» »

strani: 1 2 3

kobilica ::

Jao kak je folk paranodičen zaradi tega poskusa , sploh pa še te mediji k bi jih najraje nekam poslav.

Raje upite da bo poskus uspel ne pa da štrajkate.

techfreak :) ::

Nobeden ne paničari (vsaj na STju ne). Imam veliko drugih bolj zanimivih ali pomembnih stvar o katerim moram razmišljati. Nimam še časa, da bi paničaril glede tega.

Samo pač je pomembno, da nič ni 100%.

Azrael ::

Zjutraj sem na HTV našel novico: Hakiran "Veliki prasak"

http://www.hrt.hr/index.php?id=48&tx_tt...

In še citat:
Grčki hakeri Greek Security Team uspjeli su provaliti u računala CERN-a. Samo nekoliko sekundi dijelilo ih je od preuzimanja kontrole nad detektorom LHC-a. Srećom, ipak nisu uspjeli hakirati posljednje računalo.

Se še komu bere kot kak opis na ravni Movie OS filmov B produkcije?
Nekoč je bil Slo-tech.

OmegaBlue ::

Jap ;)
Never attribute to malice that which can be adequately explained by stupidity.

techfreak :) ::

@Azrael: :))

Saj vsi mediji pišejo bolj tako ...

jeryslo ::

Jao kak je folk paranodičen zaradi tega poskusa , sploh pa še te mediji k bi jih najraje nekam poslav.

Raje upite da bo poskus uspel ne pa da štrajkate.


Ti bi bil tudi živčen če bi vedel kdo sodeluje pri poskusu:D:

 Gordon Freeman

Gordon Freeman

ALT ::

mene pa zanima neki, za vse tiste ki trdijo da nas takšni delci neprestano bombardirajo iz vesolja:
1. baje ta bombardiranja niso uporabna ker jih ne morejo natancno zaznat, kako pa potem vejo kolksno moc dejansko imajo?
2. kolk sm js uspeu razumet iz vsega tega je cilj trcit 2 taksna delca enga ob drugega in videt kaj se zgodi, v naravi pa taksni delci enostavno priletijo k nam, ne trcijo pa v isti tak delec ki gre tocno v nasprotno smer, tko da mi ni jasno kaj je pojnt zagovarjanja varnosti vsega tega s to teorijo? kot da bi reku da je celno trcenje avtov cisto varno, ker vidimo vsak dan po cesti vozit aute v eno smer??

Matrin ::

Če že mora bit. Mam raje da me pobere od radovednosti, kot pa od favšerije pa lakomnosti.

jype ::

ALT> 1. baje ta bombardiranja niso uporabna ker jih ne morejo natancno zaznat, kako pa potem vejo kolksno moc dejansko imajo?

Ne.

Problem teh trkov v naravi je ta, da ne vemo kdaj in kje se bodo zgodili in tako ne moremo imeti v neposredni bližini naprav, ki bi analizirale produkte trka.

ALT> v naravi pa taksni delci enostavno priletijo k nam, ne trcijo pa v isti tak delec ki gre tocno v nasprotno smer

Hitrost delcev je seveda relativna. Trk se vedno zgodi s hitrostjo, ki je le malenkost manjša od svetlobe.

Zgodovina sprememb…

  • spremenilo: jype ()

Yerpo ::

Madona, sem upal da bo od vseh slovenskih medijev vsaj ST malo bolj zrelo podal tole novico... pa je še slabša kot na RTV-SLO MMC portalu, ki ga ustvarja horda polpismenih študentov družboslovja.
Mrbit ja

gorucan ::

Rofl @ Jereyslo

;((
http://www.juregorucan.co.cc/

ALT ::

jype, torej sam produkte trkov ne morjo izmerit, moč ki jo imajo te delci pa lahko od daleč izmerijo?

bistvo drugega vprašanja je pa biu da trčijo ob neki na zamlji al karkoli, ne pa v delec ki leti s tako hitrostjo in močjo ravno proti njemu da se prav čelno trčita (si predstavljam da tut če se s kakim drugim slučajno trči pod nekim kotom spremenita smer ob trku, kar pa v primeru čistega čelnega trčenja ni možno) kot oni to poskušajo nardit..

jype ::

ALT> jype, torej sam produkte trkov ne morjo izmerit, moč ki jo imajo te delci pa lahko od daleč izmerijo?

Ne. Vseh produktov ne morejo analizirati, nekatere (dolgožive) produkte pa lahko zaznajo na zemlji. Produktom takega trka se reče "particle shower" in niso redki.

ALT> bistvo drugega vprašanja je pa biu da trčijo ob neki na zamlji al karkoli

Kot rečeno - stvar je relativna. Če trčita delec, ki miruje in delec, ki potuje z energijo 30 TeV, je trk popolnoma enak kot če čelno trčita delca z energijama 15 TeV, ali pa energijama 10 TeV in 20 TeV. Relativna hitrost "drugega delca" s "perspektive prvega delca" je v vseh primerih nekaj manj kot svetlobna.

Thomas ::

Jure spet "poenostavlja". Najmanj ena razlika je. Ko bodo v pospeševalniku trćili SNOP delcev s SNOPOM delcev, bo to nekaj, česar v naravai zagotovo nimamo.
Man muss immer generalisieren - Carl Jacobi

Saladin ::

Ko bodo v pospeševalniku trćili SNOP delcev s SNOPOM delcev, bo to nekaj, česar v naravai zagotovo nimamo.

