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Nosso universo vai congelar como uma cerveja super-resfriada…

SCIENTIFIC METHOD / SCIENCE & EXPLORATION

Finding the Higgs? Good news. Finding its mass? Not so good.

“Fireballs of doom” from a quantum phase change would wipe out present Universe.

by  – Feb 19 2013, 8:55pm HB

A collision in the LHC’s CMS detector.

Ohio State’s Christopher Hill joked he was showing scenes of an impending i-Product launch, and it was easy to believe him: young people were setting up mats in a hallway, ready to spend the night to secure a space in line for the big reveal. Except the date was July 3 and the location was CERN—where the discovery of the Higgs boson would be announced the next day.

It’s clear the LHC worked as intended and has definitively identified a Higgs-like particle. Hill put the chance of the ATLAS detector having registered a statistical fluke at less than 10-11, and he noted that wasn’t even considering the data generated by its partner, the CMS detector. But is it really the one-and-only Higgs and, if so, what does that mean? Hill was part of a panel that discussed those questions at the meeting of the American Association for the Advancement of Science.

As theorist Joe Lykken of Fermilab pointed out, the answers matter. If current results hold up, they indicate the Universe is currently inhabiting what’s called a false quantum vacuum. If it were ever to reach the real one, its existing structures (including us), would go away in what Lykken called “fireballs of doom.”

We’ll look at the less depressing stuff first, shall we?

Zeroing in on the Higgs

Thanks to the Standard Model, we were able to make some very specific predictions about the Higgs. These include the frequency with which it will decay via different pathways: two gamma-rays, two Z bosons (which further decay to four muons), etc. We can also predict the frequency of similar looking events that would occur if there were no Higgs. We can then scan each of the decay pathways (called channels), looking for energies where there is an excess of events, or bump. Bumps have shown up in several channels in roughly the same place in both CMS and ATLAS, which is why we know there’s a new particle.

But we still don’t know precisely what particle it is. The Standard Model Higgs should have a couple of properties: it should be scalar and should have a spin of zero. According to Hill, the new particle is almost certainly scalar; he showed a graph where the alternative, pseudoscalar, was nearly ruled out. Right now, spin is less clearly defined. It’s likely to be zero, but we haven’t yet ruled out a spin of two. So far, so Higgs-like.

The Higgs is the particle form of a quantum field that pervades our Universe (it’s a single quantum of the field), providing other particles with mass. In order to do that, its interactions with other particles vary—particles are heavier if they have stronger interactions with the Higgs. So, teams at CERN are sifting through the LHC data, checking for the strengths of these interactions. So far, with a few exceptions, the new particle is acting like the Higgs, although the error bars on these measurements are rather large.

As we said above, the Higgs is detected in a number of channels and each of them produces an independent estimate of its mass (along with an estimated error). As of the data Hill showed, not all of these estimates had converged on the same value, although they were all consistent within the given errors. These can also be combined mathematically for a single estimate, with each of the two detectors producing a value. So far, these overall estimates are quite close: CMS has the particle at 125.8GeV, Atlas at 125.2GeV. Again, the error bars on these values overlap.

Oops, there goes the Universe

That specific mass may seem fairly trivial—if it were 130GeV, would you care? Lykken made the argument you probably should. But he took some time to build to that.

Lykken pointed out, as the measurements mentioned above get more precise, we may find the Higgs isn’t decaying at precisely the rates we expect it to. This may be because we have some details of the Standard Model wrong. Or, it could be a sign the Higgs is also decaying into some particles we don’t know about—particles that are dark matter candidates would be a prime choice. The behavior of the Higgs might also provide some indication of why there’s such a large excess of matter in the Universe.

But much of Lykken’s talk focused on the mass. As we mentioned above, the Higgs field pervades the entire Universe; the vacuum of space is filled with it. And, with a value for the Higgs mass, we can start looking into the properties of the Higgs filed and thus the vacuum itself. “When we do this calculation,” Lykken said, “we get a nasty surprise.”

It turns out we’re not living in a stable vacuum. Eventually, the Universe will reach a point where the contents of the vacuum are the lowest energy possible, which means it will reach the most stable state possible. The mass of the Higgs tells us we’re not there yet, but are stuck in a metastable state at a somewhat higher energy. That means the Universe will be looking for an excuse to undergo a phase transition and enter the lower state.

