French separator during attraction activity connected July 19, 2013.

Fabrice Coffrini/AFP/Getty Images

My ain way has led maine to nan aforesaid crossroads. I near South America to study physics, earning my Ph.D. and completing postdoctoral training successful nan U.S., wherever I later became a professor. In 2011, arsenic Fermilab’s Tevatron unopen down and nan federation began to pivot distant from collider physics and toward neutrino research, I faced a choice: enactment successful nan U.S. aliases move to Europe, nan caller halfway of nan power frontier. I chose Europe, drawn by nan dream that collider-based particle physics would proceed to prosper here. Many others made nan aforesaid move, trusting that Europe still had nan determination to push guardant wherever others had stopped.

That dream rests connected coagulated ground. CERN coming is much than a physics laboratory—it is surviving impervious that nations tin build thing together that nary could build alone. Over nan past decades, its world footprint has efficaciously doubled, expanding to encompass 80 countries and much than 12,000 scientists from institutions astir nan world, alongside acquisition programs that train researchers astatine each level. Yet what has grown alongside these numbers is thing harder to quantify: a organization agreed astir shared questions, whose pursuit of basal knowledge has propelled technological invention and world practice guardant successful ways nary 1 anticipated.

The FCC would build connected this legacy.

From nan Higgs to nan Next Frontier

The roadworthy to nan FCC remains long, and Europe has been traversing it for years. Glimmers of that far-off extremity emerged successful 2013, erstwhile nan CERN Council launched nan first update of nan European Strategy for Particle Physics (ESPP)—a process designed to group nan guidance of nan section each 5 to 7 years done wide consultation pinch particle physicists worldwide. The study was unambiguous: Europe needed to beryllium successful a position to propose an eager post-LHC accelerator task astatine CERN by nan adjacent update. At that time, however, nan organization was not yet fresh to perpetrate to a circumstantial large-scale project. The statement was to attraction first connected upgrading nan LHC to summation its luminosity—the number of collisions per second—rather than instantly opening to build a successor.

Thus, nan High-Luminosity LHC (HL-LHC) came into being. Now nether construction, it is designed to present respective times much information than nan LHC, whose tally ended connected June 14, 2026. The HL-LHC will return complete astir 2030 and tally for astir a decade.

A 2020 update to nan ESPP marked a decisive shift, straight confronting nan mobility of what comes aft nan LHC. It reaffirmed nan HL-LHC arsenic nan apical near-term privilege but, for nan longer term, pointed unambiguously toward a hadron collider tin of reaching 100 TeV. That power lies acold beyond what foreseeable magnet exertion could execute successful nan existent LHC tunnel. The strategy, therefore, called for a new, larger tunnel, built to big nan programme successful 2 stages: first, a precision electron-positron collider to probe nan SM successful bonzer detail, past a hadron collider to widen nan power frontier. Each would prosecute physics that nan different could not.

Because these machines return decades to creation and build, nan determination must travel soon if nan adjacent collider is to statesman operations by nan mid-2040s. Delaying overmuch beyond that risks nan continuity that has sustained collider physics for generations. Particle physics will not disappear—its technological scope extends beyond colliders—but flagship projects anchor communities of scientists and engineers whose expertise is built complete decades and passed from 1 task to nan next. Without a clear way beyond nan HL-LHC, that concatenation becomes harder to maintain.

In 2025, CERN completed a broad feasibility study for nan FCC, marking an important milestone successful nan implementation of nan 2020 ESPP strategy. The study describes not conscionable a caller instrumentality but a decades-long programme of technological innovation—from nan exquisite beam power needed to make precision measurements of nan Higgs boson to nan improvement of superconducting magnets powerful capable to scope 100 TeV. Some of it has yet to beryllium invented—as is ever nan lawsuit astatine nan frontier.

The FCC feasibility study was only 1 constituent of a overmuch broader process of nan 2026 update to nan ESPP. The strategy process evaluated a wide scope of proposals, including linear electron-positron colliders, muon colliders, electron-proton facilities, and reuse of nan existing LHC tunnel. After astir 2 years, nan conclusion of this process was clear: nan FCC would connection nan strongest operation of technological reach, method readiness, and semipermanent strategical value. When nan CERN Council met successful Budapest successful May, it endorsed nan ESPP’s recommendations and group CERN connected nan way to preparing a connection for governments to measure by 2028. The mobility is nary longer what tin beryllium built. It is whether we are consenting to build it.

A representation showing nan preferred placement of CERN’s Future Circular Collider and its 91-kilometer-long subterranean ringing on nan Swiss-French border. The smaller ringing of nan Large Hadron Collider is shown for comparison.

CERN

Some encouraging signals propose nan will to adjacent nan backing spread whitethorn exist. In 2025, a consortium of private donors pledged $1 billion toward nan FCC’s construction, marking nan first clip successful CERN’s history that backstage philanthropy has committed to a flagship investigation task astatine this scale. And nan European Commission has signaled nan FCC’s strategical value to nan continent by including it among 11 projected “moonshots” successful its draught plans for awesome subject projects betwixt 2028 and 2034. And successful 2024, CERN and nan U.S. signed a associated connection of intent that expressed nan U.S.’s volition to collaborate connected nan FCC, should CERN personnel states prime it arsenic nan laboratory’s adjacent awesome facility.

Europe’s Choice

Today, CERN stands proudly astatine nan halfway of nan world particle physics enterprise. The work for taking nan adjacent measurement whitethorn remainder pinch Europe, but nan opportunity belongs to everyone who has ever wondered what nan beingness is made of and why it has nan building it does.

For decades, nan incremental way was nan correct one: upgrading existing facilities, extending timelines, squeezing much scope from nan tunnels we already had—each measurement returned existent physics, and nan HL-LHC will return more. But incrementalism is simply a strategy for erstwhile nan section is still deciding what to build next, and that is nary longer nan situation. We cognize now what nan adjacent instrumentality must do—push some frontiers successful turn—and nan section has identified a preferred way for doing so.

The questions that particle physics asks are thousands of years old. We person made them sharper and much sophisticated, but their quality is unchanged: What is nan world made of, and why does it person nan building it has? To extremity seeking answers is simply a prime to dim a ray that has guided quality enquiry for millennia.

My ain profession will apt extremity astir nan clip nan HL-LHC delivers its past collisions, a imaginable I see a privilege. I entered nan section successful nan protector of nan SSC, already knowing I would ne'er spot that power frontier. I will astir apt time off it nan aforesaid way—without having seen nan adjacent one. But what matters is not whether I spot it. What matters is that we support pursuing each that is worthy uncovering and that we build nan devices to find it, moreover knowing that nan uncovering whitethorn autumn to those who travel after. That belief—that nan beingness rewards curiosity—is what makes america not conscionable physicists but conscious participants successful 1 of humanity’s oldest endeavors: nan agelong effort to understand nan beingness we find ourselves in.

This is an sentiment and study article, and nan views expressed by nan writer aliases authors are not needfully those of Scientific American.