The best way to settle this question is to build a 100-TeV collider

November 1, 2015 1:49 AM

Nima Arkani-Hamed is championing a campaign to build the world's largest particle collider - "Two years ago, he agreed to become the inaugural director of the new Center for Future High Energy Physics in Beijing. He has since visited China 18 times, campaigning for the construction of a machine of unprecedented scale: a circular particle collider up to 60 miles in circumference, or nearly four times as big around as Europe's Large Hadron Collider (LHC). Nicknamed the 'Great Collider', and estimated to cost roughly $10 billion over 30 years, it would succeed the LHC as the new center of the physics universe. According to Arkani-Hamed and those who agree with him, this 100-trillion-electron-volt (TeV) collider would slam subatomic particles together hard enough to either find the particles that the LHC could not muster or rule them out, rescuing or killing the naturalness principle and propelling physicists toward one of two radically different pictures: that of a knowable universe, or an unknowable multiverse."

In 1979, when the Shah of Iran was overthrown, the family again returned to their homeland from the U.S., to the promise of free expression and possibility. Nima sat in on political discussions between his parents and their Western-educated friends, and recalls reading The Communist Manifesto as a Farsi comic book. But within a year, Ayatollah Khomeini began shutting down universities. Jafar, then working at Sharif University in Tehran, co-wrote an open letter with 14 colleagues denouncing the closures. The signatories were blacklisted; those who could be found were imprisoned or hanged, Jafar said. He went underground, and eventually paid $50,000 — his life savings — for smugglers to convey him and his family out of the country on horseback. When one smuggler in the chain of handoffs didn't receive full payment, the man abandoned Nima, his parents and his baby sister in the mountains between Iran and Turkey.

A week into a journey that was supposed to take two days, 10-year-old Nima developed a 107-degree fever and was too weak to walk. Jafar left his wife and children huddled in a valley and ran for help. Three hours later, he came across a group of nomadic Kurds, and among them, a leader of the Kurdish opposition to Khomeini. A swashbuckling hero in Nima's memory, the man sent horses to rescue the family. The boy, close to dying, sat slumped on the back of his mother's horse as they were led out of Iran under the cover of nightfall. "He was in very bad shape," Alasti said. To energize him, she directed his attention to the bright ribbon of stars sweeping across the sky — the Milky Way galaxy — and promised that when they made it to safety, he could get a telescope. "That kept him very, very engaged," she said, "to the point that it managed to keep him alive." Once safely across the border, the family made their way to Toronto...

(previously: 1,2,3)

posted by kliuless (31 comments total)

I have the feeling that somehow physics just keeps going, never to be finished.
posted by save alive nothing that breatheth at 1:36 AM on November 1, 2015

Eventually, we start finding turtles.
posted by Etrigan at 4:08 AM on November 1, 2015 [12 favorites]

"...rescuing or killing the naturalness principle and propelling physicists toward one of two radically different pictures: that of a knowable universe, or an unknowable multiverse."

Why not both?
posted by lazycomputerkids at 4:08 AM on November 1, 2015 [3 favorites]

Mr. President, we must not allow a particle collider gap!
posted by J.K. Seazer at 5:28 AM on November 1, 2015 [2 favorites]

"The Dead Collider" by Bruce Sterling is nearly my very first internet memory.
posted by bukvich at 6:08 AM on November 1, 2015 [1 favorite]

To power the thing, plans call for the largest hydro-electric project ever created, by the damming and flooding of Mongolia.
posted by Thorzdad at 6:30 AM on November 1, 2015 [3 favorites]

I remember when ten billion dollars sounded like a lot of money.
posted by Segundus at 7:26 AM on November 1, 2015 [1 favorite]

And when spread out over 30 years its even less.
posted by euphorb at 7:39 AM on November 1, 2015

Better than building ghost cities, I guess.
posted by RobotVoodooPower at 7:50 AM on November 1, 2015

I'd be quite amazed if this only costs $10 billion to construct. The LHC cost ~$5 billion to build (and more than a billion more for the massive ATLAS and CMS instruments that analyze the data from collisions). Those LHC instruments cost 5-10x as much as their Fermilab equivalents; assuming cost scales as energy, that'd suggest the instruments alone for a 100 TeV collider would cost ~$5 billion or more.

The LHC accelerator cost more like 10x-20x as much as the Tevatron at Fermilab; again, assuming energy scaling would imply a cost of more like $50 billion than $10.