What would that transition look like? In Lykken’s words, again, “fireballs of doom will form spontaneously and destroy the Universe.” Since the change would alter the very fabric of the Universe, anything embedded in that fabric—galaxies, planets, us—would be trashed during the transition. When an audience member asked “Are the fireballs of doom like ice-9?” Lykken replied, “They’re even worse than that.”

Lykken offered a couple of reasons for hope. He noted the outcome of these calculations is extremely sensitive to the values involved. Simply shifting the top quark’s mass by two percent to a value that’s still within the error bars of most measurements, would make for a far more stable Universe.

And then there’s supersymmetry. The news for supersymmetry out of the LHC has generally been negative, as various models with low-mass particles have been ruled out by the existing data (we’ll have more on that shortly). But supersymmetry actually predicts five Higgs particles. (Lykken noted this by showing a slide with five different photos of Higgs taken at various points in his career, in which he was “differing in mass and other properties, as happens to all of us.”) So, when the LHC starts up at higher energies in a couple of years, we’ll actually be looking for additional, heavier versions of the Higgs.

If those are found, then the destruction of our Universe would be permanently put on hold. “If you don’t like that fate of the Universe,” Lykken said, “root for supersymmetry”

Planetas extra-solares, Kepler 62 e o Paradoxo de Fermi local

Conforme aumentam o número de planetas extra-solares descobertos, também aumentamos vínculos sobre as previsões do modelo de percolação galática (Paradoxo de Fermi Local).
A previsão é que, se assumirmos que Biosferas Meméticas (Biosferas culturais ou Tecnosferas) são um resultado provável de Biosferas Genéticas, então devemos estar dentro de uma região com pucos planetas habitáveis. Pois se existirem planetas habitados (por seres inteligentes) por perto, com grande probabilidade eles são bem mais avançados do que nós, e já teriam nos colonizado.
Como isso ainda não ocorreu (a menos que se acredite nas teorias de conspiração dos ufólogos e nas teorias de Jesus ET, deuses astronautas etc.), segue que quanto mais os astronomos obtiverem dados, mais ficará evidente que nosso sistema solar é uma anomalia dentro de nossa vizinhança cósmica (1000 anos-luz?), ou seja, não podemos assumir o Princípio Copernicano em relação ao sistema solar: nosso sistema solar não é tipico em nossa vizinhança.  Bom, pelo menos, essa conclusão está batendo com os dados coletados até hoje…
Assim, é possível fazer a previsão de que uma maior análise dos planetas Kepler 62-e e Kepler 62-f revelará que eles não possuem uma atmosfera com oxigênio ou metano, sinais de um planeta com biosfera.

Persistence solves Fermi Paradox but challenges SETI projects

Osame Kinouchi (DFM-FFCLRP-Usp)
(Submitted on 8 Dec 2001)

Persistence phenomena in colonization processes could explain the negative results of SETI search preserving the possibility of a galactic civilization. However, persistence phenomena also indicates that search of technological civilizations in stars in the neighbourhood of Sun is a misdirected SETI strategy. This last conclusion is also suggested by a weaker form of the Fermi paradox. A simple model of a branching colonization which includes emergence, decay and branching of civilizations is proposed. The model could also be used in the context of ant nests diffusion.

03/05/2013 – 03h10

Possibilidade de vida não se resume a planetas similares à Terra, diz estudo

SALVADOR NOGUEIRA
COLABORAÇÃO PARA A FOLHA

Com as diferentes composições, massas e órbitas possíveis para os planetas fora do Sistema Solar, a vida talvez não esteja limitada a mundos similares à Terra em órbitas equivalentes à terrestre.

Editoria de arte/Folhapress

Essa é uma das conclusões apresentada por Sara Seager, do MIT (Instituto de Tecnologia de Massachusetts), nos EUA, em artigo de revisão publicado no periódico “Science“, com base na análise estatística dos cerca de 900 mundos já detectados ao redor de mais de 400 estrelas.

Seager destaca a possível existência de planetas cuja atmosfera seria tão densa a ponto de preservar água líquida na superfície mesmo a temperaturas bem mais baixas que a terrestre. Read more [+]

Palestra no Instituto de Estudos Avançados (RP) sobre Ciência e Religião

 

sexta-feira, 9 de novembro de 2012

Ciência e Religião: quatro perspectivas

Escrito por 

Data e Horário: 26/11 às 14h30
Local: Salão de Eventos do Centro de Informática de Ribeirão Preto – CIRP/USP (localização)

O evento, que será apresentado por Osame Kinouchi, discutirá quatro diferentes visões sobre a interação entre Ciência e Religião: o conflito, a separação, o diálogo e a integração. Examinando as fontes de conflito recentes (Culture Wars), o professor sugere que elas têm origem no Romantismo Anticientífico, religioso ou laico.

