[HN Gopher] New exotic matter particle, a tetraquark, discovered...
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New exotic matter particle, a tetraquark, discovered at CERN
Author : mherrmann
Score : 385 points
Date : 2021-07-30 15:04 UTC (7 hours ago)
(HTM) web link (phys.org)
(TXT) w3m dump (phys.org)
| 4e530344963049 wrote:
| https://trimread.org/articles/31
| spxtr wrote:
| > The new particle contains two charm quarks and an up and a down
| antiquark. Several tetraquarks have been discovered in recent
| years (including one with two charm quarks and two charm
| antiquarks), but this is the first one that contains two charm
| quarks, without charm antiquarks to balance them.
|
| This is not the first time a tetraquark has been measured, but
| instead it's the first time a tetraquark with two charm quarks
| and no charm antiquarks. That's still nice work, but I was
| initially confused by the headline ("didn't they discover those
| already?").
| archsurface wrote:
| Why do these things take so long to find? Do they not show up in
| all collisions - why not, wrong matter, wrong speed? Do they
| regularly appear, but the "camera" has limitations? Is the
| "camera" all-seeing, but measurement interpretation inefficient?
| All/some of the above?
| ManBlanket wrote:
| I think it's a matter of theory supporting observed data. They
| point the, "camera" at a bunch of experiments, which generates
| a ton of data, then it's up to theoretical physicists to
| explain the results. Once the results of a theory have been
| explained and then reproduced it stands on solid ground. I'm
| just speculating, of course. But that is sort of how astronomy
| works, at the polar opposite end of a similar field.
| mirthless wrote:
| Does it fit into the standard model? I thought higgs boson was
| the last undiscovered particle according to the standard model.
| xhrpost wrote:
| You're referring to elementary particles. This is not
| elementary as it is composed of Quarks, which are part of the
| standard model and are elementary.
| x3n0ph3n3 wrote:
| tetra-quark: 4 quarks. It's composed of particles that are
| already part of the standard model, just an a previously unseen
| arrangement.
| ur-whale wrote:
| Particles are compositional.
| [deleted]
| jdeaton wrote:
| I wonder if the sophons from Trisolaris would have blocked this
| discovery.
| tux3 wrote:
| The article points to an ongoing conference as the source,
| unfortunately (despite having no registration fee) the live-
| stream is password protected for non-participants :(
|
| https://www.eps-hep2021.eu/live_stream/
|
| Edit: It seems the talks may be released, in the end
|
| >We would like to record your presentation at the EPS-HEP2021
| conference and make it publicly available via the INDICO page and
| the DESY media streaming server until one week after the end of
| the conference.
| jandrese wrote:
| They probably don't want internet randos jumping in and
| flooding the chat with porn.
| tux3 wrote:
| That makes sense for the zoom sessions.
|
| But, although I've never run a conference, I naively can't
| see that broadcasting the plenary session's video a little
| broader (to the three to five latecomers likely to stick
| around!) would really cause problems.
|
| Not to be a stereotypical "Concerned Facebook Taxpayer", but
| in general I'm really fond of CERN's transparency, and I
| appreciate all the work they do to keep science open. They're
| usually way ahead of the field and it's refreshing to see, I
| love following what comes out of the LHC data.
|
| So all that to say, maybe I've set my expectations a little
| high when it comes to physics and public access =)
| kkylin wrote:
| Many online conferences I've attended this past year have
| both a Zoom meeting for registered participants and a
| YouTube "simulcast" for people who don't care about asking
| questions. I haven't run one and don't know if the
| logistics are complicated; maybe the organizers just didn't
| think of doing it. Anyway, these days most conferences seem
| to be pretty quick at putting videos out, though of course
| our attention will be elsewhere next week...
| xondono wrote:
| Congratulations for the discovery of the next epicycle!
| amai wrote:
| What is the charge of a tetraquark? Is it neutral?
| jjk166 wrote:
| This particular one is +1e but there are many other forms a
| tetraquark may be able to take.
| whatshisface wrote:
| A tetraquark is four quarks. There exist three -1/3e quarks
| (dsb), three +2/3e quarks (uct), and then their +1/3e and -2/3e
| antimatter counterparts. 1e is the charge of one electron. The
| stability of a tetraquark is mainly a color/strong force thing
| and the electric charge comes along for the ride. Stable atomic
| nuclei, which are held together by the strong force, go up to
| +83e and they still don't fall apart due to electric repulsion.
|
| However, there is one constraint that might show up in charge.
| Tetraquarks always have two antiquarks, which is necessary for
| the color charge to come out to zero. Working out every
| possible combination is left as an exercise for the reader. :)
| im3w1l wrote:
| The highest possible charge is 2/3 + 2/3 + 1/3 + 1/3 = 2.
| Every swap of a quark to a lower charge one reduces the total
| charge by 1. So the possibilities are 2, 1, 0, -1, -2.
| pseudobry wrote:
| I recently finished The Three-Body Problem and The Dark Forest,
| which explore the concept of aliens using their super advanced
| technology to mess with the results of Earth's particle
| accelerators, thereby stopping humanity's ability to develop
| technology based on new physics.
|
| Is this discovery exciting? Or are we living in The Three-Body
| Problem?
| tomudding wrote:
| Unrelated to this topic, but Death's End is also a great book
| if you haven't started reading it. I can also recommend Ball
| Lightning which more or less takes place before the events in
| the The Three-Body Problem.
| majkinetor wrote:
| You spoiled it for me, I am on 1/4 of the first book :S
| whytaka wrote:
| Oh blood, I just got this book. Is this a huge spoiler?
