Many of the most basic and important physical phenomena are determined by a set of “fundamental constants”, whose values are experimentally known to high accuracy. A key aspect is to know whether they are “universal constants”, i.e., whether they have always had the same value across the Universe and throughout its history. Here we made use of data from the ESPRESSO spectrograph on the Very Large Telescope (VLT) in order to determine the value of the fine structure constant 8 thousand million years ago (when the Universe was just 40% its current age) by measuring spectral transitions in a cloud at redshift z=1.15 caused by the absorption of radiation emitted by a more-distant quasar (HE0515-4414) located on the same line of sight. Through the measurement of the wavelengths of spectral transitions produced between energy levels involving the atomic fine structure, these measurements have confirmed a value for the fine structure constant that is fully consistent with Earth-based laboratory measurements, with a precision better than one part per million. This is one of the most precise and most reliable measurements of the fine structure constant at high redshift; thanks to the high sensitivity and spectral resolution power as well as the extraordinary wavelength calibration accuracy of ESPRESSO.
It may interest you
The gravitational force needed for the universe to evolve from when it was almost uniform, during the Big Bang, until galaxies, stars, and planets were formed is provided by the “dark matter”. But in spite of the essential role of this basic component, which is estimated to make up some 80% of the matter in the universe, scientists know virtually nothing about its nature, behaviour, and composition, which is one of the main challenges in current physics and cosmology. Aiming to give answers to these questions the researcher Diego Blas, Senior Lecturer in the Department of Physics of King’sAdvertised on
Research by the Dark Energy Survey (DES) collaboration, in which the Instituto de Astrofísica de Canarias (IAC) participates, has confirmed the presence of a supervoid, an extremely large region with a lower-than-average density of matter, in the constellation Eridanus. Its study could provide new clues to understanding the nature of dark energy. The result is published today in Monthly Notices of the Royal Astronomical Society. The possibility of mapping the largest structures in the Universe has always been an aspiration of astrophysics. After the meticulous charting of our cosmic backyardAdvertised on
An international team of astronomers, co-led by researchers from the Instituto de Astrofísica de Canarias (IAC), has confirmed the presence of a new planet orbiting Proxima Centauri, the closest star to the Solar System. It is the third planet detected in this star and one of the lowest mass planets ever discovered, with only a quarter of the mass of the Earth. The study, published today in the journal Astronomy & Astrophysics, uses observations made with the ESPRESSO spectrograph on the Very Large Telescope (VLT) at the European Southern Observatory (ESO) in Chile. Proxima Centauri is theAdvertised on