Segundo Osame, a ideia de separação entre os campos Religioso e Científico já não parece ser viável devido aos avanços da Ciência em tópicos antes considerados metafísicos, tais como as origens do Universo (Cosmologia), da Vida (Astrobiologia), da Mente (Neurociências) e mesmo das Religiões (Neuroteologia, Psicologia Evolucionária e Ciências da Religião).
A palestra mostrará também que tentativas de integração forçada ou prematura entre Religião e Ciência correm o risco de derivar para a Pseudociência. Sendo assim, na visão do professor, uma posição mais acadêmica de diálogo de alto nível pode ser um antídoto para uma polarização cultural ingênua entre Ateísmo e Religiosidade.

Vídeo do evento

Seleção Artificial Cosmológica: primeiras referências

Tive a mesma ideia em 1995, mas não publiquei. Sexta feira passada, achei numa pasta abandonada os escritos que estão digitalizados aqui.  Por um erro de memória, confundi Lee Smolin (em inglês e mais completo aqui) com Sidney Coleman.

Meduso-anthropic principle

The meduso-anthropic principle is a quasi-organic universe theory originally proposed by mathematician and quantum gravity scholar Louis Crane in 1994.

Contents

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Universes and black holes as potential life cycle partners

Crane’s MAP is a variant of the hypothesis of cosmological natural selection (fecund universes), originally proposed by cosmologist Lee Smolin (1992). It is perhaps the first published hypothesis of cosmological natural selection with intelligence (CNS-I), where intelligence plays some proposed functional role in universe reproduction. It is also an interpretation of the anthropic principle (fine-tuning problem). The MAP suggests the development and life cycle of the universe is similar to that of Corals and Jellyfish, in which dynamic Medusa are analogs for universal intelligence, in co-evolution and co-development with sessile Polyp generations, which are analogs for both black-holes and universes. In the proposed life cycle, the Universe develops intelligent life and intelligent life produces new baby universes. Crane further speculates that our universe may also exist as a black hole in a parallel universe, and extraterrestrial life there may have created that black hole.

Crane’s work was published in 1994 as a preprint on arXiv.org. In 1995, in an an article in QJRAS, emeritus cosmologist Edward Harrison (1919-2007) independently proposed that the purpose of intelligent life is to produce successor universes, in a process driven by natural selection at the universal scale. Harrison’s work was apparently the first CNS-I hypothesis to be published in a peer-reviewed journal.

Why future civilizations might create black holes

Crane speculates that successful industrial civilizations will eventually create black holes, perhaps for scientific research, for energy production, or for waste disposal. After the hydrogen of the universe is exhausted civilizations may need to create black holes in order to survive and give their descendants the chance to survive. He proposes that Hawking radiation from very small, carefully engineered black holes would provide the energy enabling civilizations to continue living when other sources are exhausted.

Philosophical implications

According to Crane, Harrison, and other proponents of CNS-I, mind and matter are linked in an organic-like paradigm applied at the universe scale. Natural selection in living systems has given organisms the imperative to survive and reproduce, and directed their intelligence to that purpose. Crane’s MAP proposes a functional purpose for intelligence with respect to universe maintenance and reproduction. Universes of matter produce intelligence, and intelligent entities are ultimately driven to produce new universes.

See also

References

Os deuses de Richard Dawkins

File:NASA child bubble exploration.jpgMy personal theology is described in the Gifford lectures that I gave at Aberdeen in Scotland in 1985, published under the title, Infinite In All Directions. Here is a brief summary of my thinking. The universe shows evidence of the operations of mind on three levels. The first level is elementary physical processes, as we see them when we study atoms in the laboratory. The second level is our direct human experience of our own consciousness. The third level is the universe as a whole. Atoms in the laboratory are weird stuff, behaving like active agents rather than inert substances. They make unpredictable choices between alternative possibilities according to the laws of quantum mechanics. It appears that mind, as manifested by the capacity to make choices, is to some extent inherent in every atom. The universe as a whole is also weird, with laws of nature that make it hospitable to the growth of mind. I do not make any clear distinction between mind and God. God is what mind becomes when it has passed beyond the scale of our comprehension. God may be either a world-soul or a collection of world-souls. So I am thinking that atoms and humans and God may have minds that differ in degree but not in kind. We stand, in a manner of speaking, midway between the unpredictability of atoms and the unpredictability of God. Atoms are small pieces of our mental apparatus, and we are small pieces of God’s mental apparatus. Our minds may receive inputs equally from atoms and from God. This view of our place in the cosmos may not be true, but it is compatible with the active nature of atoms as revealed in the experiments of modern physics. I don’t say that this personal theology is supported or proved by scientific evidence. I only say that it is consistent with scientific evidence.  Freeman Dyson