| pseudosudoer wrote:
| Don't worry, I'll just use a sophon to revert your memory.
| rsynnott wrote:
| Eh, it's hinted at, pretty early on. If you knew there were
| aliens in the book, I don't think it's THAT huge a spoiler.
| BrissyCoder wrote:
| No not at all. Keep reading.
| ASalazarMX wrote:
| It's plot-establishing, but not a huge spoiler.
| svennek wrote:
| Well, it kinda spoils some/most of book 1.
|
| But IMHO the book 2 is the best and most intriguing anyways
| and that is totally unaffected...
| kryptn wrote:
| Same. It's been on my list, but this is more detail than I
| wanted to see.
| efsavage wrote:
| Rest easy, there is a _lot_ more to the books than that.
| bequanna wrote:
| Interesting.
|
| For what reason are the aliens trying trying to stop us from
| discovering new physics? Stop us from blowing ourselves up?
| Blowing them up?
| godelski wrote:
| The aliens are coming to Earth to take it over. They aren't
| much more advanced than us and so don't want us to be more
| advanced than the fleet that arrives (it takes them a few
| hundred years to get to Earth).
| sylens wrote:
| Without ruining too much of the books (they are worth a
| read), there is conflict between us and the aliens and
| limiting technological progress is an important part of their
| strategy
| misiti3780 wrote:
| which book was better?
| ASalazarMX wrote:
| In the books, the Sophons got in the way of the accelerated
| particle beam but somehow avoided being destroyed themselves.
| They wouldn't have allowed a new particle to be discovered.
| godelski wrote:
| They were destroyed but could bring themselves back together.
| The thing is that the particles are intelligent so could
| break apart in random ways that didn't match what particle
| physicists expected (they would then recombine outside the
| detector as to not be exposed).
| FinanceAnon wrote:
| If aliens don't like us, then why wouldn't they just destroy
| us, rather than troll our physicists and mess with the results?
|
| Why would they specifically mess with the particle accelarators
| at this point? Why not with earlier physics?
| AdamN wrote:
| In the book that's the state of human science when they learn
| of our existence. Also, they want our planet and it will take
| them a long time to get to earth - so long in fact that they
| predict that if our physics is allowed to mature they won't
| be able to beat us militarily by that time. They need to stop
| progress asap.
| gizmo686 wrote:
| Spoilers below:
|
| _The Three Body Problem_ trilogy breaks down if you think
| about it too hard. The in-universe explanation was that the
| aliens did want to destroy us, and had an attack fleet
| heading towards us. However, the attack fleet was relativly
| slow, and they were concerned that by the time it reached us
| we would have advanced to the point where we might win in a
| fight. To prevent this, they sent smaller probes to us at
| near light speed. In theory, these weren 't capable of
| causing significant damage, but they could cause enough of an
| effect that they could make the results of particle
| accelerators useless. Without being able to use particle
| accelerators, we wouldn't be able to advance our knowledge of
| fundamental physics, so the aliens were confident that when
| their attack fleet reached us we would be defenseless.
|
| By itself, what I have written is not particularly absurd,
| but if you look at the other things those advanced probes
| ended up being able to do, they could have easily just killed
| everyone.
| ASalazarMX wrote:
| Killing everyone is too much to ask, remember they were
| ultimately just protons, physically they're not more
| powerful than cosmic rays.
|
| Their strength was information gathering and special
| effects.
| HotHotLava wrote:
| Tbf, from the way they were described it should have been
| fairly easy to defeat the Sophons even without any
| science-fiction technology; just build e.g. 10-20
| particle accelerators distributed over the world and take
| measurements close enough in time to each other that you
| cannot be at multiple sites without exceeding the speed
| of light. Then at most 3 of them could be corrupted for
| any given run, and these can be thrown out as statistical
| noise.
| xster wrote:
| I think the argument was that they could send Sophons
| faster than we can build particle accelerators.
| gizmo686 wrote:
| Protons that could cause controlled visual hallucinations
| in people. If they can cause that level of interference
| with our nervous system, they can kill us. Even if they
| were somehow limited to visual hallucinations, a well
| timed hallucination is easily lethal. They probably ought
| to be able to hack into computer systems with that as
| well.
| wdwvt1 wrote:
| Totally agree with this, the effort to retard development
| could have been better spent with a myriad of ecosystem
| destroying actions or geopolitical manipulations. Also just
| send the indestructible probe to kill every human...
|
| My bigger problem with this book was that the author seems
| to wholely confuse secrecy for strategy. The entire conceit
| behind the wallfacers seemed ridiculous to me. The best
| strategic plan need not be secret (eg MAD). Make it clear
| that humanity will destroy every planet in the solar system
| and you've got at least MAD in the centuries the
| trisolarians will take to arrive.
| saiya-jin wrote:
| They cared about our stable single sun more than planets.
| We were not on the level to destroy our sun, or the
| planets themselves
| gizmo686 wrote:
| More spoilers below:
|
| They actualy did a fair amount of geopolitical
| manipulations. That formed most of the plot.
|
| In the end, it turned out to be MAD that saved us, but
| setting up the MAD scenario involved secrecy from them
| (or else they would have stopped us before we could
| trigger it), and from the rest of humanity (because an
| official plan to destroy Earth would never have been
| approved).
| shhsshs wrote:
| > In the end, it turned out to be MAD that saved us
|
| Read the rest of the series and this answer gets more
| interesting. I will not say any more about the outcome
| (spoilers)
| wdwvt1 wrote:
| It seems like the manipulations were exceedingly silly.
