Cosmology - Cosmic Microwave Background (CMB)

Cosmic Microwave Background (CMB)

The Cosmic Microwave Background (CMB) is the remnant of the hot and dense early phases of the Universe. Its blackbody spectrum peaks around 2 mm (150 GHz) and its intensity dominates the high Galactic latitude sky at all wavelengths from about 20 cm to about 500 µm. Soon after the its discovery, in 1965, it was realized that the density fluctuations that seeded all the structure seen today must have imprinted tiny anisotropies in the CMB temperature, first detected in 1992 by NASA's COBE satellite. The power spectrum of CMB anisotropies encodes detailed information on the key cosmological parameters. An impressive series of experiments, culminating in the presently flying NASA's Wilkinson Anisotropy Probe (WMAP), have led to determine that the universe is close to spatially flat, it is dominated by dark energy, accounting for about 70% of the present cosmic energy density, by dark matter comprising about 85% of the matter density, and that primordial fluctuations had a nearly scale-invariant spectrum, consistent with having emerged from a primordial inflationary phase. In the inflationary scenario, vacuum energy dominated the energy density of the universe during its first moments, driving an exponential expansion which stretched a microscopic patch to a size much larger than our visible universe and making its geometry flat to high accuracy.

Primordial inflation also allows us to put constrains on the origin and the statistical properties of the primordial perturbations. The tremendous inflationary expansion bridges the gap between the subatomic length scales, on which quantum fluctuations are generated, and astrophysical scales, relating the seeds of the structure we observe in the universe to quantum fluctuations originated some 10^(-35) seconds after the big bang. In other words, from CMB anisotropies, that are directly related to the primordial density fluctuations, we learn about physical processes occurring at extreme energies, unattainable in any conceivable accelerator on Earth. Thus studies of the CMB bring us to the deepest questions about the origin of the universe. Although the inflationary scenario provides an impressive set of answers, the underlying physics is not well understood, and we need to dig more deeply into the extraordinary wealth of information contained in CMB maps.The next step in this direction is the Planck satellite, developed by the European Space Agency as the definitive mission for the study of CMB temperature anisotropy on scales down to 5 arcmin and as big step forward towards all-sky measurements of CMB polarization. Within the international Planck Consortium, the Padova group is leading the "component separation" effort for the Planck Low Frequency Instrument. The aim of this effort is, on one side, the cleaning of the CMB maps produced by Planck in the frequency range 30 - 860 GHz from the astrophysical signals superposed on it, and, on the other side, the reconstruction, as accurately as possible, of each individual foreground component, which has its own astrophysical interest.

Cosmic Microwave Background (CMB) - PAST STUDIES

News – MEDIA INAF

Il notiziario online dell'Istituto Nazionale di Astrofisica
  • La stazione spaziale cinese TianGong 1 è ormai prossima al rientro incontrollato in atmosfera, previsto attorno alla prima metà di marzo. Ne parliamo con Alberto Buzzoni, coordinatore scientifico del progetto Prisma, la cui rete italiana di camere per lo studio delle meteore tenterà di seguire l’evento

  • Il satellite cinese Micius ha permesso di dimostrare la fattibilità concreta di un collegamento internet intercontinentale ultra-sicuro facendo comunicare Pechino con Graz, in Austria, attraverso un sistema di crittografia quantistica basato sulla trasmissione di un singolo fotone

  • Lo spettacolo ”Starlight”, opera teatrale sulla storia dell'astrofisica in Italia di e con Filippo Tognazzo, sarà per la prima volta a Milano il 27 e 28 gennaio al Pacta dei teatri durante il festival ”Scienza in scena Atto 1”

  • Quanto può essere massiccia una stella di neutroni? Lo ha stabilito Luciano Rezzolla, dell’Istituto di studi avanzati di Francoforte, combinando le osservazioni delle onde gravitazioni prodotte dalla fusione di un sistema binario di stelle di neutroni con le relazioni quasi-universali presentate dallo stesso autore nel 2016. Media Inaf lo ha intervistato

  • Uno studio internazionale, a cui ha partecipato Sandro Scandolo dell’Ictp di Trieste, ha identificato con precisione il processo attraverso il quale - dal quarzo sottoposto ad alte pressioni nel mantello terrestre - si forma la coesite. Questo minerale si origina anche a seguito di impatti meteorici, contribuendo quindi a identificare l’origine dei crateri

  • Un nuovo studio guidato da Antonino Petralia dell'Inaf di Palermo presenta i risultati di recenti simulazioni d’un evento di pioggia coronale, osservato il 4 novembre 2015, allo scopo di comprendere il meccanismo alla base del processo di frammentazione e ricaduta del plasma

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