Zagotovo je redko - sigurno pa se je že zgodilo (da se je snop iz eksplozije ene zvezde ali podobnega zaletel v snop druge eksplozije).
Dobro je kar nosi največ svobodne koristi/najmanj bolečine čim več sentientom
na najhitrejši, najvarnejši in najbolj moralen način za najdaljše obdobje.
"Utilitarianizem po Saladinovo"

Matevžk ::

Zagotovo je redko - sigurno pa se je že zgodilo (da se je snop iz eksplozije ene zvezde ali podobnega zaletel v snop druge eksplozije).

A-haaaa! Zdaj smo pa le izvedeli, kako so v vesolju nastale črne luknje! :D:D
lp, Matevžk

Saladin ::

Zagotovo je redko - sigurno pa se je že zgodilo (da se je snop iz eksplozije ene zvezde ali podobnega zaletel v snop druge eksplozije).

A-haaaa! Zdaj smo pa le izvedeli, kako so v vesolju nastale črne luknje! :D:D


Energija ob sesedanju velike zvezde je neprimerljivo večja od energije trkov posameznih snopov.

In btw. - vse črne luknje, ki jih poznamo, nastanejo zaradi ogromne gravitacije na majhnem mestu in ne velike količine energije na majhnem mestu.
Dobro je kar nosi največ svobodne koristi/najmanj bolečine čim več sentientom
na najhitrejši, najvarnejši in najbolj moralen način za najdaljše obdobje.
"Utilitarianizem po Saladinovo"

Thomas ::

Nobeden ne more garantirati, da tale dva snopa ne moreta kolapsirati v črno luknjo. Nobeden ne nore garantirati niti da moreta.

Terra incognita.

Zamesemo se več ali manj lahko samo na teorije, ki so z LHC na preiskušnji. Upamo lahko, da niso preveč napačne.

Vehemenca je odveč.

Zagotovo je redko - sigurno pa se je že zgodilo (da se je snop iz eksplozije ene zvezde ali podobnega zaletel v snop druge eksplozije).


In se "ni nič posebnega zgodilo"? Samo ena majhen GRB, mogoče?

NE VEMO. Jasno? Igrajo se pa, kot bi vse vedeli. Čeprav v isti sapi priznavajo, da ne vedo, da bo še "exciting"!

Kako se takim reče?
Man muss immer generalisieren - Carl Jacobi

Zgodovina sprememb…

  • spremenil: Thomas ()

Brane2 ::

Radovedneži ?

Sploh pa, kaj se tolk sekiraš ?

Tudi če bo črna luknja, bo prehod s tega na oni svet v veliki meri "Protokol-like" >:D
On the journey of life, I chose the psycho path.

3p ::

Brez panike. Black hole button ni dostopen preko mreže. Zahteva fizični dostop:
http://gizmodo.com/5048298/large-hadron...

Thomas ::

Sploh pa, kaj se tolk sekiraš ?


Nisem suiciden, najbrž zato.

Nimam niti nobenih iluzij, kako bo LHC kaj pametnega odkril, pa bi hotel tvegati.

Čeprav se mi tveganje zdi precej neznatno, je stava enostavno preveč visoka, da bi bila racionalno opravičljiva.

Cinične pripombe - "eh, še čutil ne boš!" in podobno - zadržte zase.
Man muss immer generalisieren - Carl Jacobi

jype ::

Thomas> Nobeden ne more garantirati, da tale dva snopa ne moreta kolapsirati v črno luknjo.

Tudi nobeden ne more garantirati, da bomo brez uporabe LHC preživeli kot vrsta.

Brane2 ::

Cinične pripombe - "eh, še čutil ne boš!" in podobno - zadržte zase.


Tole je absurdno.

V primeru jakcpota bo itak vse skupno- še prdca ne boš mogel "zadržati zase".

Če pa ne bo nič, pa si itak brezveze paničaril.

Lose-lose.
On the journey of life, I chose the psycho path.

Saladin ::

Pa recimo da se zgodi kak majhen GRB (za velikega ni dovolj energije).

Zdemoliral bi LHC in nekaj sevanja bi prišlo na površje. Dvomim pa, da bi bilo globalno prebivalstvo resno ogroženo.
Dobro je kar nosi največ svobodne koristi/najmanj bolečine čim več sentientom
na najhitrejši, najvarnejši in najbolj moralen način za najdaljše obdobje.
"Utilitarianizem po Saladinovo"

Zgodovina sprememb…

  • spremenil: Saladin ()

MrStein ::

Thomas:
Jure spet "poenostavlja". Najmanj ena razlika je. Ko bodo v pospeševalniku trćili SNOP delcev s SNOPOM delcev, bo to nekaj, česar v naravai zagotovo nimamo.

resonance cascade ? 8-O

Brane2:
Tudi če bo črna luknja, bo prehod s tega na oni svet v veliki meri "Protokol-like"

Ja, kaj pa če na mestu trka nastane computornium ?
Ne moremo vedet :))
Teštiram če delaž - umlaut dela: ä ?

Thomas ::

Pa recimo da se zgodi kak majhen GRB (za velikega ni dovolj energije).


