Data from the Planck telescope have confirmed beyond any reasonable doubt a theory of the quantum origin of structure in the Universe. What exactly happened after the Universe was born? Why did stars, planets and huge galaxies form?
These are the questions that concern Viatcheslav Mukhanov, a cosmologist at Ludwig-Maximilians-Universitaet (LMU) in Munich, an expert in the field of Theoretical Cosmology. He has used the notion of so-called quantum fluctuations to construct a theory that provides a precise picture of the crucial initial phase of the evolution of our Universe: Without the minimal variations in energy density that result from the tiny but unavoidable quantum fluctuations, one cannot account for the formation of stars, planets and galaxies that characterize the Universe we observe today.
“The Planck data confirm the basic predictions that quantum fluctuations are at the origin of all structures in the Universe,” said Jean-Loup Puget, Principal Investigator for the HFI-instrument on the Planck satellite. Mukhanov, who first published his model in 1981 and joined the Physics Faculty at LMU in 1997, said: “I couldn’t hope for a better verification of my theory.”
The Planck Consortium has published new analyses of data returned by the Planck Space Telescope that has measured the distribution of the cosmic microwave background radiation (CMB), which, in essence, tells us what the Universe looked like about 400,000 years after the Big Bang. These latest findings are in complete agreement with the predictions of Mukhanov’s theory – for example, his calculation of the value of the so-called spectral index of the initial inhomogeneities.
The idea that quantum fluctuations must have played a role in the very earliest phase of the history of the Universe is implicit in Heisenberg’s Uncertainty Principle, according to Mukhanov. Heisenberg showed that there is a specific limit to the precision with which the position and the momentum of a particle can be determined at any given moment. This in turn implies that the initial matter distribution will inevitably exhibit minute inhomogeneities in density.
Mukhanov’s calculations first demonstrated that such quantum fluctuations could give rise to density differences in the early Universe, which in turn could serve as seeds for the galaxies and their clusters. Indeed, without quantum fluctuations, whose nature and magnitude Mukhanov quantitatively characterized, the observed distribution of matter in the Universe would be inexplicable.
The latest study of the Planck datasets is more detailed and more informative than the preliminary analysis published about 2 years ago. It reveals with unprecedented precision the patterns imprinted by primordial fluctuations on the distribution of radiation in the young Universe. Thus, instruments such as the Planck telescope can record these dispatches from an unimaginably remote past encoded in the microwave radiation that is still propagating through space – 13.8 billion years later. And from this information the Planck team can reconstruct a detailed picture of the distribution of matter at the birth of our Universe.
The Daily Galaxy via Ludwig-Maximilians-Universitaet
Image credit: NASA/Hubble. The big, beautiful spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way.
November 22, 2015