While it is one project it also is an umbrella to fund a large number of smaller projects. Whole institutes were funded and build in part to develop detector components for the LHC. A project like this gives everyone a common goal and pushes technology development in sectors that are critical to Europe's high tech economy. It also has consequences for the IT sector in Europe. Before cloud companies had to deal with PetaBytes of data, scientists at CERN and elsewhere developed techniques for filtering, storing and analysing this data with sophisticated statistical tools (and machine learning). You can easily scale your analysis run to thousands of machines all over the world and transparently get access to the huge experiment datastore.

There is no other scientific field in Europe that has developed a similar level of sophistication and scale. The initial idea behind the Human Brain Project was to build a similar infrastructure for Neuroscience research. But instead of the cooperation in Particle Physics it resulted in fierce opposition, out of fear that funding would be shifted away from national funding agencies and independent researchers and doubts over the ambitious goals of the project. If you think about it a project like CERN, that successfully contributed to understanding of the fundamental forces of nature is in some ways much more ambitious than a centralised program to understand the Human brain.

But the latter got badly derailed multiple times simply because the participants did not have the single minded will, focus and consensus that the Particle Physics community has been able to maintain for almost 70 years now.

> it also is an umbrella to fund a large number of smaller projects

Then justify the spending on those merits. Spending for the sake of spending isn’t a great argument.

Why is a new supercollider a better use of resources than, say, a new telescope? Or a suite of gravitational wave or neutrino detectors? A host of fusion research reactors?

The opportunity cost of spending shouldn’t be ignored just because it isn’t entirely useless.

It's not either or. E.g. ITER cost more than LHC, and the successor to ITER is in the works with construction expected to start years before this new collider would.

$23bn is a lot of money, but it also is a pittance when you're planning a project that will take ~30 years to be operational. E.g. for comparison the EU is planning ~$100bn for its science programs for the next 7 years; on top of that all the member states have their own projects, and non-EU European states have their own science funding.

As such, we're talking low single digits percent of overall European science funding, but even so CERN may not be able to fund $23bn from their own funding alone, and may seek out international sources of funding for this project.

It's really not low single digit. Firstly it's a proposal for ~€100bn (not ~$100bn), the current program is ~€80bn. Secondly if you look at the spending[1] more than 50% of it by any reasonable measure is "soft" science funding (such as reinvesting in high-tech industry).

I'm happy CERN is doing it's thing, but let's not hide the ball here, any way you look at it it's a huge portion of the EU's fundamental science research budget.

1. https://www.fch.europa.eu/sites/default/files/Horizon%20Euro...

> Firstly it's a proposal for ~€100bn (not ~$100bn), the current program is ~€80bn.

€100bn is $113bn; ~€80bn is $90bn.

$100bn is close enough.

> It's really not low single digit.

EU budget != European science funding. The $100bn number was used to illustrate that the amount is not that huge, with the addition that "on top of that all the member states have their own projects, and non-EU European states have their own science funding."

As I pointed out elsewhere, e.g. Norway, which is one of the 23 CERN members but not an EU member, has an annual R&D budget of $6bn. Over the roughly 30 year period of this project, that's $180bn.

Even if you assume half of that is what you consider "soft" funding (quite likely), Norway alone could fund all of CERN and this new collider (of course that would devastate Norway's other science programs).

As it stands, Norway's contribution to CERN is about $30m/year, which adds up to the highest per capita contribution of any CERN member. The UK for example pays less than half as much per capita.

It is overall likely (I haven't checked) that CERN adds up to less than a single percent of the science budgets of its member states alone. The CERN member states make up less than half of European countries (though most of the biggest and richest), so it's fairly safe to assume it takes up less than a percent of overall European science funding.

> [...]it's fairly safe to assume it takes up less than a percent of overall European science funding.

No it's not. We're in a thread where the cost of the LHC and its successors is being contrasted against funding for other comparable fundamental research, such as gravitational wave or neutrino detectors etc. Or other projects anyone might reasonably classify as fundamental research.

You're conflating that with R&D budgets. Let's take your example of Norway. 50% of its R&D budget is goes to industry, and 50% of that to the service industry. I'm going to go out on a limb and say that nobody in Norway's service industry is going to be getting a Nobel any time soon.