| It seems like having the sophont start a nuclear war
| would be straightforward. It was hard for me to suspend
| disbelief in the sense that it had planet-sized
| computational power and the ability to manipulate some
| information on the subatomic level, but couldn't find a
| vulnerability in aging nuclear launch protocols? The
| history of near misses with human controlled nuclear
| weapons suggests a variety of vulnerabilities exist that
| wouldn't require e.g. directly hacking into command and
| control. Could it spoof images/data to a sub? Could it
| cause hallucinations in a large sensor array that feeds
| data to Norad or a Chinese/Russian equivalent?
|
| Re MAD: I think a plan to destroy Earth would have been
| easily approved - much like it was in 1960-now, with ICBM
| and SSBN retaliatory strike capability. Obviously
| somewhat different in that those MAD-based nuclear wars
| would be extinctive but not deny the planet to the
| trisolarians, but the idea that human governments aren't
| ready to commit to that seems wrong given our history.
| bmh100 wrote:
| The aliens specifically wanted Earth because of its life.
| A nuclear war would damage the planet's ecosystem too
| much.
| rsynnott wrote:
| The sophons don't seem to be able to do anything much
| beyond bother particle accelerators. The later droplet
| probes _are_ very nasty, but it's at least implied that
| those weren't even available at the time they set out.
| JetSetWilly wrote:
| Because your interstellar equivalent of the CIA can obtain
| the political capital to prevent a civilisational rival from
| emerging via subtle manipulations, but it can't obtain the
| political capital and consensus needed to commit wholesale
| genocide.
|
| There's a big difference between the scenarios.
| midrus wrote:
| Maybe because we're their big brother tv show or just their
| zoo
| nolok wrote:
| Haven't read those specific books, but "keep the species at
| the level they were when discovered for preservation" is a
| very common trope of such things, and usually mapped on how
| humanity considers that "preserving a species" means keeping
| it exactly as they were when first discovered.
| yarky wrote:
| If you insist on looking at it from our perspective, how
| about curiosity? Let's see how far they (us) keep trying to
| make sense out of this nonsense. Trolling in the name of
| science I guess.
|
| People from North Sentinel Island might ask themselves the
| same question about us.
| artursapek wrote:
| I troll people I don't like all the time
| kingkawn wrote:
| Because they're hundreds of years of space travel away so
| they send sentient protons to sabotage our particle physics
| so that we can't develop advanced enough technology to stop
| them by the time they arrive.
| sweetheart wrote:
| While the entire series is absolutely incredible, I _loved_
| the premise of human beings knowing 400 years in advance
| that aliens are coming. Such a fascinating start to the
| trilogy.
| joshspankit wrote:
| Here's a possibility: They are in the next universe over, and
| so far the only thing that passes between is gravity. Fine-
| grained control over gravity could allow them to mess with
| things but not destroy us (if they even wished to. I don't
| even think Earth would vote to destroy an unknown
| civilization if the roles were reversed)
| maininformer wrote:
| maybe we are their toys, or maybe our emotions is their
| energy source
| rsynnott wrote:
| In the Three Body Problem, the naughty aliens break
| reproducibility in particle accelerator experiments; they start
| giving random results. So we're good for now.
| f6v wrote:
| It's a great book, but it suffers from the same old issue. A
| civilization that is capable of packing a robot into particle
| by manipulating higher dimensions doesn't need to take our
| planet. They could terraform Mars or any other planet they
| want.
| s5300 wrote:
| Perhaps we look to be an exceptional vacation spot, and there
| are space Karen's who desire an "all natural" planet instead
| of a terraformed one.
| hllooo wrote:
| iirc the solar system contained the closest planets, which is
| why they chose it. I don't think it matters if they want mars
| or earth, there's no way we would let them do that (send a
| massive military fleet definitely just to mars). they wanted
| to ensure their technology remained superior by the time they
| arrived
| alasdair_ wrote:
| I had the same problem with the books. If the sophon is that
| omniscient and that powerful, it could do far more than just
| mess with experiments.
|
| I also never understood the wallfacers - why can't they
| communicate via encryption, using a private key stored in
| each individuals mind alone?
| bo0tzz wrote:
| How would you use that private key without it 'leaving'
| your mind?
| danielheath wrote:
| The same way you use a private key in a computer without
| transmitting it?
| EthanHeilman wrote:
| The sophons are not that powerful and have very limited
| capabilities. Humans perceived as being very powerful
| because we doesn't understand how they work and they are
| being used to frighten us. It's like showing a gun to
| someone who doesn't know what a gun is. The limitations
| such line of sight, range, limited ammo are not immediately
| obvious. It looks as though you have a god-like ability to
| strike anyone dead by wishing it.
| micromacrofoot wrote:
| Couldn't trisolarans have broken the encryption? Many of
| our old methods of encryption have been rendered obsolete
| by our own technology.
| shoto_io wrote:
| Why not just for fun? Like riding horses even though you have
| a car.
| coldacid wrote:
| Or trolling.
| dice wrote:
| "Teasers are usually rich kids with nothing to do. They
| cruise around looking for planets that haven't made
| interstellar contact yet and buzz them."
| "Buzz them?" Arthur began to feel that Ford was enjoying
| making life difficult for him. "Yeah," said
| Ford, "they buzz them. They find some isolated spot with
| very few people around, then land right by some poor
| unsuspecting soul whom no one's ever going to believe and
| then strut up and down in front of him wearing silly
| antennas on their head and making beep beep noises."