Parece que Dawkins está rumando para uma posição similar à de Gardner, Clément Vidal e outros da comunidade Evo-Devo Universe.

Human Gods

After two hours of conversation, Professor Dawkins walks far afield. He talks of the possibility that we might co-evolve with computers, a silicon destiny. And he’s intrigued by the playful, even soul-stirring writings of Freeman Dyson, the theoretical physicist.

In one essay, Professor Dyson casts millions of speculative years into the future. Our galaxy is dying and humans have evolved into something like bolts of superpowerful intelligent and moral energy.

Doesn’t that description sound an awful lot like God?

“Certainly,” Professor Dawkins replies. “It’s highly plausible that in the universe there are God-like creatures.”

He raises his hand, just in case a reader thinks he’s gone around a religious bend. “It’s very important to understand that these Gods came into being by an explicable scientific progression of incremental evolution.”

Could they be immortal? The professor shrugs.

“Probably not.” He smiles and adds, “But I wouldn’t want to be too dogmatic about that.”

O melhor livro de divulgação científica que encontrei em quarenta anos de leituras

Depois escrevo minha resenha…

A REALIDADE OCULTA – Universos paralelos e as leis profundas do cosmo
Brian Greene
R$ 59,00 Comprar
R$ 39,00 E-Book
Indique Comente
É necessário estar logado para utilizar este recurso. Acompanhe

Meio século atrás, os cientistas encaravam com ironia a possibilidade de existirem outros universos além deste que habitamos. Tal hipótese não passava de um delírio digno de Alice no País das Maravilhas – e que, de todo modo, jamais poderia ser comprovada experimentalmente. Os desafios propostos pela Teoria da Relatividade e pela física quântica para o entendimento de nosso próprio universo já eram suficientemente complexos para ocupar gerações e gerações de pesquisadores. Entretanto, diversos estudos independentes entre si, conduzidos por cientistas respeitados em suas áreas de atuação – teoria das cordas, eletrodinâmica quântica, teoria da informação -, começaram a convergir para o mesmo ponto: a existência de universos paralelos – o multiverso – não só é provável como passou a ser a explicação mais plausível para diversos enigmas cosmológicos.
Em A realidade oculta, Brian Greene – um dos maiores especialistas mundiais em cosmologia e física de partículas – expõe o fantástico desenvolvimento da física do multiverso ao longo das últimas décadas. O autor de O universo elegante passa em revista as diferentes teorias sobre os universos paralelos a partir dos fundamentos da relatividade e da mecânica quântica. Por meio de uma linguagem acessível e valendo-se de numerosas figuras explicativas, Greene orienta o leitor pelos labirintos da realidade mais profunda da matéria e do pensamento.

“Se extraterrestres aparecessem amanhã e pedissem para conhecer as capacidades da mente humana, não poderíamos fazer nada melhor que lhes oferecer um exemplar deste livro.” – Timothy Ferris, New York Times Book Review

Uma prova matemática de que o Universo teve um início?

Mathematics of Eternity Prove The Universe Must Have Had A Beginning — Part II

Heavyweight cosmologists are battling it out over whether the universe had a beginning. And despite appearances, they may actually agree

11 comments

THE PHYSICS ARXIV BLOG

Friday, April 27, 2012

Earlier this week, Audrey Mithani and Alexander Vilenkin at Tufts University in Massachusetts argued that the mathematical properties of eternity prove that the universe must have had a beginning.

Today, another heavyweight from the world of cosmology weighs in with an additional argument. Leonard Susskind at Stanford University in California, says that even if the universe had a beginning, it can be thought of as eternal for all practical purposes.

Susskind is good enough to give a semi-popular version of his argument:

“To make the point simply, imagine Hilbertville, a one-dimensional semi-infinite city, whose border is at x = 0: The population is infinite and uniformly fills the positive axis x > 0: Each citizen has an identical telescope with a finite power. Each wants to know if there is a boundary to the city. It is obvious that only a finite number of citizens can see the boundary at x = 0. For the infinite majority the city might just as well extend to the infinite negative axis.