Due to how state subsidies are regulated in the EU's single market (and Norway, Iceland etc. count here too, they're in it through the EEA) R&D has become a backdoor for state subsidies. A supermarket paying a consultant to improve their billing system can be doing "research" and get a tax write-off or a state grant.

So you really shouldn't assume that you can conflate R&D in the EU's twisted definition with what is commonly understood to be R&D.

Now, back to Norway's numbers. In [1] you can see that around 20% of that $6bn goes to institutes, and around page 20 or so in [2] you can see where all this money goes.

Without going into a lot of detail I think it's fair to say the overall budget is mostly irrelevant to what we're discussing here. I'll let the fact that as [2] shows the industrial sector gets 50% of the funding but produces 2% of the scientific publications speak for itself.

Once you tease all this apart you'll find that by any sane definition the LHC and its successor project eat up a huge amount of the money that's spend on fundamental research of the sort that might yield a Nobel price any other measure you might use as a proxy for a fundamental new discovery in science.

And of course even the LHC/FCC blurs the line between the two. If CERN could spend that same money on more whiteboards and chalk for physicists and get the same results it would never be funded. The real purpose of the project includes being a subsidy for Europe's high-tech industries.

Once you peel back the curtains on how any of these projects are run you'll find that member states that kick in some % of funding expect and mandate that approximately that % works its way back to them in one way or another. In "The Large Hadron Collider: A Marvel of Technology" by Lyndon R. Evans it's mentioned that the initial construction plan for the LHC was rejected by member states since it didn't do a good enough job of spreading the pork around.

1. https://webcache.googleusercontent.com/search?q=cache:YRYPqQ...

2. https://www.forskningsradet.no/contentassets/8f25adbfd4cb437...

Because sometimes it is better to keep a large number of people occupied with one specific goal instead of trying to convince them to do something else. This ultimately boils down to people, most of them are very smart and capable and could do any number of other things, but basically want to work on fundamental particle physics. You couldn't easily convince them to build a telescope instead (a totally different set of people finds that fascinating) or any of the other things you listed. Besides there are (smaller) collaborations that work on all of these other things you mentioned as well.

Furthermore there is good motivation to keep nuclear / particle physics research as centrally organised as possible because the people working on it would be equally capable of producing nuclear weapons. For example a good number of the people working with CERN in France sit right across the Institute that developed their nuclear weapons.

I dont think the idea is to keep these particle physicists occupied. I think the idea is to fund other underfunded areas of physics while the particle physicists keep playing with the LHC.

> That same money could possibly be pumped into more immediately useful "hard" applied problems like fusion reactors

Interesting, I just checked the number for ITER (i.e: Europe's main fusion project), the project has been estimated at around €20-30 billion (with some pessimistic estimates from the US at around €60 billion for the completion of the reactor). And that's considered a VERY HIGH cost and has been the main concern from participating countries. But somehow $23 billion for a new collider have been approved?

Edit: correction, $23 billion haven't been approved, the plans for a potential collider, estimated at $23 billion, have been approved.

Think of CERN more as a cultural endeavor. It's the big, permanent, multigenerational physicists jamboree. The big colliders are not the goal, they are merely the foundation. The meat is in the detectors and experiments that are attached and that would not be possible elsewhere. Sure, the flagship experiments are also important in their own right, but their function as a rallying point, as a halo product for everything else that is happening there is a big reason why they should be funded.

A reactor project is a much less colorful affair, focused on a single deliverable. More contractors, less postgrads. There should be money for both.

ITER is just a demonstration system, it will hopefully produce a modest energy surplus. As just one step towards an actual useful fusion energy source, Its a proof of concept and it's cost need to be considered in the context of the whole endeavour.

The new collider will be a fully functional 'production' system that we fully expect to probe new physics, and test specific scenarios that will require it's particular capabilities. It's an end product and the latest in a highly successful, proven series of systems. By itself that doesn't make it worthwhile, but I think a high cost for a final system is a different beast from a high cost from a test project.

ITER's successor, DEMO is in planning, with a similar planned timeframe as this new collider... If we wanted to assign them to "generations", ITER should be compared against LHC.

ITER is considered very expensive exactly because nobody wants to spend all their money on one type of project, but in fact are concerned about ensuring their science funding is well rounded.

In an ideal world, both happens at the same time. Applied physics require fundamental research. It's impossible to say what will come out of it, but most of today's technologies comes from research that allowed us to understand our environment. Fundamental research takes time, maybe this project will allow future generations to solve problems they are facing.

