> but without a promise of practical applications, or at least a convincing argument that they'll find something interesting with this new collider, I find it really hard to justify the price tag.

I mean, you can say that about people going to the moon, right? What data are they going to get? Something about rocks and the consistency of the moon dust, right? The technologies developed in going to the moon got us so many things we didn't see from the goal.

This is the same for a lot of things around the frontiers of science! More experimental data is beneficial to all levels of science. Look at how many papers have been written in obscure and 'irrelevant' fields of higher mathematics only to -- 40 or 200 years later -- be found extremely relevant and useful?

The point is we don't know. It's not like we can't afford it. If the United States, for example, distributed the defense budget into social care and the sciences, we wouldn't be having a conversation about monetary distribution. It's not inherently mutually exclusive, and it doesn't have to be at the moment, either.

> Would knowing what physics does at 100TeV be any more valuable to us than a great work of literature? I'm not sure.

Those things aren't mutually exclusive.

> If the United States, for example, distributed the defense budget into social care and the sciences, we wouldn't be having a conversation about monetary distribution.

You tease us with such sweet words, something like Star Trek but more real.

> they're solving problems that matter less and less, and are increasingly less likely to be useful in any way

Can you expand on why you think this? I'm not a physicist, but I feel like one shouldn't discount the possibility of useful discoveries. I'd love to hear if there are reasons that's not true.

The problem is that the effects they're looking at are confined to such high energy and small length scales that they're utterly invisible to things even on the scale of a single proton. It's very difficult to imagine how (or even why) one would ever build a device that takes advantage of a TeV scale effect to do something useful, given that these effects are meaningless to the sorts of matter we care about and interact with.

Is it possible that we might discover something revolutionary at 100TeV that will have gigantic consequences to our daily lives? Sure. But that's like saying that it's possible that there's a treasure chest full of gold buried in your backyard. Yes, if you dug up your back yard it is possible you'll find something amazing and life changing. But for right now, we don't really have any convincing reason to think that's the case, and you'd probably just be spending a lot of effort to dig a big hole in the ground.

Arguing that it'd have good effects like increasing your fitness and "who knows, you might strike gold!" isn't really a convincing argument for me to dig up my yard.

I agree with your point but it skips over a different equally important thing completely: technology built to create and observe events at these energies are not without value, similarly to NASA going to the Moon and inventing Velcro while at it (yes, not true, but you get the idea).

Actually I don't think I skipped over that. I explicitly mentioned "spinoff technologies" and in my analogy to digging a hole in your back yard I said

> Arguing that it'd have good effects like increasing your fitness and "who knows, you might strike gold!" isn't really a convincing argument for me to dig up my yard.

What I mean by this is that I don't think that the spin off technologies or discoveries from high energy particle physics research (i.e. the fitness you might gain by digging up your yard) are a valid justification for doing it.

Spin off technologies and discoveries will be found in almost any research endeavour, including other particle physics experiments that aren't just "build another collider, but bigger", they're not a justification for the research, they're a bonus.

You could say the same during invention of quantum mechanics: "They are looking at the effects on the scale of single atom/electron, hardly ever useful in our everyday life." Or about going to the space. You can never know what new discoveries bring.

Non-sequitur.

Quantum mechanics didn't require $10B (or whatever the equivalent would be in 1930-ish currency) to create. The "inventors" of QM were trying to explain measurements that were already made, quite inexpensively, that did not fit the model of nature that we had at that time.

Basically, the experiments were done, measurements made. Now the theorists were trying to understand what they needed in order to be able to provide a model that fit these results. This required a number of specific mental leaps of faith. Some of these are controversial even today. But they fit the experiments, so the issue for us is one of a mental model.

But ... and this is critical, not all of physics is quantum mechanical. Orbital calculations don't (normally) require QM. Steam engines, heat engines, etc. don't normally require QM.

The objections some of us have with classifying "all of physics being HEP" is that it is not, and the reality is that most physics do not require accelerators. Most new physics won't require accelerators.

A great example from earlier this year is the first sighting of a Majorana fermion[1]. Though this article also makes the mistake of "In particle physics, fermions are a class of elementary particles". Its not in particle (HEP) physics. Its in physics.

[1] https://news.mit.edu/2020/first-majorana-fermion-metal-quant...

The federal government just wrote a $2T stimulus check of funny money they pulled out of thin air to (largely) cover for their incompetence in handling the pandemic. But $10B (that's a factor of 200x less!) for basic physics research is somehow too expensive? Our priorities are way off.

I agree that it is too expensive and therefore probably should not be done. But this is a totally different argument than "probably useless".

Also, look at the military budget and think what is potentially more useful...

Except we know, and the founders of quantum mechanics also realized, that the properties of the matter we care about and interact with is driven by the properties of electrons and atoms.

That analogy has broken down. It’s not to say that we couldn’t learn something at 100TeV that could be useful or even revolutionary like QM was, but we also don’t really have any reason to believe that right now other than cheery optimism.

I’m all for finding high energy physics, I just don’t think it can justify it’s current budget in the quest for newer bigger colliders at higher and higher energies.

Yeah, but discovery costs resources, and on the margin a new accelerator is a less cost-effective means of producing productive new discoveries, sounds like.

That makes sense, thanks for the reply. At those energies, I guess you'd be hard pressed to make a useful 'finding' that could be utilized outside of a huge collider.