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.
- 28 November 2011
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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.