Thus, assuming he is typical, a citizen who has not yet studied the situation should bet with great confidence that he cannot detect a boundary. This conclusion is independent of the power of the telescopes as long as it is finite.”

He goes on to discuss various thermodynamic arguments that suggest the universe cannot have existed for ever. The bottom line is that the inevitable increase of entropy over time ensures that a past eternal universe ought to have long since lost any semblance of order. Since we can see order all around us, the universe cannot be eternal in the past.

He finishes with this: “We may conclude that there is a beginning, but in any kind of inflating cosmology the odds strongly (infinitely) favor the beginning to be so far in the past that it is eff ectively at minus infinity.”

Susskind is a big hitter: a founder of string theory and one of the most influential thinkers in this area. However, it’s hard to agree with his statement that this argument represents the opposing view to Mithani and Vilenkin’s.

His argument is equivalent to saying that the cosmos must have had a beginning even if it looks eternal in the past, which is rather similar to Mithani and Vilenkin’s view. The distinction that Susskind does make is that his focus is purely on the practical implications of this–although what he means by ‘practical’ isn’t clear.

That the universe did or did not have a beginning is profoundly important from a philosophical point of view, so much so that a definitive answer may well have practical implications for humanity.

But perhaps the real significance of this debate lies elsewhere. The need to disagree in the face of imminent agreement probably tells us more about the nature of cosmologists than about the cosmos itself.

Ref: arxiv.org/abs/1204.5385: Was There a Beginning?

Estamos em um período revolucionário na Física? Neutrinos anômalos, anti-mesons anômalos e Multiverso como ortodoxia

Achei um blog muito bom para seguir o desdobramento da controvérsia sobre os neutrinos aparentemente superluminais:

Of Particular Significance

Conversations About Science with Theoretical Physicist Matt Strassler

Cientistas famosos como Lee Smolin comentam neste blog. Acho que vou começar a seguir o caso dos neutrinos apenas por este blog e evitar as notícias de jornal e de revistas de divulgação. O blog também comenta sobre as tentativas de explicaçãoda anomalia que estão saindo no ArXiv. O status atual, segundo Matt, é que mesmo o paper do ICARUS e o paper de CG não constituem uma refutação dos resultados do OPERA, pois usam pressupostos teóricos que podem estar errados caso a relação de dispersão dos neutrinos seja outra que a da relatividade restrita. E, ao contrário de Jorge Stolfi, Matt não acredita que o problema com o OPERA tem a ver com as medidas de distância e tempo.

Neutrinos and multiverses: a new cosmology beckons

You wait decades for discoveries that could revolutionise physics, then three come along at once

“THE universe is not only queerer than we suppose, but queerer than we can suppose,” as geneticist J. B. S. Haldane once remarked. In recent decades, physicists have done their best to prove Haldane wrong, by supposing some very queer universes indeed.

Their speculations may seem fantastical, but they are well motivated. Physics poses some formidable questions that we are so far unable to answer. Why is the universe dominated by matter not antimatter? Why does our universe appear to be “fine-tuned” with just the right properties to give rise to galaxies, stars, planets, life and physicists?

The existing edifice of physics, built upon the twin foundations of general relativity and quantum mechanics, is clearly in need of renovation. We have been waiting for years for cracks to appear that might tell us how to go about it. But up to now, nature has remained stubbornly unmoved.

In the past few weeks, however, promising cracks have opened up. In September came stunning news of neutrinos travelling faster than the speed of light. Sceptics withheld judgement but now a new analysis has affirmed the initial result (see “More data shows neutrinos still faster than light”). We still await independent verification – doubts have already been cast – but if it holds up the implications are enormous, opening the door to a new and very different picture of the cosmos.

No less tantalising is a report that particles called mesons decay differently from their antimatter counterparts, anti-mesons (see “LHC antimatter anomaly hints at new physics”). If this result stands up, it would go a long way towards explaining why we have more matter than antimatter. More importantly, it would prise open the standard model of particle physics – which cannot explain the result – and point the way to yet more new physics.

The widest crack of all concerns a theory once considered outlandish but now reluctantly accepted as the orthodoxy. Almost everything in modern physics, from standard cosmology and quantum mechanics to string theory, points to the existence of multiple universes – maybe 10500 of them, maybe an infinite number (see “The ultimate guide to the multiverse”).