A few days ago I had dinner with a particle physicist who's been involved at a senior level with both ATLAS and CMS. He was pretty skeptical about a next collider. As he put it, there was a "no-lose theorem" for building the LHC: either it would find the Higgs, or it wouldn't and we'd discover our basic ideas about the standard model were wrong. There's nothing equivalent for the next generation of colliders, and their cost will be outrageous. As a result, he (and many other particle physicists) are moving towards experiments that may be done on cosmic scales, and are working on developing projects like LSST.

Then again, the International Space Station cost ~$150 billion and is far less useful scientifically than any of these.
posted by janewman at 8:02 AM on November 1, 2015 [2 favorites]

> I have the feeling that somehow physics just keeps going, never to be finished.

This seems unlikely.

Modern physics is only about 300 years old, if you start the clock around the invention of the calculus, and we're already at the point where we can explain "nearly everything" - that the remaining problems are either at the very large end of things or the very small end of things or are existential or conceptual in nature ("does quantum mechanics really do what it says?") and perhaps not even physics at all.

There's a long way to go yet with chemistry - which is "just" applied physics if you have a perfect model of physics - and engineering, which is applied chemistry and physics (and math, etc) but it seems a certainty that in 300 more years there will be no more new physics, given how fast we've come in the first 300.

It might even be the case that some people reading this will still be alive when we reach a more-or-less steady state in physics, where there are still novelties around the edges but no more groundbreaking, worldview-changing discoveries left to make.

(This all assumes that technological civilization continues to flourish, which is by no means a foregone conclusion. We might have to put the particle accelerators aside for a couple of generations so we can fight climate change and the rapid degradation of the biosphere.)
posted by lupus_yonderboy at 8:13 AM on November 1, 2015 [1 favorite]

I'd like to think that there are many more dimensions to physics that will open up in the future. The fundamental question of 'why are the laws as they are?' remains, and although the tautologous answer "because if they weren't we wouldn't be here to see them" works, it doesn't say anything about universes governed by different laws. Which for all we know have had or do have some existential currency.

Modelling such universes may throw up some interesting lines of enquiry, although I couldn't even begin to guess at whether they'd have utility or practical consequences. But then, I have enough problems understanding that most of my personal mass is made up from the vacuum fluctuations in the space between the quarks in my nucleons (my doctor thinks it's actually the bacon sandwiches), so...
posted by Devonian at 8:38 AM on November 1, 2015 [1 favorite]

Then again, the International Space Station cost ~$150 billion and is far less useful scientifically than any of these.

Ironically, it's specifically talk of new and more powerful particle colliders that makes me wish we were building them in orbital hotlabs, rather than in the sole location currently capable of supporting human life.

And by "orbital" I mean preferably orbiting somewhere else entirely.
posted by Ryvar at 9:40 AM on November 1, 2015

janewman: "the International Space Station cost ~$150 billion and is far less useful scientifically than any of these."

Is there any generally agreed scale of how scientifically useful a facility is? It would seem that the LHC is narrowly focused and deep while the space station is shallower but broad. And while most of the space station science could probably be done remotely the efficiency of the science shouldn't effect how useful the resultant science is.

Besides ISS is as much about international science engagement and cooperation propaganda as it is about science. Something it is wildly better at than any of the collider projects.
posted by Mitheral at 9:58 AM on November 1, 2015 [3 favorites]

I'm not a physicist, but I enjoy Arkani-Hamed as a lecturer. I wish he were throwing his energy into doing physics rather than this.
posted by OHenryPacey at 10:07 AM on November 1, 2015

> and we're already at the point where we can explain "nearly everything"

Another way to phrase this is that we have mostly complete scientific answers for pretty well any question a bright child might ask about the universe - what is the sun, what are clouds, where did we come from, where did the sun come from, why is dirt different from paint and paint different from honey - and we have such a complete practical physics model that making any conceivable physical object is now often more an issue of the conception than it is of the manufacturing.

There are still questions at the edges - basic, existential questions, but ones that you really need to be an educated person to even understand.

We laugh at Sherlock Holmes for not knowing whether the Earth revolves around the Sun or the other way around, but can you blame an educated person who can't really explain what dark energy or a hadron is?

