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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

Para que servem os ateus?

 

Coelhos = religiosos, raposas = ateus?

Estou achando que preciso correr para escrever o meu livro intitulado “Deus e Acaso”, baseado em postagens deste blog. Alguns dos temas do livro já estão sendo discutidos em papers recentes, parece que existe um interesse cada vez maior sobre o assunto. Ver por exemplo o artigo abaixo, que foi um target article em um número inteiro dedicado a discussões desse tipo na revista Religion, Brain & Behavior.

What are atheists for? Hypotheses on the functions of non-belief in the evolution of religion

DOI: 10.1080/2153599X.2012.667948

Dominic Johnsona*
pages 48-70

Version of record first published: 27 Apr 2012

Abstract

An explosion of recent research suggests that religious beliefs and behaviors are universal, arise from deep-seated cognitive mechanisms, and were favored by natural selection over human evolutionary history. However, if a propensity towards religious beliefs is a fundamental characteristic of human brains (as both by-product theorists and adaptationists agree), and/or an important ingredient of Darwinian fitness (as adaptationists argue), then how do we explain the existence and prevalence of atheists – even among ancient and traditional societies? The null hypothesis is that – like other psychological traits – due to natural variation among individuals in genetics, physiology, and cognition, there will always be a range of strengths of religious beliefs. Atheists may therefore simply represent one end of a natural distribution of belief. However, an evolutionary approach to religion raises some more interesting adaptivehypotheses for atheism, which I explore here. Key among them are: (1) frequency dependence may mean that atheism as a “strategy” is selected for (along with selection for the “strategy” of belief), as long as atheists do not become too numerous; (2) ecological variation may mean that atheism outperforms belief in certain settings or at certain times, maintaining a mix in the overall population; (3) the presence of atheists may reinforce or temper religious beliefs and behaviors in the face of skepticism, boosting religious commitment, credibility, or practicality in the group as a whole; and (4) the presence of atheists may catalyze the functional advantages of religion, analogous to the way that loners or non-participants can enhance the evolution of cooperation. Just as evolutionary theorists ask what religious beliefs are “for” in terms of functional benefits for Darwinian fitness, an evolutionary approach suggests we should also at least consider what atheists might be for.

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?

Mais um passo rumo ao Darwinismo Cosmológico

Why Our Universe Must Have Been Born Inside a Black Hole


Posted: 12 Jul 2010 09:10 PM PDT

A small change to the theory of gravity implies that our universe inherited its arrow of time from the black hole in which it was born.

“Accordingly, our own Universe may be the interior of a black hole existing in another universe.” So concludes Nikodem Poplawski at Indiana University in a remarkable paper about the nature of space and the origin of time.

The idea that new universes can be created inside black holes and that our own may have originated in this way has been the raw fodder of science fiction for many years. But a proper scientific derivation of the notion has never emerged.

Today Poplawski provides such a derivation. He says the idea that black holes are the cosmic mothers of new universes is a natural consequence of a simple new assumption about the nature of spacetime.

Poplawski points out that the standard derivation of general relativity takes no account of the intrinsic momentum of spin half particles. However there is another version of the theory, called the Einstein-Cartan-Kibble-Sciama theory of gravity, which does.

This predicts that particles with half integer spin should interact, generating a tiny repulsive force called torsion. In ordinary circumstances, torsion is too small to have any effect. But when densities become much higher than those in nuclear matter, it becomes significant. In particular, says Poplawski, torsion prevents the formation of singularities inside a black hole.

That’s interesting for a number of reasons. First, it has important implications for the way the Universe must have grown when it was close to its minimum size.

Astrophysicists have long known that our universe is so big that it could not have reached its current size given the rate of expansion we see now. Instead, they believe it grew by many orders of magnitude in a fraction of a second after the Big Bang, a process known as inflation.

The problem with inflation is that it needs an additional theory to explain why it occurs and that’s ugly. Poplawski’s approach immediately solves this problem. He says that torsion caused this rapid inflation.

That means the universe as we see it today can be explained by a single theory of gravity without any additional assumptions about inflation.

Another important by-product of Poplawski’s approach is that it makes it possible for universes to be born inside the event horizons of certain kinds of black hole. Here, torsion prevents the formation of a singularity but allows a HUGE energy density to build up, which leads to the creation of particles on a massive scale via pair production followed by the expansion of the new universe.

This is a Big Bang type event. “Such an expansion is not visible for observers outside the black hole, for whom the horizon’s formation and all subsequent processes occur after infinite time,” says Poplawski.

For this reason, the new universe is a separate branch of space time and evolves accordingly.

Incidentally, this approach also suggests a solution to another of the great problems of cosmology: why time seems to flow in one direction but not in the other, even though the laws of physics are time symmetric.

Poplawski says the origin of the arrow of time comes from the asymmetry of the flow of matter into the black hole from the mother universe. “The arrow of cosmic time of a universe inside a black hole would then be fixed by the time-asymmetric collapse of matter through the event horizon,” he says.

In other words, our universe inherited its arrow of time from its mother.

He says that daughter universes may inherit other properties from their mothers, implying that it may be possible to detect these properties, providing an experimental proof of his idea.

Theories of everything don’t get much more ambitious than this. Entertaining stuff!

Ref: arxiv.org/abs/1007.0587: Cosmology With Torsion – An Alternative To Cosmic Inflation


Computational and Biological Analogies for Understanding Fine-Tuned Parameters in Physics

(Submitted on 20 Feb 2010)

In this philosophical paper, we explore computational and biological analogies to address the fine-tuning problem in cosmology. We first clarify what it means for physical constants or initial conditions to be fine-tuned. We review important distinctions such as the dimensionless and dimensional physical constants, and the classification of constants proposed by Levy-Leblond. Then we explore how two great analogies, computational and biological, can give new insights into our problem. This paper includes a preliminary study to examine the two analogies. Importantly, analogies are both useful and fundamental cognitive tools, but can also be misused or misinterpreted. The idea that our universe might be modelled as a computational entity is analysed, and we discuss the distinction between physical laws and initial conditions using algorithmic information theory. Smolin introduced the theory of “Cosmological Natural Selection” with a biological analogy in mind. We examine an extension of this analogy involving intelligent life. We discuss if and how this extension could be legitimated. 
Keywords: origin of the universe, fine-tuning, physical constants, initial conditions, computational universe, biological universe, role of intelligent life, cosmological natural selection, cosmological artificial selection, artificial cosmogenesis.

Comments: 25 pages, Foundations of Science, in press
Subjects: General Physics (physics.gen-ph)
Cite as: arXiv:1002.3905v1 [physics.gen-ph]