Kdo je rekel da "ni dovolj energije"? Tudi vžigalnih atomske bombe nima "dovolj energije" za znatno uničenje. Energija pride iz eksploziva ne iz detonatorja. Vžigalnik je samo sprožilec reakcije.

Tako bi lahko bilo tudi tukaj. Morda je potrebno relativno malo, da se sproži kakšne sorte (sub)nuklearna verižna reakcija.

NE VEMO.

Štekaš že kej?

resonance cascade ?


Kje pa. To je čisto nekaj drugega.

Ja, kaj pa če na mestu trka nastane computornium ?


Kaj če bi se ustrelil v želodec, da bi si izrezal rano na dvanajsterniku?
Man muss immer generalisieren - Carl Jacobi

Zgodovina sprememb…

  • spremenil: Thomas ()

MrStein ::

1.) A nisi smajlijev opazil ?
2.) resonance cascade obstaja tudi v realnosti ? (google vrne samo reference na igro, vsaj na prvi strani)
Teštiram če delaž - umlaut dela: ä ?

noraguta ::

jaja padli bomo v krono-sinklastični inffibulu.
odešijo nas lahko samo še cerkev popolnoma brezbrižnega boga ali pa protokolarci , kateri itk navijajo za usodo starih trafalmadorcev.

Once upon a time on Tralfamadore there were creatures who weren't anything like machines. They weren't dependable. They weren't efficient. They weren't predictable. They weren't durable. And these poor creatures were obsessed by the idea that everything that existed had to have a purpose, and that some purposes were higher than others.
These creatures spent most of their time trying to find out what their purpose was. And every time they found out what seemed to be a purpose of themselves, the purpose seemed so low that the creatures were filled with disgust and shame.
And, rather than serve such a low purpose, the creatures would make a machine to serve it. This left the creatures free to serve higher purposes. But whenever they found a higher purpose, the purpose still wasn't high enough.
So machines were made to serve higher purposes, too.
And the machines did everything so expertly that they were finally given the job of finding out what the highest purpose of the creatures could be.
The machines reported in all honesty that the creatures couldn't really be said to have any purpose at all.
The creatures thereupon began slaying each other, because they hated purposeless things above all else. And they discovered that they weren't even very good at slaying. So they turned that job over to the machines, too. And the machines finished up the job in less time than it takes to say, "Tralfamadore."


konec koncev je precej bolj gotovo ,da lahko pri iskanju bolj učinkovitih sončnih celic nori znanstveniki ponesreči ustvarijo led9.
Pust' ot pobyedy k pobyedye vyedyot!

Thomas ::

konec koncev je precej bolj gotovo ,da lahko pri iskanju bolj učinkovitih sončnih celic nori znanstveniki ponesreči ustvarijo led9.


Kar počenjajo "nori znanstveniki" pri kemiji ... je že pripeljalo do smrtnih žrtev med njimi. Prve sinteze nekaterih spojin, so se končale tragično. Zanje, morda še za kakšnega asistenta.

Težko (a v dogledni prihodnosti mogoče), je narest kemikalijo, ki bi požrla svet. Tukaj precej dobro vemo kaj počnemo.

Pri trkanju snopov protonov s snopi protonov ... pa zadeva LAHKO postane večjega obsega. Ne rečem da bo nujno, pravim samo da ne vemo, kako je pravzaprav s tem.

Če pa ne vemo, pa ni treba prižigat sveče v prostoru, za katerega ne vemo, če ni morda smodnišnica.
Man muss immer generalisieren - Carl Jacobi

jype ::

Thomas> Ne rečem da bo nujno, pravim samo da ne vemo, kako je pravzaprav s tem.

In ker očitno nimaš pojma, se ti zdi pametno, če tega ne storimo.

Ker ne vemo.

Ne vemo tudi kaj se bo zgodilo, če tega ne storimo, a bo zagotovo pogubno.

Thomas ::

Jure se gre spet nek "sofizem".

Jaz nimam pojma, kaj se zgodi, če trčita dva visokoenergetska snopa protonov.

Jure nima pojma, kaj se zgodi, če trčita dva visokoenergetska snopa protonov.

Nobeden nima pojma, kaj se zgodi, če trčita dva visokoenergetska snopa protonov.

Jaz pravim, da bi poskus LAHKO bil nevaren, zato ga ne delajmo, dokler ga ne bomo mogli delati nekje v Vesolju, daleč od Zemlje.

Se pa zavedam, da je to zelo nepopularno stališče. Če imam prav, se ne bo vedelo, če nimam prav, se pa bo vedelo.

Vseeno se mi to zdi nujno povedat. Ne igraj se z ognjem, če treba ni!
Man muss immer generalisieren - Carl Jacobi

Matthai ::

Hehehe, zdaj smo te pa dobili!

A: Ej, tale GSO hrana je kul!
B: Hmm, ne vemo če je varna.
A: Ja itak da je varna, saj so delali teste, izračunali, itd.
B: Ja, ampak učinki GSO v real life niso bili še izmerjeni, GSO je lahko nevaren, zato ga zaenkrat še ne delajmo. Pravim samo, da se ne igraj se z ognjem, če treba ni.
A: B je nazadnjak, komunist in idiot!!!
B: ???