|
| -- HHGTTG
| cmurf wrote:
| Human story tellers are very attached to humanity, so the
| stories tend to anthropomorphize aliens. Most alien stories
| rehash old religious and hero stories. What do we have to
| offer aliens? In the category of vague as well as less is
| more, _Arrival /Stories of Your Life and Others_ are about as
| compelling as it gets - humanity hasn't yet achieved full
| potential, going further out on a limb is folly (however
| entertaining it might be, it becomes less compelling).
|
| The more truly alien, the less in common we have in all
| respects, the more boring that story turns out to be because?
| We're a selfish, self-interested, loathsome species who
| consistently overestimates its importance. The more different
| a fellow human is, the vast majority of people reject that
| individual because of their (weird) non-social behaviors.
|
| So these alien stories strike me as deification, angels,
| devils, i.e. the supernatural, and don't adequately explain
| why or how any alien civilization would take interest in us,
| except via our own attachments to ourselves. This is central
| to good science fiction because they are stories ultimately
| about exploring something about humanity, it's not really
| about aliens at all. They're entirely incidental even if they
| seem important, aliens are just a literary device. But
| getting to science-non-fiction, a factual case of aliens,
| that's quite hard for most humans to imagine at all.
|
| Consider how poorly most people coped with covid, and then
| consider how much more traumatic an alien visit would be,
| even assuming they were nice.
|
| In Arthur C. Clarke's _Childhood 's End_ (1953) those aliens
| were "nice" but with a really big caveat. (And neatly
| explained devils.) But again, humans are the central part of
| that story, not aliens. It wouldn't and couldn't have been
| interesting to focus on the interests of the aliens without
| us being part of the story - we're just too self-interested
| by nature. The aliens' interests would have been boring to
| us, we just don't have the necessary common frame of
| reference with such beings. How could we?
| micromacrofoot wrote:
| Spoiler: It took them so long to get to earth that they were
| concerned about humans becoming a formidable opponent in the
| meantime. Had human advancement not been halted humans would
| have much faster access to Mars than they would.
| WORMS_EAT_WORMS wrote:
| The whole book is fun and creative fiction. Just enjoy it
| like you would enjoy any non-real TV or movie.
|
| If you haven't read the series, saw the spoilers here, and
| are no longer thinking about it... don't get discouraged. Pay
| off in Book 3 via the space concepts are worth it still. Mind
| blowing fun stuff
| Panoramix wrote:
| Spoilers ahead
|
| It was such a letdown, the book starts great, and then the
| explanation turns out to be magical Alien proton computers?
| Yikes. It was so promising.
|
| I eventually read the whole trilogy, I have very mixed
| feelings about it. It had some pretty cool ideas but it's
| hard to get past all the giant plot holes and outlandish
| fantasy. I guess you have to be in the mood to constantly
| brush off the bad parts (and boy there are many) and plunge
| forward.
| jjoske wrote:
| There where some good ideas in it but it never really
| worked for me, I have often wondered if it was translation
| issues.
| megablast wrote:
| Thanks for the spoilers.
| cynicalkane wrote:
| Spoilers.
|
| There are a few parts of the book, according to the
| translator, that are done in the manner of a Chinese
| folktale, which he tried to translate to a different style
| in English. I'm no expert, but I got the impression the
| sophont chapter was in this category. It has this
| otherworldly silliness with the multiple attempts to create
| a sophont going wrong in different dimensions, calculated
| to fit the repetitive pattern of a fairy tale.
|
| I think the thrust, which might be hard to read in
| translation, is this: we can't imagine the technology a
| superior alien species would come up with, so it's related
| as a fairy tale beyond technological realism.
|
| Anyway, I doubt it was meant to be hard sci-fi.
| shmageggy wrote:
| > _Anyway, I doubt it was meant to be hard sci-fi._
|
| Which was extremely disappointing, given that it was
| billed as such by many, and until the aforementioned
| mumbo-jumbo was doing a seemingly nice job on that front.
| visualradio wrote:
| A more materialist approach would be to say that it is the
| artists and authors of such books which are influenced by
| cosmos and the three body problem is an error detection
| code for repairing memory errors in collective
| consciousness to prevent civilizations from repeating
| unpromising patterns of development which have already been
| simulated.
| whymad wrote:
| True for what it is, but this is handled in the books. They
| literally don't want our planet, they want our _star_.
|
| And the dark forest: without a history of correlated
| interaction we have no reason to believe they will allow us
| to live, so we can't allow them to live, so they can't allow
| us to live.
|
| Eliding a more major spoiler, they absolutely intended to
| annihilate us on arrival and they would have gotten away with
| it if it weren't for, ah, "those meddling kids". Everything
| else was cloak and dagger.
|
| They definitely would have terraformed every planet in the
| system once they were sure we were gone. Or more likely
| deconstructed them, at that point in their development.
| wisty wrote:
| It's a good book, but while some elements are good sf it's
| not all hard sf. They're looking for a new planet and
| didn't even send a probe 50 years ago?
| EthanHeilman wrote:
| Because the trisolarans didn't know who was out there
| until they received a message from Earth. They were
| worried that if they sent a probe to another star then a
| more advanced civilization perhaps hiding around that
| star would see the probe arrive, trace the source and
| annihilate them.
| ansible wrote:
| > _True for what it is, but this is handled in the books.
| They literally don't want our planet, they want our star._
|
| That's... an odd reason. There are plenty of stars out
| there, unless the aliens started out right next door (like
| in Alpha Centauri) there's not much reason to go after
| _our_ star.
|
| I haven't read the books...