Physics will become mature, like many other disciplines before it, and mankind will continue.
posted by lupus_yonderboy at 10:09 AM on November 1, 2015

I can't blame an educated person for not knowing what dark energy is, given that physicists don't know what it is.
posted by justsomebodythatyouusedtoknow at 10:53 AM on November 1, 2015

The SSC would have been just a tiny bit larger than this... In the 90s.
posted by miyabo at 11:21 AM on November 1, 2015

No, the SSC's goal energy was 20 TeV per proton, or 40 TeV in a collision. 100>40.
posted by nat at 11:38 AM on November 1, 2015 [1 favorite]

It might even be the case that some people reading this will still be alive when we reach a more-or-less steady state in physics, where there are still novelties around the edges but no more groundbreaking, worldview-changing discoveries left to make.

You're ignoring two very big possibilities: a grand unified theory, and a theory of everything. Each of those things is huge, huge, huge, and I predict will result in fundamental changes to the way we understand the nature of the universe.
posted by TheNewWazoo at 11:56 AM on November 1, 2015 [1 favorite]

"Another way to phrase this is that we have mostly complete scientific answers for pretty well any question a bright child might ask about the universe - what is the sun, what are clouds, where did we come from, where did the sun come from, why is dirt different from paint and paint different from honey - and we have such a complete practical physics model that making any conceivable physical object is now often more an issue of the conception than it is of the manufacturing.


We still don't know why static electricity (specifically triboelectricity) actually works; the most recent experiments have basically disproven the working theories we've had for a long time. A bright child might ask why rubbing a balloon can make it stick to a wall — we know that it does, but the previous theories about friction-induced charging (knocking electrons off, basically) don't hold up to experimentation.

We're still not totally sure about granular convection — a bright kid might ask about the brazil nuts on top of the can.

As far as I know, we still don't totally get why moving a charged particle creates a magnetic field, we just know that it does and have great observations of it that make it really predictable.

We don't know why time, which should be symmetrical, only moves forward.

We don't know why there's more matter than antimatter.

And it's worth remembering that before Einstein and quantum mechanics, we thought that we'd solved all the physics problems and would be done entirely pretty quickly.
posted by klangklangston at 12:14 PM on November 1, 2015 [7 favorites]

Ironically, it's specifically talk of new and more powerful particle colliders that makes me wish we were building them in orbital hotlabs, rather than in the sole location currently capable of supporting human life.

And by "orbital" I mean preferably orbiting somewhere else entirely.

Those accelerators already exist -- plenty of cosmic rays with energies well over 100 TeV hit the Earth, and they're not coming from anywhere near us (it's one reason all the claims that the LHC would make a black hole that would doom us all were so unlikely -- if that could happen, it would already have happened naturally from cosmic rays).

Unfortunately, the cosmic rays are not concentrated enough to study in detail (unlike collisions in accelerators).
posted by janewman at 12:47 PM on November 1, 2015 [1 favorite]

Is there any generally agreed scale of how scientifically useful a facility is? It would seem that the LHC is narrowly focused and deep while the space station is shallower but broad. And while most of the space station science could probably be done remotely the efficiency of the science shouldn't effect how useful the resultant science is.

Besides ISS is as much about international science engagement and cooperation propaganda as it is about science. Something it is wildly better at than any of the collider projects.

The scientific value of the ISS is close enough to zero as to be negligible (it was sold as fostering things like microgravity experiments that it's not all that ideal an environment for). I agree with you that its value has been in fostering science engagement and propaganda (as well as in keeping Soviet rocket scientists employed after the breakup of the USSR).

The LHC is broader than just the Higgs (there are possibilities that it could discover a particle form of dark matter, help us to understand the matter/antimatter asymmetry, etc. -- a wide variety of very fundamental things we could learn about), but the Higgs was the one area where where we were sure to learn something.
posted by janewman at 12:51 PM on November 1, 2015 [1 favorite]

> > It might even be the case that some people reading this will still be alive when we reach a more-or-less steady state in physics, where there are still novelties around the edges but no more groundbreaking, worldview-changing discoveries left to make.

> You're ignoring two very big possibilities: a grand unified theory, and a theory of everything. Each of those things is huge, huge, huge, and I predict will result in fundamental changes to the way we understand the nature of the universe.

You misunderstood what I said.

I'm not at all saying that physics is over today - but that at some point in the future, conceivably in the next 50 years, there won't be any significant new physics. That's not "ignoring" either of those things, simply saying that there will be a point after we have resolved these questions where it's quite possible there won't be any more big questions to resolve.