Namesto GSO lahko vstaviš poljubna nova oblika nadzora, ali pa LHC. Se mi pa zdi, da si bil glede GSO ti oseba A.
Zloraba oblasti, avtokracija in tema nikoli ne pridejo hipoma, vedno je vmesno
obdobje mračenja, ko se dan preveša v noč; biti moramo pozorni opazovalci
okolja in varuhi luči, da ne postanemo nemočni ujetniki teme. --W. Douglas

Thomas ::

Če nekdo je strupene gobe, magari genetsko modificirane, to še ne pomeni konca sveta. Mogoče zanj.

Tukaj so pa stave neprimerno večje. Samo Hawkingovo sevanje ne deluje - ali pa deluje mnogo bolj počasi - pa smo tam. Vsi. Konec zgodbe.

Hawkingovega sevanje opazili še niso. Je pa ravno ta pojav garancija, da bodo vse nastale črne luknje izhlapele, preden jih bo gravitacija potegnila proti središču Zemlje. Če seveda HS deluje v praksi ravnio tako, kot v teoriji.

Težko rečem, oziroma ne morem reči, kaj vse gre lahko še narobe, ko bomo temeljito pošejkali osnovne gradnike snovi.

Strangeleti, naj se v LHC ne bi tvorili. Baje, ni možno in zato se naš svet ne bo spremenil v slepečo in vročo kroglo.

Kljub temu je v načrtu detektor, ki bo zaznaval naravne strangelete. Ki v CERNu bojda niso možni.

Mau hecno, ane?
Man muss immer generalisieren - Carl Jacobi

Zgodovina sprememb…

  • spremenil: Thomas ()

Matthai ::

Saj pravim. Veseli me, da si se približal anti-GSO miselnosti.

Čeprav - po razmisleku ti dam prav. Ne bi pa delal velike panike glede tega. Ali pa samomora kot ona indijska dečva prejšnji teden...
Zloraba oblasti, avtokracija in tema nikoli ne pridejo hipoma, vedno je vmesno
obdobje mračenja, ko se dan preveša v noč; biti moramo pozorni opazovalci
okolja in varuhi luči, da ne postanemo nemočni ujetniki teme. --W. Douglas

jype ::

Thomas> Tukaj so pa stave neprimerno večje.

Samo za ljudi, ki ne znajo računat.

Thomas ::

Jure ... nisi vreden besede.

Matthai,

Življenja brez tveganja NI. Tvegaš ko ješ (ne)modificirano hrano, ko (ne) greš čez cesto. Življenje je veriga tveganj, nič drugega.

Ni pa nobenega razloga, da bi šli v tveganja, ki lahko ubijejo vse in vsakogar. Uničijo vse živo, s planetom vred, v takorekoč sekundi. Ali pa še v krajšem času, saj ne vemo.

Titanik je bil "nepotopljiv", po zagotovilih konstruktorjev in novinarjev. CERN je pa "absolutno nenevaren", po zagotovilih konstruktorjev in novinarjev, ki povzemajo za njimi.

Po eni strani trdijo, kako bodo "poustvarili Veliki pok". Po drugi trdijo, kako "se še bolj močni trki dogajajo nonstop".

Jaz nisem preveč Zelen, to je jasno. Ampak ne vidim razloga, da stankamo milijardo litrov becina v Savo in zakurimo. Še manj razloga vidim, da se igramo s črnimi luknjami, strangeleti, inverzijami de Sitter prostora ... al pa BOHVE kva zaeno rečjo. V tem je point, da se lahko zanašamo samo na en kup (nasprotujočih si) teorij, ki jih bodo zdej v CERNu preverjali.

Hvala lepa.
Man muss immer generalisieren - Carl Jacobi

Matthai ::

Thomas... se pravi obstaja možnost, da ne znamo izračunat da se ne bo v CERNu kaj zalomilo? Čeprav si eni domišljajo, da znajo to zračunat?

Kako se to aplicira na Protokol - kaj če se izračun ne izide in se bo po uploadu vse skupaj sesulo?
Zloraba oblasti, avtokracija in tema nikoli ne pridejo hipoma, vedno je vmesno
obdobje mračenja, ko se dan preveša v noč; biti moramo pozorni opazovalci
okolja in varuhi luči, da ne postanemo nemočni ujetniki teme. --W. Douglas

jype ::

Thomas> Ni pa nobenega razloga, da bi šli v tveganja, ki lahko ubijejo vse in vsakogar.

Zato bomo še naprej dajali prednost znanosti pred vraževerjem.

In pognali tisti pospeševalnik.

Še sreča, da se tebi sanja ne, kaj pomeni "snop delcev".

Thomas ::

Protokol bo samo skupek pravil za minimizacijo verjetnosti sesutja. Osebnega ali globalnega.

Protokol bo sigurno moral prepovedovati (bolje, onemogočiti) CERN tipa avanture.

Stvari grejo naprej, Gray Goo je čedalje bolj verjeten. LHC je možen Gray Goo trigger.

Protokol, ki ne zmanjša nevarnosti, ima negativno vrednost. Takega NOČEMO. Jaz samo špekuliram, kakšen Protokol (šege in navade) bo najbolj verjetno prevladal. Da bomo sploh preživeli. Ker brez njega ne bomo.

Še sreča, da se tebi sanja ne, kaj pomeni "snop delcev".


??? ... na plan z razlago, modrina!
Man muss immer generalisieren - Carl Jacobi

Zgodovina sprememb…

  • spremenil: Thomas ()

jype ::

Thomas> ??? ... na plan z razlago, modrina!