| seanc wrote:
| Well, the thesis is that with exponential growth and a
| modest amount of time there _aren't_ plenty of stars out
| there.
| Dylan16807 wrote:
| If you're growing that fast, then a system or two is a
| rounding error. You won't have plenty no matter what you
| do, so how about _not_ wiping out other species for that
| extra smidge?
| godelski wrote:
| > unless the aliens started out right next door (like in
| Alpha Centauri)
|
| This is where the aliens are (a trinary system). It still
| takes them 400 years to get to Earth and so they are
| trying to stifle Earth's technological advancements
| because 1) we know they are coming 2) our technological
| growth is faster than them (this is partially explained
| due to different biological and environmental factors.
| The aliens can't lie to one another and have
| environmental factors that frequently wipe out or pause
| their technological advancements). The aliens in question
| are supposed to be only a few hundred years (max) ahead
| of us technologically (or smaller than the difference in
| time that it takes them to get here)
| bkanber wrote:
| > unless the aliens started out right next door (like in
| Alpha Centauri)
|
| :D
|
| Strongly recommended reading.
| mannerheim wrote:
| > unless the aliens started out right next door (like in
| Alpha Centauri)
|
| They did.
| ASalazarMX wrote:
| Super spoiler below:
|
| Their tri-solar system was too unstable to terraform, they
| needed a stable solar system to migrate to. Of course ours
| was the nearest with an habitable planet (otherwise there
| wouldn't be much of a story), so they can immediately
| colonize Earth, and probably begin the centuries-long process
| of terraforming the neighboring planets.
| rnjesus wrote:
| an aside: i really wish hn had a redaction-style, click-to-
| reveal spoiler system. not that i don't appreciate the
| spoiler warning here -- it's quite kind that people mark
| their comments as-such -- but even when i've seen "spoiler
| warnings" for other content that i'd rather not be spoiled
| on, it's very hard to not skim the next few proceeding
| lines out of habit (especially on mobile). i can't imagine
| i'm the only one who does this.
| cogman10 wrote:
| Still doesn't make sense. Why limit our tech when they
| ultimately want to just eliminate us all together?
|
| Drop a super virus on us or irradiate the whole planet. Any
| species capable of disrupting our particle accelerators is
| more than capable of wiping us from existence.
| AmericanChopper wrote:
| They did also send weapons towards earth ahead of their
| fleet. They arrived much faster than their fleet, but
| much slower than the sophons.
| dylan604 wrote:
| It's kind of like nuclear warfare here on Earth. If you
| want to eliminate every living thing, then sure do some
| sort of scorched Earth type of thing. However, that
| leaves the planet in an un-inhabitable condition.
|
| If you need to wipe out the inhabitants but leave
| everything else so you can now use it, you need to not
| destroy everything in the first place. Otherwise, you now
| have to terraform a planet that you chose because you
| didn't need to terraform it.
| EthanHeilman wrote:
| The book makes the claim that the sophons they send over
| are very limited. It seems reasonable to surmise that
| they could not create a super virus. Yet they can disrupt
| sub-atomic experiments. We are talking about an advanced
| basically magic tech the author made up for the purposes
| of the plot. So the author can set the rules that the
| magic tech can do X but not Y.
| temporalparts wrote:
| More spoilers:
|
| In the book, they were scared of humanity's technological
| growth rate. They were observing our technological
| advances and noticed that it was significantly faster
| than theirs. While they were, at the time,
| technologically superior, they were afraid that after the
| 250+ years it would take for them to get to Earth,
| humanity would have become technologically superior; too
| strong for them to overtake.
| numlocked wrote:
| That was probably the plan; but the "tech-blocking
| particle" gets here at the speed of light, ensuring that
| we are still sufficiently behind, technologically, by the
| time their e.g. virus or radiation gizmos arrive. It
| "freezes" development to ensure that they still have
| technological superiority when the much-slower, barely-
| relativistic, big guns arrive.
| SkyMarshal wrote:
| They could send the subatomic particles from Trisolaris
| to Earth at light speed, and then use the entangled pair
| of particles (one on earth, its mate on Trisolaris) to
| monitor events on earth in real-time.
|
| As already said, that preserves the planet, prevents a
| potential enemy from further developing technologically,
| and enables real-time monitoring of and interference with
| that enemy's activities.
| Vecr wrote:
| I can't reply to roywiggins for some reason, but it's
| possible that the solar systems are closer in other
| dimensions or something like that. Probably not though,
| because the higher dimensions are so small. I assume the
| author didn't think about it until it was too late, or
| they couldn't fix it.
| roywiggins wrote:
| >and then use the entangled pair of particles (one on
| earth, its mate on Trisolaris) to monitor events on earth
| in real-time.
|
| This, of course, breaks the known laws of physics, since
| lightspeed is a hard limit on the speed of causality. You
| can't use entanglement that way in the real world (if QM
| is anywhere close to correct)
| AmericanChopper wrote:
| The sophons themselves were a piece of magic science
| fiction. Which I think is fine because the author really
| doesn't ask you to suspend your disbelief all that much
| throughout the books. The star plucking is another
| example, as far as we know you can't use a star to do
| that.
|
| But accelerating them towards earth "at the speed of
| light" isn't exactly a problem. The LHC accelerates
| protons to about 3 m/s less than the speed of light, and
| as far as the plot is concerned the sophons travelling
| here at the speed of light, or some tiny fraction of a
| percent less than the speed of light doesn't make any
| difference.
| shoto_io wrote:
| Oh great! I just started reading the book...