If our universe is just one of many, that solves the “fine-tuning” problem at a stroke: we find ourselves in a universe whose laws are compatible with life because it couldn’t be any other way. And that would just be the start of a multiverse-fuelled knowledge revolution.

Conclusive evidence may be close at hand. Theorists predict that our universe might once have collided with others. These collisions could have left dents in the cosmic microwave background, the universe’s first light, which the European Space Agency’s Planck satellite is mapping with exquisite precision. The results are eagerly awaited, and could trigger a revolution not unlike the ones unleashed by Copernicus’s idea that the Earth is not the centre of the solar system and Edwin Hubble’s discovery that our galaxy is just one among many in an expanding universe.

These are exciting, possibly epoch-making, times. Our understanding of the universe stands on the brink of being remade once again. The universe may indeed be queerer than we can suppose, but that was never going to stop us from trying.

Universo espelho

Seven (and a half) reasons to believe in Mirror Matter: From neutrino puzzles to the inferred Dark matter in the Universe

R. Foot
(Submitted on 16 Feb 2001 (v1), last revised 2 Mar 2001 (this version, v2))

Parity and time reversal are obvious and plausible candidates for fundamental symmetries of nature. Hypothesising that these symmetries exist implies the existence of a new form of matter, called mirror matter. The mirror matter theory (or exact parity model) makes four main predictions: 1) Dark matter in the form of mirror matter should exist in the Universe (i.e. mirror galaxies, stars, planets, meteoroids…), 2) Maximal ordinary neutrino – mirror neutrino oscillations if neutrinos have mass, 3) Orthopositronium should have a shorter effective lifetime than predicted by QED (in “vacuum” experiments) because of the effects of photon-mirror photon mixing and 4) Higgs production and decay rate should be 50% lower than in the standard model due to Higgs mirror – Higgs mixing (assuming that the seperation of the Higgs masses is larger than their decay widths). At the present time there is strong experimental/observational evidence supporting the first three of these predictions, while the fourth one is not tested yet because the Higgs boson, predicted in the standard model of particle physics, is yet to be found. This experimental/observational evidence is rich and varied ranging from the atmospheric and solar neutrino deficits, MACHO gravitational microlensing events, strange properties of extra-solar planets, the existence of “isolated” planets, orthopositronium lifetime anomaly, Tunguska and other strange “meteor” events including perhaps, the origin of the moon. The purpose of this article is to provide a not too technical review of these ideas along with some new results.

Comments: minor changes, latex, about 15p
Subjects: Astrophysics (astro-ph); High Energy Physics – Experiment (hep-ex); High Energy Physics – Phenomenology (hep-ph); High Energy Physics – Theory (hep-th)
Journal reference: ActaPhys.Polon.B32:2253-2270,2001
Cite as: arXiv:astro-ph/0102294v2

O Biocosmo Inteligente de Isaac Asimov

Sim, eu confesso. A minha teoria do Demiurgo e muito provavelmente a teoria do Biocosmo de Gardner foram inspiradas diretamente neste clássico conto do Asimov. É curioso que Asimov, um expoente do movimento cético, tenha dado um contraexemplo que refuta completamente a ideia de que a única posição compatível com a ciência seja a filosofia de baixa serotonina de Monod e Weinberg, de um Universo que emerge do Acaso, sem propósito e hostil a Vida. Asimov iniciou a terceira via entre o Teísmo e o Ateísmo.

Isaac Asimov – A Última Pergunta

Postado às 17:48:00 por Vindemiatrix

Aos leitores e, mais enfaticamente, aos amigos que se dedicam a perder um pouco de tempo por aqui, recomendo com o maior prazer a leitura do conto a seguir de Isaac Asimov, na tradução de Luiz Carlos Damasceno Jr.

As imagens criadas por Asimov são de encher a imaginação, as soluções para cada problema apresentado e o desfecho são esplêndidos. Meu dia vai ser melhor só por causa dele.

Isaac Asimov – A Última Pergunta

A última pergunta foi feita pela primeira vez, meio que de brincadeira, no dia 21 de maio de 2061, quando a humanidade dava seus primeiros passos em direção à luz. A questão nasceu como resultado de uma aposta de cinco dólares movida a álcool, e aconteceu da seguinte forma… Read more [+]

Tempos revolucionários na Física

Nos tempos de estudante sempre reverenciávamos os tempos heróicos da Mecânica Quântica e a coragem de seus fundadores. Mas será que realmente gostariamos de viver naquela época de confusão e queda de paradigmas centrais da física classica? Ou será que seriamos mais conservadores e céticos, esperando ver (confirmações definitivas ou um consenso científico) para crer em vez de acreditar que realmente uma nova física estava surgindo?