Naj te kar citiram:

Thomas> nisi vreden besede.

Piše na internetu - lahko poiščeš.

Thomas ::

Snop delcev v tem primeru pomeni, od človeškega lasu tanjši snop milijard protonov, ki bodo z doslej še nedoseženo energijo trkali v drug tak snop.

Baje, se iz tega lahko rojevajo hipotetični "božji delci" (Higgsovi bozoni), ne morejo se pa tudi hipotetični "hudičevi delci" (strangeleti).

Prvi prinesejo Nobelovo nagrado, drugi prinesejo pogubo sveta. Če se hipoteza seveda potrdi.

Ni pa nikjer rečeno, da Higgsov bozon ne naredi kakšne hude štale. Niti da jo. Jasno. NE VEMO.

Je tako težko razumet?
Man muss immer generalisieren - Carl Jacobi

Zgodovina sprememb…

  • spremenil: Thomas ()

jype ::

Thomas> Prvi prinesejo Nobelovo nagrado, drugi prinesejo pogubo sveta. Če se hipoteza seveda potrdi.

Možnost za zaznavo Higgsovega bozona se s številom delcev veča. Možnost za nastanek strangeletov se s številom delcev manjša. Če bi se potrudil razumeti fiziko, bi ti to bilo že jasno. RHIC je imel večje možnosti ustvariti strangelete, pa jih je ustvaril natanko nič (0). LHC jih bo še manj od tega.

Thomas> Je tako težko razumet?

Jah, ni neobvladljivo težko, ampak ti se sploh ne potrudiš, potem pa ne gre.

Thomas> Ni pa nikjer rečeno, da Higgsov bozon ne naredi kakšne hude štale. Niti da jo. Jasno. NE VEMO.

Higgsov bozon ne naredi nobene štale. Če obstaja, se obnaša po zakonih fizike. Če ne obstaja, so zakoni napačni. V nobenem primeru ne more narediti štale, sicer bi jo že.

O snopih delcev, GRB, nevtronskih zvezdah (ki niso črne luknje) in obstoju vesolja pa kdaj drugič, ker zdajle ne utegnem.

Preberi LSAG report.

Thomas ::

Lepo bi bilo, če bi imej jure tokrat prav. A žal nabija kar v ene tri dni, kakor skoraj zmerom.

> RHIC je imel večje možnosti ustvariti strangelete, pa jih je ustvaril natanko nič (0). LHC jih bo še manj od tega.

Od kod le, je to pobral? V naboljšem primeru iz neke nepreverjene teorije, v najslabšem si je izmilil kar med pisanjem. Kaj mislite?

Analizirajmo mau tale crap:

Higgsov bozon ne naredi nobene štale. Če obstaja, se obnaša po zakonih fizike.


Vsak delec se obnaša po zakonih fizike. Tudi nevtroni, ki povzročajo verižno reakcijo med uranovimi ali plutonijevimi atomi in kar vidimo kot atomski KABOOOM. Tudi oni se obnašajo po zakonih fizike, normalno.

> Če ne obstaja, so zakoni napačni.

Če so napačni, kako se potem lahko zanesemo, da je CERN pa 100% varen? Kako?

> V nobenem primeru ne more narediti štale, sicer bi jo že.

Pravi juretova teorija. A nevtroni (in strangeleti, če so), lahko naredijo veliko škode. V določenih pogojih, za katere samo ozka skupina trdi, da jih dobro pozna, a ne toliko, da bi mogla živeti brez LHC.
Man muss immer generalisieren - Carl Jacobi

Zgodovina sprememb…

  • spremenil: Thomas ()

jype ::

Thomas> Od kod le, je to pobral? V naboljšem primeru iz neke nepreverjene teorije, v najslabšem si je izmilil kar med pisanjem. Kaj mislite?

Poljudno gradivo, samo zate, še enkrat:

http://cern.ch/lsag/LSAG-Report.pdf:

