Sabine Hossenfelder in Scientific American:
This is not the right time for a bigger particle accelerator. But CERN, the European physics center based in Geneva, Switzerland, has plans—big plans. The biggest particle physics facility of the world, currently running the biggest particle collider in the world, has announced it aims to build an even bigger machine, as revealed in a press conference and release today.
With that, CERN has decided it wants to go ahead with the first step of a plan for the Future Circular Collider (FCC), hosted in a ring-shaped tunnel 100 kilometers, or a bit over 60 miles, in circumference. This machine could ultimately reach collision energies of 100 tera-electron-volts, about six times the collision energy of the currently operating Large Hadron Collider (LHC). By reaching unprecedentedly high energies, the new collider would allow the deepest look into the structure of matter yet, and offer the possibility of finding new particles.
Whether the full vision will come into existence is still unclear. But CERN has announced it is of “high priority” for the organization to take the first step on the way to the FCC: finding a suitable site for the tunnel and building a machine to collide electrons and positrons at energies similar to that of the LHC (which however uses protons on protons).