Roque propôs que se fizesse um estudo estatistico dos papers do ArXiv sobre os neutrinos superluminais. Pelo que vi até agora, dos 113 artigos sobre o assunto no repositorio, não tem nenhum de algum fisico brasileiro. A equipe de fisicos brasileiros que vai acompanhar o experimento MINOS em 2013 já anunciou que é cetica. 

Será que os brasileiros, por herança cultural lusitana, seriam mais conservadores? Cadê a tão propalada criatividade do brasileiro?  

Essa noticia que saiu agora explicaria o ajuste fino de alpha em nossas redondezas. Se alpha varia continuamente, talvez estivessemos em uma regiao critica de transicao: será que o nosso universo é critico e está na borda de uma transicao de fase entre duas regioes, como no caso de uma rede onde um gradiente de p (num modelo de percolacao)  produz p=p-c na borda entre uma regiao percolante e uma regiao nao percolante?

http://www.dailymail.co.uk/sciencetech/article-2056018/Laws-physics-change-depending-universe.html

Laws of physics ‘are different’ depending on where you are in the universe

  • Laws we know may be ‘like local by-laws’ say scientists
  • Hints universe is bigger than we think – possibly infinite
  • Other parts of the universe may be hostile to life

By ROB WAUGH

Last updated at 12:36 PM on 1st November 2011

The quasar ULAS J1120+0641: Scientists measured the light from distant quasars for the 'signatures' of metal atoms in between us and the distant galactic nuclei - they found that the measurements were different from similar ones on Earth

The quasar ULAS J1120+0641: Scientists measured the light from distant quasars for the ‘signatures’ of metal atoms in between us and the distant galactic nuclei – they found that the measurements were different from similar ones on Earth

The laws of physics may not be as set in stone as previously imagined.

One of the laws of nature seems to vary depending on where in the universe you are, research suggests.

The new analysis of data from Hawaii’s Keck telescope and Chile’s Extremely Large Telescope, could have profound implications for our understanding of the universe.

The ‘constancy’ of physics is one of the most cherished principles in science – but the scientists say that the ‘laws’ we know may be the galactic equivalent of ‘local by-laws’ and things may work quite differently elsewhere.

The discovery – if true – violates one of the underlying principles of Einstein’s theory of General Relativity, and has profound implications for our understanding of space and time.

The findings could mean that the universe is far bigger than we thought – possibly even infinite.

It also means that in other parts of the universe, the laws of physics might be hostile to life – whereas in our small part of it, they seem fine-tuned to supporting it. 

Research carried out at the University of New South Wales (UNSW), Swinburne University of Technology and the University of Cambridge found that one of the four known fundamental forces, electromagnetism – measured by the so-called fine-structure constant and denoted by the symbol ‘alpha’ – seems to vary across the Universe.

The two telescopes at the W.M. Keck Observatory on Mauna Kea on the Big Island of Hawaii. Scientists used data from these, and from the Extremely Large Telescope in Chile to search 300 distant galaxies

The two telescopes at the W.M. Keck Observatory on Mauna Kea on the Big Island of Hawaii. Scientists used data from these, and from the Extremely Large Telescope in Chile to search 300 distant galaxies

The researchers looked at light from distant quasars – huge, bright objects that outshine their host galaxies – to see how the light was absorbed by metallic atoms such as chromium, iron, nickel and zinc on its billion-year journey to us.

The researchers looked at 300 distant galaxies. The experiment found that the atoms in space behaved differently from ones on earth.

‘The results astonished us,’ said Professor Webb. ‘In one direction – from our location in the Universe – alpha gets gradually weaker, yet in the opposite direction it gets gradually stronger.’

‘The discovery, if confirmed, has profound implications for our understanding of space and time and violates one of the fundamental principles underlying Einstein’s General Relativity theory,’ Dr King added.