5 - Strangelets
The research programme of the CERN Large Hadron Collider also includes
the collisions of ultra-relativistic lead and other nuclei (ions). The main
scientific goal of this heavy-ion programme is to produce matter at the
highest temperatures and densities attainable in the laboratory, and to study
its properties. This programme is expected to produce, in very small
quantities, primordial plasma of the type that filled the Universe when it was
about a microsecond old.
The normal matter of which we are made, and which constitutes all the
known visible matter in the Universe, is composed of the two lightest types of
quarks, the up and down quarks. Heavier, unstable quarks have been
discovered in cosmic-ray collisions and at accelerators, and the lightest of
these is the strange quark. Particles containing strange quarks have been
produced regularly in the laboratory for many decades, and are known to
decay on time scales of the order of a nanosecond, or faster. Such lifetimes are
characteristic of the weak interaction responsible for radioactivity, which
governs their decay. Some unstable particles containing two or three strange
quarks have also been observed. Particles including one strange quark have
been shown to bind to nuclei, the so-called hypernuclei, which are however
unstable and promptly decay, again with nanosecond time scales. Apart from
rapidly decaying nuclei with two particles each containing one strange quark
[11], no nuclei containing multiple strange quarks are known.
Strange quark matter is a hypothetical state of matter, which would consist of
large, roughly equal numbers of up, down and strange quarks. Hypothetical
small lumps of strange quark matter, having atomic masses comparable to
ordinary nuclei, are often referred to as strangelets. Most theoretical studies of
strangelets conclude that, if they exist, they must be unstable, decaying with a
typical strange-particle lifetime of around a nanosecond. In this case, any
production of strangelets would pose no risk. However, it has been
speculated that strange quark matter might weigh less than conventional
nuclear matter with the same number of up and down quarks, but not for
atomic numbers smaller than 10. In this very hypothetical case, such a
strangelet would be stable. It has been further speculated that, if produced,
strangelets could coalesce with normal matter and catalyze its conversion into
strange matter, thereby creating an ever-growing strangelet. This hypothetical
scenario underlies concerns about strangelet production at accelerators, which
were discussed previously in [8] and [1].
It is generally expected that any stable strangelet would have a positive
charge, in which case it would be repelled by ordinary nuclear matter, and
hence unable to convert it into strange matter [8], see [12], however. In some
model studies, one finds that negatively-charged strangelets can also exist,
but are unstable since the positively-charged states have lower energy [13].
However, there is no rigorous proof that the charge of a stable strangelet must
be positive, nor that a negatively-charged strangelet cannot be metastable, i.e.,
very long-lived. So, one should also consider the possibility of a negatively-
charged stable or very long-lived strangelet.
Prior to the start of the Relativistic Heavy-Ion Collider (RHIC), a study was
carried out [8] to assess hypothetical scenarios for the production of
strangelets in heavy-ion collisions. Additional arguments were given in [14],
and a reassessment of such a possibility was given in the 2003 Report of the
LHC CERN Safety Study Group [1]. We revisit here this topic in light of
recent advances in our understanding of the theory and experiment of heavy-
ion collisions. These enable us to update and strengthen the previous
conclusions about hypothetical scenarios based on strangelet production.
More details of our considerations on strangelet production at the LHC are
given in an Addendum [15].
The 2003 report summarized the status of direct experimental searches and of
theoretical speculations about hypothetical strangelet production mechanisms
[1]. More recently, additional direct upper limits on strangelet production
have been provided by experimental searches at RHIC [16] and among cosmic
rays [17], which have not yielded any evidence for the existence of strangelets.
In the near future, additional experimental information may be expected from
strangelet searches in samples of lunar soil and from particle detectors in
outer space [18].
On the theoretical side, the 2003 report considered three mechanisms for
strangelet production [1]: i) a thermal mechanism [3], in which particles are
produced as if from a heat bath in thermal equilibrium, ii) a coalescence
mechanism, in which particles produced in a heavy-ion collision might
combine at late times to form a strangelet, and iii) a distillation mechanism
[19], which was proposed as a specific model for strangelet production.
According to this last mechanism, a hot quark-gluon plasma with large net
baryon number is produced in heavy-ion collisions, and is enriched in
strangeness as it cools down by emitting predominantly particles containing
strange antiquarks.
No evidence has been found in the detailed study of heavy-ion collisions at
RHIC for an anomalous coalescence mechanism. In particular, the production
rate of light nuclei measured in central Au+Au collisions at RHIC [14], is
consistent with the coalescence rates, used in the 2003 Report of the LHC
CERN Safety Study Group [1] to rule out strangelet production. There is also
considerable experimental evidence against the distillation mechanism. For
this mechanism to be operational, the produced matter should have a long
lifetime and a large net nucleon density. However, experiments at RHIC
confirm the general expectations that the net nucleon density is small and
decreases at higher collision energies. Moreover, the plasma produced in the
collision is very short-lived, expanding rapidly at about half the velocity of
light, and falling apart within 10–23 seconds [20]. Furthermore, no
characteristic difference has been observed in the production of particles
containing strange quarks and antiquarks. Hence, a distillation mechanism
capable of giving rise to strangelet production is not operational in heavy-ion
collisions at RHIC, and this suggestion for strange-particle production has
been abandoned for the LHC. On the other hand, as reviewed below, RHIC
data strongly support models that describe particle production as emission
from a high-temperature heat bath [3].
If they exist, strangelets would be bound states that would be formed initially
with an atomic number comparable to that of normal nuclei. Like normal
nuclei, strangelets would also contain a significant baryon number. We know
from the basic principles of quantum mechanics that, for a strangelet to be
formed, its constituents must be assembled in a configuration that contains
less than its characteristic binding energy. If this were not the case, the forces
between the constituents would not be strong enough to hold them together,
and the strangelet would not form. As a consequence, strangelet formation is