The idea that physics will go on and there will always be huge breakthroughs for the rest of time seems very hard to swallow, and that's what I'm arguing against - not claiming at all that "we understand everything today".
posted by lupus_yonderboy at 5:54 PM on November 1, 2015

Our idea of the age of the universe has changed within my lifetime. I'm betting that astronomical observations are going to continue to disrupt our models of how the universe works.
posted by rdr at 6:01 PM on November 1, 2015

I'm not a physicist, but I enjoy Arkani-Hamed as a lecturer. I wish he were throwing his energy into doing physics rather than this.

I don't think his physics output is something you need to worry about. Granted, I am not a physicist either and only barely know the man--we exchanged polite nods in the cafeteria a couple days ago--but anyone who has contact with him can tell that Nima's base state is running full tilt in multiple directions at once. My husband, who is a physicist and knows him much better, reports no change in Nima's hyperspeed day-to-day activities.
posted by Diagonalize at 7:27 PM on November 1, 2015 [1 favorite]

We're at a point where we're making incremental but steady improvements in 'conventional' accelerator technology, where that means superconducting magnets and huge rings a la LHC. In the meantime, laser/plasma wakefield acceleration promises incredible acceleration over relatively small distances, but the technology is a long way from providing the bunch quality (think focusing) and luminosity (quantity) that a physics experiment needs.

We could build a massive ring and not find anything of note. That really is a problem, and the way that nuclear/particle physics has progressed, we are used to looking for a yay/nay on a very specific line of inquiry. In the early days this was simple: beam going into fixed target, set up some coincidence logic, maybe add a veto for a process you want to ignore, and you're done. Then we had cloud chambers, with armies of grad students combing yards of film for 'interesting' results. And now we have detectors bigger than houses generating terabytes of data, and we don't have enough room to store it all so most of it goes on the cutting room floor. Of course most of the data is 'uninteresting', but we are only looking for what we have decided to look for, and that to me is kind of unsettling.

As for SSC trauma, the SSC was not a total loss. On the accelerator physics side, a lot of work was done on fundamental beam physics, such as collective beam instabilities, which needed to be understood for future accelerators anyway. This sort of work is not as sexy as finding the top quark or the Higgs, but no less essential to the cause.
posted by Standard Orange at 7:27 PM on November 1, 2015 [3 favorites]

I'm not a physicist, but I enjoy Arkani-Hamed as a lecturer. I wish he were throwing his energy into doing physics rather than this.

If you don't have some physicists doing this sort of administrative service work, the wheels fall off.
posted by sebastienbailard at 2:15 AM on November 2, 2015

> Eventually, we start finding turtles.

The good thing is, once we build a big enough particle accelerator to find the turtle particles, the work should be smooth sailing from there on. Turtles are surprisingly fast, but it's true they're not very fast compared to massless particles. Turtle collisions should be somewhat safe to observe even in cheaper facilities - just a simple enclosure is usually enough. Besides, low-energy turtle-to-turtle collisions are often very safe to the turtles too; they have shells of their own, you see. You only need to find a few to perform repeatable experiments. I'm not a physicist, but the transition equation goes something like "turtle + turtle + n lettuce = SCIENCE".
posted by wwwwolf at 10:01 AM on November 2, 2015 [3 favorites]

The idea that physics will go on and there will always be huge breakthroughs for the rest of time seems very hard to swallow, and that's what I'm arguing against - not claiming at all that "we understand everything today".
lupus_yonderboy

I imagine this exact sentiment was expressed in the late 19th/early 20th century physics community. I imagine it was expressed 300 hundred years ago after calculus arose and Newton's work and it probably seemed that everything would shortly be worked out.

Not that you're necessarily wrong, but the history of physics itself seems filled with reasons to not be so confident that an endpoint of (near) total knowledge has been reached in the present.

It's exactly the discoveries and ideas that can't be predicted or imagined under the current system that come along and smash it.
posted by Sangermaine at 10:15 AM on November 2, 2015 [2 favorites]

The good thing is, once we build a big enough particle accelerator to find the turtle particles, the work should be smooth sailing from there on. Turtles are surprisingly fast, but it's true they're not very fast compared to massless particles. Turtle collisions should be somewhat safe to observe even in cheaper facilities - just a simple enclosure is usually enough. Besides, low-energy turtle-to-turtle collisions are often very safe to the turtles too; they have shells of their own, you see. You only need to find a few to perform repeatable experiments. I'm not a physicist, but the transition equation goes something like "turtle + turtle + n lettuce = SCIENCE".

Something something "electron shell."
posted by atoxyl at 11:15 AM on November 2, 2015 [1 favorite]