|
| /s
| AlexCoventry wrote:
| There's also the weird aspect that [rot13'd for spoilers] gur
| fbcubagf frrz gb or noyr gb vasyhrapr naq dhrel znggre, ohg
| pna'g frrz gb ernq crbcyr'f zvaqf be xvyy gurz.
| bo0tzz wrote:
| Gung'f abg dhvgr evtug, gurl qba'g npghnyyl unir gur znff
| gb rkreg zhpu vasyhrapr ba nalguvat
| bkanber wrote:
| Gurl jrer cebgbaf, evtug? Fb gurl ernyyl pna bayl nssrpg
| guvatf nebhaq gung znff naq raretl enatr. Gurl pna zrff
| jvgu cnegvpyr nppryrengbe rkcrevzragf ohg pna'g nssrpg gur
| znpeb jbeyq.
| BrissyCoder wrote:
| TIL google translate doesn't do ROT13.
| amelius wrote:
| Or perhaps the laws of physics that we observe are becoming
| more complicated over time, as a consequence of some deeper law
| of physics.
| alasdair_ wrote:
| The simulation we all live in is getting a new patch with
| higher resolution models.
| blackboxlogic wrote:
| I wonder if we're in PROD, STAGE, QA or DEV? _waves
| humanly_
| whatshisface wrote:
| Two more technical treatments:
|
| https://cerncourier.com/a/new-tetraquark-a-whisker-away-from...
| https://lhcb-public.web.cern.ch/Welcome.html#Tcc
| thereddaikon wrote:
| Is this the one that makes all the Sci-Fi gadgets do the
| impossible? I need to know if I should be excited or not.
|
| /s
| dmitriid wrote:
| You just need to apply more quantum.
| [deleted]
| oldspleen wrote:
| someone please ELI5 and how this discovery is important for
| furthering our understanding of quantum numbers
| whatshisface wrote:
| The laws governing the strong force are somewhat well-known at
| this point, but calculations involving them are difficult and
| in many cases beyond our reach. Furthermore the fundamental
| constants are not known to a very high precision. Both of these
| problems can be addressed by collecting experimental data about
| how these particles behave in real life, both to pin down the
| constants, and to accept or reject calculation techniques.
| lcfcjs wrote:
| No 5 year old could follow that.
| xwdv wrote:
| Can someone explain the practical use for this? Better batteries
| or something?
| piyh wrote:
| Another tick forward in fundamental physics that will pay off
| as some theoretical framework getting slightly more grounded
| and paying off in a tangential way 70 years from now.
| skinwill wrote:
| Normal human here, can someone speculate on potential industrial
| uses?
| Zenst wrote:
| Too early for that, though does open up other science that may
| well. Might finally pave the way for gravity shields, food
| replictor...or nothing.
|
| The aspect that this tetraquark breaks down into something with
| more mass will certainly be interesting for study.
| nabla9 wrote:
| Nobody expects noting. No reason to expect anything whatsoever.
|
| The particle is incredibly short-lived, requires a massive
| particle accelerator to create, and is hard to detect.
|
| This is just another high-energy physics experiment. The hope
| is that someday something comes out that does not fit into
| existing models and is a sign of new physics.
| WaitWaitWha wrote:
| I am unclear if they produced a tetraquark particle, or they
| simulated the particle.
|
| > ... used Google's quantum computer to demonstrate a genuine ...
| Algol wrote:
| I don't see a mention of quantum computers in the article. I
| think LHCb detected the particle.
| akomtu wrote:
| The article (light on details, as usual) mentions that a slightly
| different configuration of a tetraquark would be very stable
| (again, not sure if that means nanoseconds or hours). If such
| stable multiquarks exist, without an electric charge they would
| be effectively untraceable, right? The only way to see such a
| particle would be to hit it precisely with an even smaller
| particle and get it to bounce back.
| sethhovestol wrote:
| The more likely (I'm not a physicist) is to watch the decay of
| the particle and trace it back from there.
| whatshisface wrote:
| > _The only way to see such a particle would be to hit it
| precisely with an even smaller particle and get it to bounce
| back._
|
| Bounce back from what force? Whatever forces would make it
| interact with a single particle would make it interact with a
| detector, which is itself made out of particles.
|
| They say the extra-stable tetraquark would only be susceptible
| to decay via the weak force, which means you'd have to wait
| around until it decayed, and then you'd often be able to see
| some charged remnants.
| akomtu wrote:
| Can such tetraquarks form semi stable macroscopic structures
| like atoms? For example, if they aren't completely neutral, a
| group of them would be able to maybe attract an electron and
| become a quasiatom of some sort.
| whatshisface wrote:
| The stable-to-strong-decay species they're talking about,
| bb anti-u anti-d, would have a charge of (-1 -1 -2 -1)/3 =
| -5/3 times the electron charge. I guess its antiparticle
| would be positive, so maybe an electron could hang around
| for a while. I don't know how long that tetraquark is
| expected to live, though.
| FreeFull wrote:
| The charge would actually be (-2 + 1 - 1 - 1)/3 = -1 of a
| proton's charge. There isn't any physically viable
| combination of quarks that would produce a non-integer
| charge. The article mentions the bb tetraquark can only
| decay through the weak force, but I'm not sure how long
| it'd live either.
| enkid wrote:
| I don't think that's a unique property to tetraquarks. Neutrons
| or neutrinos also are not electrically charged. I'm not sure
| what you mean by untraceable, but neutrinos rarely interact
| with other particles and many, many of them pass through you
| every second without you even noticing.