The scientists used distant quasars - huge, bright galactic nuclei - to 'illuminate' metal atoms in between them and earth. Analysing the light found that they behaved differently from atoms on Earth

The scientists used distant quasars – huge, bright galactic nuclei – to ‘illuminate’ metal atoms in between them and earth. Analysing the light found that they behaved differently from atoms on Earth

The first hints that alpha might not be constant came a decade ago when Professor John Webb and other colleagues at UNSW and elsewhere, analysed observations from the Keck Observatory, in Hawaii. Those observations were restricted to one broad area in the sky.

However, now Webb and colleagues have doubled the number of observations and measured the value of alpha in about 300 distant galaxies, all at huge distances from Earth, and over a much wider area of the sky.

The new observations were obtained using the European Southern Observatory’s ‘Very Large Telescope’ in Chile.

‘Such violations are actually expected in some more modern ‘Theories of Everything’ that try to unify all the known fundamental forces, said Professor Flambaum.

‘The smooth continuous change in alpha may also imply the Universe is much larger than our observable part of it, possibly infinite.’

‘Another currently popular idea is that many universes exist, each having its own set of physical laws,’ Dr Murphy said. ‘Even a slight change in the laws of Nature means they weren’t ‘set in stone’ when our Universe was born.

‘The laws of Nature you see may depend on your “space-time address” – when and where you happen to live in the Universe.’

Professor Webb said these new findings also offer a very natural explanation for a question that puzzled scientists for decades – why do the laws of physics seem to be so finely-tuned for the existence of life?

‘The answer may be that other regions of the Universe are not quite so favourable for life as we know it, and that the laws of physics we measure in our part of the Universe are merely ‘local by-laws’, in which case it is no particular surprise to find life here,’ he said.

Read more: http://www.dailymail.co.uk/sciencetech/article-2056018/Laws-physics-change-depending-universe.html#ixzz1ecjm6rEb

Nosso Universo é um bode castrado?

The F-Landscape: Dynamically Determining the Multiverse

Tianjun LiJames A. MaxinDimitri V. NanopoulosJoel W. Walker
(Submitted on 1 Nov 2011)

We evolve our Multiverse Blueprints to characterize our local neighborhood of the String Landscape and the Multiverse of plausible string, M- and F-theory vacua. Building upon the tripodal foundations of i) the Flipped SU(5) Grand Unified Theory (GUT), ii) extra TeV-Scale vector-like multiplets derived out of F-theory, and iii) the dynamics of No-Scale Supergravity, together dubbed No-Scale F-SU(5), we demonstrate the existence of a continuous family of solutions which might adeptly describe the dynamics of distinctive universes. This Multiverse landscape of F-SU(5) solutions, which we shall refer to as the F-Landscape, accommodates a subset of universes compatible with the presently known experimental uncertainties of our own universe. We show that by secondarily minimizing the minimum of the scalar Higgs potential of each solution within the F-Landscape, a continuous hypervolume of distinct minimum minimorum can be engineered which comprise a regional dominion of universes, with our own universe cast as the bellwether. We conjecture that an experimental signal at the LHC of the No-Scale F-SU(5) framework’s applicability to our own universe might sensibly be extrapolated as corroborating evidence for the role of string, M- and F-theory as a master theory of the Multiverse, with No-Scale supergravity as a crucial and pervasive reinforcing structure.

Comments: 15 Pages, 7 Figures, 1 Table
Subjects: High Energy Physics – Phenomenology (hep-ph); Cosmology and Extragalactic Astrophysics (astro-ph.CO); High Energy Physics – Theory (hep-th)
Report number: ACT-18-11; MIFPA-11-49
Cite as: arXiv:1111.0236v1 [hep-ph]

FRIDAY, NOVEMBER 5, 2010

“bellweather”

Thanks to my last post,  I found a financial word of the day email and subscribed to it. Couldn’t hurt, I thought. “Bellweather” was the very first one, which did not, shall we say, instill confidence. In one of my rare moments of non-ignorance, I actually know that the word is “bellwether”, not “bellweather”. I know this almost exclusively because I read the Connie Willis book of the same name. The book is not her best (I’d say that honor might go to To Say Nothing of the Dog or Doomsday Book, though friends report that her latest ones, Black Out and it’s sequel, the just released All Clear, about WWII England are up to that high bar.) Bellwether, though, is really good in its exploration of its title concept.

The bellwether is, to my understanding, the sheep that leads the drift of the flock. As a metaphor,  it’s maybe something like the trendsetter, or the avant garde. Willis’s novel is partly about trying to figure out about how the bellwether is selected. I think I’ll avoid spoilers around this one, as at the very least, there is a very interesting hypothesis proposed about this. Read more [+]