In his text Unreasonably Big Physics, Tetragraviton classifies the Texan SSC collider as marginally reasonable but other proposed projects are said to be unreasonable.
They include a wonderful 2017 collider proposal in the Gulf of Mexico. The structure would host some new, potentially clever 4-tesla dipoles and would be located 100 meters under the sea level between Houston and Merida.
The collision energy would be intriguing \(2\times 250\TeV=500\TeV\), almost 40 times higher than the current LHC beam, and the luminosity would trump the LHC by orders of magnitude, too. The depth is high enough not to annoy fish and to protect the tunnel against the hurricanes and the radius-of-300-kilometers ring would be far enough from beaches not to interfere with shipping. Quite generally, I think that the potentially brilliant idea that sea colliders could be more practical than the underground colliders should be honestly considered.
The cost is supposed to be comparable to the planned Chinese or European colliders – which means it's supposed to be very cheap. The adjective "cheap" is mine and unavoidably involves some subjective judgement. But I simply think that if someone finds a collider of this energy and this price "expensive", then he dislikes particle physics and it's bad if Tetragraviton belongs to that set.
Tetragraviton also mentioned a 15-year-old Japanese proposal for a very strong neutrino beam that would cost hundreds of billions of dollars and that will prematurely detonate the nuclear bombs across the world. It's handy. ;-)
I don't know exactly why you would want to do that but I know why we want a \(500\TeV\) collider. Every child knows why we want a \(500\TeV\) collider (or a plastic pony for Missy).
Well, I completely disagree with Tetragraviton that the Gulf of Mexico collider is unreasonable or impossible. If the calculations are right, it's actually a proposal you can't refuse. For the funds that only exceed the cost of the LHC by a small factor, we could increase the energy by a factor of 40. Isn't it wonderful?
He's not terribly specific about the arguments for his criticism but in between the lines, it seems that he finds tens of billions of dollars to be too much. Those amounts may be higher than his wealth but he's not supposed to pay for the whole thing. The world's GDP approaches $100 trillion a year. It's around $250 billion a day – including weekends – or $10 billion per hour.
Every hour, the world produces the wealth equal to the cost of the LHC dollider so the Gulf of Mexico collider could be equivalent just to few hours of the mankind's productive activity. Of course, some people may claim that it's arrogant to assume that the whole mankind contributes to something as esoteric as particle physics.
First of all, it's not arrogant – on the contrary, it's arrogant for someone to suggest that a human being could ignore particle physics. Take into the account that the extraterrestrials are watching us: Wouldn't you be terribly ashamed of the human race if it acts as a bunch of stinky pigs who won't dedicate even a few hours of their work to such groundbreaking projects of the global importance? Second of all, even if you compare the tens of billions of dollars to the funding for science only, it's small. Science may be getting roughly 1% of the global GDP which is one trillion dollars per year (globally). So such a unique project could still be equivalent just to weeks of the global spending for science.
It's totally counterproductive for Tetragraviton to spread his small-aß sentiments indicating that science shouldn't deserve tens-of-billions-of-dollars scientific projects. The mankind is getting richer, the rich enough countries can surely feed everybody and the poor countries may join as well, and there will be an increasing pile of excess cash (and workers who want some well-defined job).
It's natural for creative people and especially dreamers to have increasingly demanding visions and unless we screw something a big time, it should be increasingly easy to make these dreams come true. On top of that, every investment should compare costs and benefits – their differences and ratios. If a collider project increases the center-of-mass energy much more significantly than costs, then it simply deserves the particle physicists', engineers', and sponsors' attention.
Pure science will probably not get above $100 billion projects soon. But if you had some big project that would be somewhat scientific but also apparently very useful for lots of people or nations, I do believe that even multi-trillion projects should be possible.
The whole Apollo Program (whose outcome were all the men on the Moon) cost $25 billion of 1973 dollars which is translated to $110 billion of 2018 dollars. NASA's spending as a percentage of the U.S. Fed government's expenses peaked in 1966, under Lyndon Johnson's watch, when it was 4.41% or $6 (old big) billion. That one-year spending for one "applied scientific" institution already trumps the cost of the LHC when you convert it to current dollars.
Lunar missions have become boring for the taxpayers but other things may get hot again. Maybe there are great reasons to drill a hole through the Earth, build a tunnel around the Earth's circumference, or bring the ocean to the middle of Sahara, among hundreds of similar things I could generate effectively. Tetragraviton represents a textbook example of what Czechs call a near-wall-šitter (přizdisráč), a frightened man without self-confidence and ambitions. The Academia is full of this attitude, especially if you look at some typical bureaucrats in the scientific environment (who got to their chair mostly for their invisibility). But that's not the right attitude for those who should make similar big decisions. That's not the attitude of the men who change the world. That's not the men whom I really admire.