| danslo wrote:
| >Such proximity in mass makes the decay "difficult," resulting in
| a longer lifetime of the particle, and indeed Tcc+, is the
| longest-lived exotic hadron found to date.
|
| So... how long does it live?
| kmm wrote:
| Fun fact, the reason strange quarks are named strange is
| because when we discovered the first hadrons containing those
| quarks, they were strangely long-lived.
|
| Long-lived here meaning 10^-10 seconds, instead of 10^-20
| seconds. A whole tenth of a nanosecond!
| ansible wrote:
| That is actually quite a long time at the quantum scale.
| whatshisface wrote:
| The resonance width is inversely proportional to the lifetime,
| and if the resonance width is about 400keV, the particle would
| live for about 10^-21 seconds. For comparison, neutrons decay
| via the weak force in about 800 seconds, and delta baryons, a
| randomly chosen strong force decay, live for 10^-24 seconds.
| That makes this tetraquark long-lived for a strong decay, but
| that's way, way faster than a weak decay.
|
| https://en.wikipedia.org/wiki/Resonance_(particle_physics)
| Gravityloss wrote:
| So not usable as spaceship fuel
| whatshisface wrote:
| If you're allowed to use something produced in an
| accelerator as your fuel you can't beat antimatter, which
| is as stable as normal matter until Kirk orders warp one.
| adrianN wrote:
| I like black holes because once you have one you don't
| need an accelerator for refueling.
| https://arxiv.org/abs/0908.1803
| hnuser123456 wrote:
| Huh, "black holes move when you push them" is
| interesting. I suppose you could feed it with a beam, but
| focusing a beam down to attometer-size beamwidth seems
| like the hardest part, ignoring making a subatomic black
| hole in the first place. But sure, I suppose capturing
| the radiation and redirecting most of it back into the
| black hole to push it and maintain its size, and just
| enough spare to push the ship itself at the same speed is
| feasible. Feels like a "free energy" invention but I
| don't see where it fails, especially if you could capture
| the majority of the radiation and feed it back into the
| black hole directionally, minus whatever used to
| accelerate the rest of the ship.
|
| I see, after more thinking, redirecting the radiation
| into the black hole would push the ship backwards with
| equal energy, so half the energy needs to be reflected
| back into the black hole at the correct direction, and
| the other half needs to shoot out the back as exhaust,
| and you'd need additional mass to prevent the black hole
| from shrinking and getting hotter.
|
| They seem to conceptualize a ~100-year black hole which
| balances semi-feasible mass, power output, and lifespan,
| which is radius 2.7 attometers, 1.8 million tons, and 17
| petawatts (!) of power. Looks like the saturn V was about
| 50 GW of power, so having ~500,000x the power, with only
| less than 1000x the mass (2900 tons vs 1.8m), means this
| thing would propel at hundreds of G's of acceleration,
| unless the ship itself was another 500 million tons? It
| looks like the WTC towers were "only" about 500,000 tons,
| so if you wanted to drop the acceleration to something
| survivable by humans, you would either need a much
| larger, colder black hole, or a ship of proportions of
| 1,000 WTCs.
|
| The 10-attometer black hole, with "only" 1 petawatt of
| power and mass 6.7 million tons and lifetime 5,000 years,
| seems more reasonable, you'd want a ship with mass 58
| million tons to have Saturn V levels of acceleration,
| only 100 WTCs and the black hole is still only about 10%
| the mass of the ship. Still, this is only about 6x the
| width of a proton where we're trying to beam on the order
| of a petawatt. We would probably need a lot of lasers
| packed densely together near the back of the ship to
| focus together on this point to avoid the beam itself
| being near capable of creating black holes, all coming
| from the same direction where we need to exhaust equally
| (or more) as much power to get the ship to keep up with
| the black hole.
|
| Next step would be to figure out how big of a net we'd
| need to collect enough mass to maintain the black hole
| but I've spent enough time on this already.
|
| Alcubierre drives almost seem more reasonable than this,
| almost.
|
| Oh, and the temperature of this thing would be around a
| trillion degrees, pretty sure most of that radiation
| would be gamma rays. Need to figure out how to reflect
| gamma rays with efficiency. This is apparently around the
| temperature of a SMBH's accretion disk, the temperature
| of a new neutron star, and the temperature where matter
| doubles in mass due to relativistic effects.
|
| All this being said, if we can balance the mass of the
| black hole with that of the ship, with a black hole with
| lifetime 5000 years, and we achieve 1g constant
| acceleration, we can cross the galaxy in 24 years and
| park it for up to a few thousand years before needing to
| feed it to prevent it from getting too small/hot. https:/
| /en.wikipedia.org/wiki/Space_travel_using_constant_ac...
|
| Imagine if you could see the other side of the galaxy and
| make it back to Earth before you turn 50 (though Earth
| will have experienced 200,000 years), or, since once
| you're already at such relativistic speed, see Andromeda
| and come back before you're 60. Apparently we could round
| trip to the edge of the (Earth's?) visible universe in
| right around 100 years. Of course, by time you made it
| back, Earth would be 26 billion years older, the sun will
| have exploded, etc. Of course, if these are drone ships,
| we don't need to worry about human-survivable
| acceleration, and we could retrieve data much faster, but
| then no biological lifeform would have been there.
| zinglersen wrote:
| This was such a cool read, thank you!
|
| What is hardest for me to comprehend is probably the last
| part about time being relative. All this stuff makes me
| think about how everything is made of the same matter and
| then, what am "I"?
|
| Btw this part from the wiki link cracked me up "Constant
| acceleration is notable for several reasons: It is a fast
| form of travel."