Meanwhile, US's DOD budget in 2020 is 718 billion dollars.. So yeah..

The fact that a huge amount of money is wasted in one area doesn't justify wasting a smaller amount somewhere else.

But it puts things into perspective. Humanity blows crazy amounts of money on war, entertainment, advertising and the financial industry, within a system where something like two dozen individuals can (collectively) amass trillions of dollars of personal wealth. But $20 billion for fundamental science, spread out among 23 comparatively wealthy nations is too much?

To expand on your point to illustrate how relatively little this is:

Norway alone spends about $6bn on research and development a year for a population of ~5m people... This project will take ~30 years to complete. Norway alone could fund it.

But there's as you say 23 members (and more associate members), and as a CERN member, Norway contributes ~$30m/year to CERN. That's 0.5% of the R&D budget, or about $6/year per person.

This is the highest per capita amount of any CERN member, since funding is determined based on GDP. E.g. the UK pays less than half as much per capita as Norway. As such, it's reasonable to assume that for most members of CERN, funding to CERN takes up less than a percent of their R&D budgets.

It is likely member states would have to pay more for this, but amortized over the project period, we're talking at most double even without an international (beyond the member states) consortium.

And of course it's not only the 23 member states that benefits from this. Overall in terms of worldwide science funding, CERN is a rounding error.

That isn't relevant. CERN isn't a US government project and the US doesn't provide funding. The cumulative budgets of the EDA member states €223 billion in 2018[1].

[1] https://www.eda.europa.eu/docs/default-source/brochures/eda-...

> CERN isn't a US government project and the US doesn't provide funding.

That's news to US taxpayers, which have provided money to CERN projects for decades, including LHC. Half a billion dollars for LHC was considered a lot of money back in 1997 (when US GDP was ~37% the size it was in 2019).

2008: "On Monday, the Department of Energy and the National Science Foundation announced that the United States has completed - on budget and ahead of the September 30, 2008 milestone - its contribution to the Large Hadron Collider (LHC). Under its agreement with CERN, the U.S. contributed $531 million of accelerator components and particle detectors for the LHC."

https://www.aip.org/fyi/2008/us-contribution-lhc-budget-and-...

The US's contributions to CERN are equipment and services rather than money, but indeed they are a big contributor. They are certainly the largest participating country in the LHC by number of scientists.

The US isn't on here:

https://en.wikipedia.org/wiki/CERN#Member_states_and_budget

Cern is European, the counterpart in the US are fermilab, they are highly knitted together.

Protontherapy alone is enough justification in my opinion. Add the many kinds of detector offshoots that find their way to industry. The web itself, if you wanna go back a bit further. Aren't those worth it you think?

How is proton therapy a justification? The protons in PT have energies six orders of magnitude below that of this proposed FCC. Are you saying that the historical precedent of PT means FCC will also have that sort of spinoff? That's not a legitimate argument.

The top energy of the accelerator might not be a good judge of how practical its technology will turn out to be. The maximum center-of-mass energy of CLIC is 3 TeV [1], far in excess of what would currently be considered practical. Nevertheless the technology developed for CLIC is now being looked at for providing very high-energy electron beams for cancer therapy [2]. Making something like the FCC isn't just a matter of making a bigger copy of the LHC, it has its own specific challenges [3,4].

1 - https://en.wikipedia.org/wiki/Compact_Linear_Collider

2 - Slide 7, https://indico.cern.ch/event/578818/contributions/2487012/at...

3 - http://fcc-ee.web.cern.ch/content/accelerator-challenges

4 - https://indico.fnal.gov/event/16753/contributions/39405/atta...

Accelerator physics would have been unlikely to have progressed as far as it has without HEP. Beam line components for cyclo-/synchrotrons up to proton therapeutic energies are not seen in non HEP facilities (material physics).

FCC of course will not produce spinoffs that have already spun off, but what exactly will spin off we obviously can't predict very precisely.

I think you're engaging in a bit of cargo cult thinking here. FCC is analogous to early HEP, but it's an error to think that analogy implies similar outcomes. The sheer scale of FCC argues against similar sorts of direct spinoff. And indirect spinoffs are a poor justification for anything -- they can come from anything, after all, so provide no justification for a specific approach.