less likely if the constituents have initially more kinetic energy, and
specifically if they emerge from a hotter system. Correspondingly, strangelet
production is less likely in a hotter system.
The energy needed to break up a strangelet is similar to that needed to break
up a normal nucleus, which is of the order of one to a few million electron
volts. Similar energies would be reached in a heat bath with a temperature of
ten to several tens of billions of degrees Celsius. However, heavy-ion
collisions are known to produce heat baths that are far hotter, reaching
temperatures exceeding 1 trillion degrees Celsius [3]. Basic thermodynamics
would require most strangelets to melt in such a heat bath, i.e., dissociate into
the known strange particles that decay within a nanosecond. For this reason,
the likelihood of strangelet production in relativistic heavy-ion collisions can
be compared to the likelihood of producing an icecube in a furnace.
The analogy of heavy-ion collisions with a particle furnace has been
supported by many detailed measurements in accelerator collisions of the
production of different types of particles, including those containing one, two
or three strange quarks. Fig. 2 shows one such piece of evidence: the relative
rates at which particles are produced in heavy-ion collisions at RHIC is in line
with a theoretical calculation assuming a furnace with a temperature around
1.6 trillion degrees [3]. All particle ratios are well-described, including rare
particles like the Omega baryon, which contains three strange quarks and
which – if compared to the most abundant particles such as pions - is
produced only at the per-mille level (see Fig. 2).
Fig. 2: The relative amounts of different particles and antiparticles produced at RHIC.
All the measurements (red points) agree very well with a simple thermal model (blue
lines) with an effective temperature around 1.6 trillion degrees, in line with
theoretical calculations, and a net nucleon (quark) density that is lower than in
previous, lower-energy experiments. The inset shows that the fraction of strange
quarks has saturated at the same density as up and down quarks. Figure taken from
[3].
The total number of heavy-ion collisions created at the LHC will be
comparable to the total number of heavy ion collision created at RHIC. The
LHC will be at least as hot a furnace as RHIC, in the sense that the systems
produced in heavy-ion collisions at the LHC will have an effective
temperature that is similar to that produced at RHIC. This is one factor that
makes strangelet production no more likely at the LHC than at RHIC.
Another major factor pointing in the same direction is that the net density of
nucleons, measured by the baryon number, will be lower at the LHC than at
RHIC. This is because the system produced in heavy-ion collisions at the LHC
is spread over a larger rapidity range, and the same total net baryon number
will be spread over a larger volume. This effect has already been seen at
RHIC, where the net density of nucleons is lower than in lower-energy
experiments, and this trend will continue at the LHC [3]. Since strangelets
require baryon number to be formed, this effect makes strangelet production
less likely at the LHC than at RHIC.
We conclude on general physical grounds that heavy-ion collisions at the
LHC are less likely to produce strangelets than the lower-energy heavy-ion
collisions already carried out in recent years at RHIC, just as strangelet
production at RHIC was less likely than in previous lower-energy
experiments carried out in the 1980s and 1990s [8].
Knowing that strangelet production at the LHC is less likely than at previous
lower-energy machines, we now review the arguments that strangelet
production in previous lower-energy experiments did not pose any
conceivable risk.
It has been shown that the continuing survival of the Moon under cosmic-ray
bombardment ensures that heavy-ion collisions do not pose any conceivable
threat via strangelet production [8]. This is because cosmic rays have a
significant component of heavy ions, as does the surface of the Moon. Since
the Moon, unlike planets such as the Earth, is not protected by an atmosphere,
cosmic rays hitting the Moon have produced heavy-ion collisions over
billions of years at energies that are comparable to or exceed those reached in
man-made experiments.
The conclusion reached in [8] required two well-motivated assumptions.
Since high-energy cosmic rays include many iron nuclei, which are also
prevalent in the Moon’s surface, it was assumed that the conditions reached
in iron-iron collisions are comparable to those reached in the collisions of gold
ions or lead ions that had been studied previously in the laboratory.
Secondly, since RHIC and LHC experiments take place in the centre-of-mass
reference frame, whereas in cosmic-ray collisions the centre-of-mass frame is
moving at high speed, it was necessary to make some assumption about the
velocity distribution of any strangelets produced. We recall that high-velocity
strangelets might well be broken up by lunar matter before becoming slow
enough to coalesce with it.
Since the appearance of [8], the RHIC heavy-ion programme has also studied
the collisions of the copper ions, which are closely comparable to iron-iron
collisions. The abundances of particles produced in these collisions are
described by the same thermal model of a particle furnace that accounts
successfully for particle production in gold-gold collisions. Moreover, the
velocity distributions of all particle species observed at RHIC are similar to or
broader than the distribution assumed in [8]. These observations support the
assumptions made in [8], and therefore strengthen their conclusions.
An independent safety argument, which does not require any assumption
about the velocity distribution of any hypothetical strangelets, has been given
in [21]. The rate of cosmic-ray heavy-ion collisions in interstellar space is
known. If these collisions produced any strangelets, these would have
accreted in stars and any large-scale coalescence would have resulted in
stellar explosions that have not been seen. This complementary argument
does, however, assume that any strangelets produced do not decay on a time
scale much shorter than that of star formation.
We close this section by summarizing that the successful description of
heavy-ion collisions as a particle furnace with a net density of baryons that
decreases at higher energies implies that strangelet production at the LHC is
less likely than at lower-energy machines [15]. The arguments given
previously for the safety of lower-energy collisions are strengthened by recent
observations at RHIC. Furthermore, we note that the analogy of the LHC with
a hot particle furnace will be monitored from the earliest days of heavy-ion
collisions at the LHC. A thousand heavy-ion collisions would already suffice
for a first test of the thermal model which describes heavy-ion collisions as a
particle furnace. This will be among the first data analyses done in the LHC
heavy-ion programme, and will immediately provide an experimental
confirmation of the basic assumptions on which the safety argument is based.

