CERN Proposes a $20 Billion Future Circular Collider to Hunt Unknown Particles

The European Organization for Nuclear Research (CERN) has formally proposed a massive new project: the Future Circular Collider. This $20 billion particle accelerator is designed to eventually replace the Large Hadron Collider. Physicists are outlining these plans to hunt for undiscovered particles and uncover the remaining secrets of the cosmos.

Unpacking the Future Circular Collider

The Future Circular Collider (FCC) is a proposed particle accelerator that will sit in a circular tunnel beneath the border of France and Switzerland. The physical scale of this project is staggering. The underground tunnel will measure approximately 91 kilometers (about 57 miles) in circumference.

To put this size into perspective, the current Large Hadron Collider (LHC) is only 27 kilometers around. The new facility will loop around the entire city of Geneva, passing deep beneath Lake Geneva and the nearby Alps.

The estimated cost for the first phase of this project is 15 billion Swiss francs, which translates to roughly $17 billion to $20 billion. CERN plans to secure this funding from its international member states, relying heavily on major financial contributors like Germany, the United Kingdom, and France.

A Two-Stage Scientific Master Plan

CERN plans to build and operate the Future Circular Collider in two distinct phases. This phased approach allows scientists to study different types of particle collisions over several decades.

Phase One: The Electron-Positron Collider

If approved, tunnel construction would begin in the early 2030s. The first collisions are scheduled to happen around 2045. This first machine is known as the FCC-ee. It will smash electrons and their antimatter counterparts, positrons, together at high speeds.

Physicists refer to this first phase as a “Higgs factory.” The primary goal is to produce millions of Higgs bosons in a highly controlled, clean environment. The Large Hadron Collider famously discovered the Higgs boson in 2012, but scientists need a better tool to study its properties. By measuring exactly how the Higgs boson interacts and decays, researchers hope to find subtle deviations from known physics equations.

Phase Two: The Proton-Proton Supercollider

The second phase, the FCC-hh, will not begin operations until the 2070s. This phase involves dismantling the electron-positron machine and installing a much more powerful proton accelerator inside the exact same 91-kilometer tunnel.

This supercollider will smash heavy protons together at collision energies of 100 teraelectronvolts (TeV). For direct comparison, the Large Hadron Collider operates at a maximum of 13.6 TeV. Pushing the energy limit to 100 TeV gives physicists the best mathematical chance of creating massive, undiscovered particles that currently exist only in theoretical models.

Why Physics Needs a New Accelerator

The Standard Model of particle physics is highly successful, but it is fundamentally incomplete. It only explains about 5 percent of the known universe. The rest consists of dark matter (27 percent) and dark energy (68 percent), two mysterious phenomena that remain completely invisible to our current scientific instruments.

Fabiola Gianotti, the Director-General of CERN, has stated that the FCC is the only proposed facility that allows the physics community to tackle these outstanding questions at the necessary energy scales. Scientists believe that dark matter must be made of actual particles. If these elusive particles interact with normal matter at all, the sheer force of the Future Circular Collider might be able to produce them in a laboratory setting.

Additionally, physicists hope to answer why the universe is made entirely of matter instead of antimatter. The Big Bang should have created exactly equal amounts of both, which would have instantly annihilated each other. The FCC will look for rare particle behaviors that might explain this cosmic imbalance.

Global Competition and Financial Hurdles

CERN is not the only organization planning a massive new accelerator. China has proposed its own massive project called the Circular Electron Positron Collider (CEPC). The Chinese proposal also involves a 100-kilometer underground ring but carries a lower estimated price tag of about $5 billion. This has sparked an intense global race to build the next generation of physics infrastructure.

Despite the excitement among researchers, the Future Circular Collider faces significant pushback. Funding a $20 billion science experiment requires massive political will. Critics point out that there is no absolute guarantee the FCC will actually find new particles.

Prominent theoretical physicist Sabine Hossenfelder has publicly argued that spending tens of billions of dollars on a larger collider is a poor investment for society. Critics suggest that funding should go toward more immediate scientific challenges, such as green energy technologies, or toward smaller physics experiments that do not require massive infrastructure costs.

CERN must complete a final, comprehensive feasibility study by 2025. After that study is reviewed, the 23 member nations will vote on whether to officially greenlight and fund the project.

Frequently Asked Questions

What will happen to the Large Hadron Collider? The Large Hadron Collider is currently undergoing a massive upgrade to become the High-Luminosity LHC. It will continue operating until approximately 2040. After that, it will likely be decommissioned to make way for the FCC, though its existing underground tunnels may be adapted to feed accelerated particles into the new, larger ring.

How deep will the Future Circular Collider be built? The tunnel will be built at an average depth of 200 meters (about 650 feet) underground. This specific depth is necessary to ensure the massive ring passes safely beneath local towns, natural waterways, and complex geological rock formations in the Geneva region.

What exactly is the Standard Model of particle physics? The Standard Model is the prevailing scientific theory that classifies all known elementary particles (like quarks, electrons, and the Higgs boson). It describes three of the four known fundamental forces in the universe: electromagnetism, the strong nuclear force, and the weak nuclear force. It notably does not include gravity or explain dark matter.