Sabine Hossenfelder in the New York Times:
The Large Hadron Collider is the world’s largest particle accelerator. It’s a 16-mile-long underground ring, located at CERN in Geneva, in which protons collide at almost the speed of light. With a $5 billion price tag and a $1 billion annual operation cost, the L.H.C. is the most expensive instrument ever built — and that’s even though it reuses the tunnel of an earlier collider.
The L.H.C. has collected data since September 2008. Last month, the second experimental run completed, and the collider will be shut down for the next two years for scheduled upgrades. With the L.H.C. on hiatus, particle physicists are already making plans to build an even larger collider. Last week, CERN unveiled plans to build an accelerator that is larger and far more powerful than the L.H.C. — and would cost over $10 billion.
I used to be a particle physicist. For my Ph.D. thesis, I did L.H.C. predictions, and while I have stopped working in the field, I still believe that slamming particles into one another is the most promising route to understanding what matter is made of and how it holds together. But $10 billion is a hefty price tag. And I’m not sure it’s worth it.