Thomas ::

Tej Bibliji naj bi torej brezprizivno verjeli, nanjo se sklicuješ?

Aha.

It is generally expected that any stable strangelet would have a positive
charge, in which case it would be repelled by ordinary nuclear matter, and
hence unable to convert it into strange matte


Potem je pa vse v redu, če je "generally expected". Potem pa kar na gas!

Sickos.
Man muss immer generalisieren - Carl Jacobi

Zgodovina sprememb…

  • spremenil: Thomas ()

imagodei ::

Tipično Thomas (hm, to bi skoraj lahko bil slogan ali blagovna znamka >:D)

Najprej zahteva vire, ko pa jih dobi in se ne vklapajo v njegov svetovni nazor, jih ne jebe.
- Hoc est qui sumus -

jype ::

Thomas> Potem je pa vse v redu, če je "generally expected". Potem pa kar na gas!

Bo treba prebrat celo reč. Jasno je, da negativno nabiti strangeleti, če morejo obstajati, ne morejo obstajati dlje kot nekaj nanosekund pri temperaturi, ob kateri se utegnejo pojaviti v LHC. V RHIC je bila možnost nastanka strangeletov (pozitivno ali negativno nabitih) zaradi nižje energije trkov večja - pa ni nastal noben.

Thomas> Tej Bibliji naj bi torej brezprizivno verjeli, nanjo se sklicuješ?

A naj raje verjamemo tvojemu že neštetokrat izkazanem neznanju? _Izmerili_ smo, da je tveganje zanemarljivo - ti pa trapaš o "nevarnosti, o kateri sploh ne vemo dovolj".

Thomas> Sickos.

Mene prav zanima, kdaj se s tako vero nameravaš vpisat med kreacioniste.

Thomas ::

Najprej zahteva vire, ko pa jih dobi in se ne vklapajo v njegov svetovni nazor, jih ne jebe.


Da je tale vir kredibilen, stavite svojo glavo in zraven še glavo vseh ljudi na Zemlji?

Pameten človek tega NE bi storil. Pameten človek bi bil vsaj skeptičen do tega, da je CERN nepotopljiv. Ne pa da kar podpiše bianco menico na

It is generally expected that any stable strangelet would have a positive charge, in which case it would be repelled by ordinary nuclear matter, and hence unable to convert it into strange matte


"Generally expected" je bilo že marsikaj, pa se je izkazalo za narobe.

_Izmerili_ smo, da je tveganje zanemarljivo - ti pa trapaš o "nevarnosti, o kateri sploh ne vemo dovolj".


Izmerili ste? No shit?

Nihče še ni izmeril realne nevarnosti za negativen strangelet (naprimer) v pogojih LHC-ja. To bodo probali v živo, z milijardami poskusnih zajčkov v kletkah. Pardon, ljudi, ne zajčkov.
Man muss immer generalisieren - Carl Jacobi

Zgodovina sprememb…

  • spremenil: Thomas ()

imagodei ::

Thomas,

zakaj sploh zahtevaš vire, če pravzaprav ti, jaz in mi vsi vemo, da jih boš vnaprej označil za nekredibilne. Nekako smešno je to, that's all I'm saying.

V tem primeru ga ni kredibilnega vira/linka/literature, ki bi te lahko prepričal, da je nevarnost zanemarljivo majhna.
- Hoc est qui sumus -

jype ::

Thomas> Da je tale vir kredibilen, stavite svojo glavo in zraven še glavo vseh ljudi na Zemlji?

Ja. Tudi tvojo glavo stavimo. Ker se pogovarjamo o verjetnosti, ti seveda lahko povsem upravičeno očitamo, da obstaja približno enaka možnost (manj kot 10^-30 napake), da se v trenutku, ko LHC-ja _ne bomo_ uporabili, konča vesolje.

Thomas> "Generally expected" je bilo že marsikaj, pa se je izkazalo za narobe.

Če je "generally expected", da bo imel strangelet pozitiven naboj, hkrati pa ni nobene možnosti, da bi negativno nabit strangelet preživel dovolj časa, da bi se zlil z navadnim jedrom v bližini, ker pri trenutni temperaturi prej razpade, potem ta "generally expected" premisa zgolj še malo zmanjša možnost nastanka čudne snovi "pod nič" (kolikor je bila eksperimentalno pokazana v RHIC). Čisto na koncu tudi piše, da se bo s postopnim večanjem energije trkov težkih jeder ionov lahko tudi z eksperimentalnimi podatki sproti preverjalo verjetnost nastanka takšnih delcev glede na produkte, ki jih bodo trki pridelali.

Ampak, ker tebe žene vera v znanost, ki je ne razumeš, ti moje pisanje ne bo pomenilo nič - zato naj bo moje pisanje zgolj vpogled v to znanost za druge, ki še niso prepričani v lastno nezmotljivost in univerzalno obveščenost.

Zgodovina sprememb…

  • spremenilo: jype ()
strani: 1 2 3


Vredno ogleda ...

TemaSporočilaOglediZadnje sporočilo
TemaSporočilaOglediZadnje sporočilo
»

Napadi na električna omrežja v Braziliji?

Oddelek: Novice / Varnost
292125 (1103) Matthai
»

Hekerski napadi na številne varnostne strokovnjake

Oddelek: Novice / Varnost
243120 (1333) riba1122
»

V Kiberpipi v novem tednu

Oddelek: Novice / Kiberpipa
61390 (1008) Fave
»

Hekerski napad na generator črnih lukenj (strani: 1 2 3 )

Oddelek: Novice / Omrežja / internet
11510374 (5320) schurda
»

Anatomija hekerskega napada

Oddelek: Novice / --Nerazporejeno--
192549 (1716) cryptozaver

Več podobnih tem