| Gravityloss wrote:
| Power scales to the square of exhaust velocity while
| thrust linearly, so if you have a very good power to
| weight power source like a black hole, you can use a very
| high exhaust velocity and thus can get by with very
| little reaction mass. Which is good.
|
| Also, you can make a spaceship out of an asteroid (or
| from asteroid materials) so multi WTC mass is not a
| problem.
| Gravityloss wrote:
| There's always many considerations. Energy density,
| stability, what kind of energy can you convert it to, can
| it be directed easily, how hard is it to store etc...
| whatshisface wrote:
| Antimatter's reputation for being incredibly difficult to
| store comes from the fact that it's produced as
| individual particles. A superconducting antimatter hockey
| puck would be much easier to store than a cloud of
| antiprotons of the same mass.
|
| And yeah, you'll need a way to build gamma ray mirrors
| before antimatter reactions will push you in any
| direction (the energy comes flying out isotropically and
| we can't presently do anything to stop or direct it), but
| we can cross that parsec when we come to it. :-)
| 8note wrote:
| Superconductors pretty notoriously need to be kept cold,
| which adds another difficulty of cooling the antimatter
| without touching it
| kadoban wrote:
| For now. By the time anyone could even possibly create
| enough antimatter to matter (heh), critical temperatures
| should be much higher. The record is broken fairly
| commonly.
| whatshisface wrote:
| If it was surrounded by a cold mass that it could radiate
| photons to across a vacuum, its equilibrium temperature
| would be that of its container.
| human wrote:
| I would be so nervous to be in the middle of space with
| an hockey puck of antimatter.
| yccs27 wrote:
| I guess I'd be just as nervous in space with thousands of
| tonnes of explosive propellant. Spaceflight always
| operates on the very edge of what's possible, not of
| what's safe.
| jjk166 wrote:
| Presumably antimatter would be your energy source, but
| not your propellant. The gamma rays from a small number
| of annihilations would heat up a much larger amount of
| normal matter.
|
| At least for the first generation, you likely also
| wouldn't be using antimatter as the main source of
| energy, but rather as a method of initiating some other
| reaction. For example where in a conventional fission
| reaction you get a relatively clean split of a nucleus
| into two halves plus a few extra neutrons to drive a
| chain reaction, an antiproton will blast apart such a
| nucleus like a billiard break, allowing fission reactions
| with much less than a conventional critical mass. A quick
| burst of positrons hitting the surface of some lithium
| deuteride would be able to replace a fission primary and
| make a pure-fusion explosion. Either of these options
| could be used as either incredibly low-mass nukes for an
| orion drive or as a light weight reactor for a more
| conventional nuclear propulsion method. While about 600
| times less energy dense than pure antimatter, you're
| still talking 10 million times better energy density than
| our best current rocket fuels, while using several orders
| of magnitude less antimatter.
| ashtonkem wrote:
| Gamma ray mirrors sound like they'd be extremely useful
| for nuclear power too.
| coldacid wrote:
| I think that's what the dilithium crystals are for. ;D
| im3w1l wrote:
| Despite free neutrons decaying in 800s, there are many stable
| elements containing neutrons. Would it be possible to imagine
| a tetraquark as an ingredient of a stable particle?
| phkahler wrote:
| Are these decays equivalent to drops to a lower energy state
| where that energy is mass?
| whatshisface wrote:
| The term "lower energy state" is a funny one, because isn't
| energy conserved? What's happening is a drop to a more
| spread out state, where you have several particles making
| great time flying away from each other instead of one high-
| energy-density locus in the center.
|
| Edit: Just to clarify, the time-variant system exception
| does not apply in this case. It really is an entropy thing,
| moreso than an energy thing (which is constant in every
| particle decay that happens on Earth.)
| MengerSponge wrote:
| Fun fact: in the most general case, energy is not a
| conserved quantity.
|
| https://www.preposterousuniverse.com/blog/2010/02/22/ener
| gy-...
| tux3 wrote:
| This is lovely. Wikipedia sent me from energy not being
| conserved, to time translation symmetry breaking, to time
| crystals as a source of perpetual motion.
|
| Just need to find a tie-in to 5G and I can write my own
| time-cube parody website.
|
| (The article is also very interesting, of course!)
| debrice wrote:
| Isn't information a better unit?
| thechao wrote:
| MengerSponge's article is raising an extremely subtle
| point about how we translate modern physical theories
| into English: we do it _poorly_.
|
| Conservation laws (Noether's theorem) are dependent on
| the way the physics is voiced, mathematically. Saying
| "energy is conserved" is the moral equivalent of looking
| at Newton's laws and just _ignoring_ GR. GR tells us new,
| precise, and amazing things about conservation laws. It
| 's just that, unfortunately, they're a little hard to
| translate into English.
| whatshisface wrote:
| > _Saying "energy is conserved" is the moral equivalent
| of looking at Newton's laws and just ignoring GR._
|
| If you're not expecting the spacetime background to be
| changing rapidly during your experiment, it's pretty
| moral to say energy is conserved.
| teknopaul wrote:
| my friend that thinks if he plays the breaks properly on
| his EV he generates energy, will be happy very hear this.
| renewiltord wrote:
| All he has to do is push his Tesla to the top of the
| hill!
| whatshisface wrote:
| The idea that spacetime itself has energy, which balances
| out the apparent lack of energy conservation in matter
| fields, is a far stronger interpretation than the article
| suggests. Spacetime energy bends spacetime, which is why
| gravitational waves exist. It's even called the stress-
| energy tensor.
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