During the coming five years, Nicolaus Copernicus University (NCU) astronomers and colleagues at other Polish institutes will survey millions of stars in our Galaxy, the Milky Way, and millions of galaxies at distances from us of up to about a quarter of the way to the edge of the observable Universe. They will do this together with other astronomers from around Europe and Australia using the 4-metre Multi-Object Spectroscopy Telescope (4MOST).
The Polish 4MOST consortium, led by NCU and including the Center for Theoretical Physics of the Polish Academy of Sciences, Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences, and the National Centre for Nuclear Research, has been awarded a grant of 1.86 million złotys by the Ministry of Science and Higher Education (MNiSW) for this project (grant 2026/WK/06).
In each observation of the southern sky on the VISTA telescope in Chile, run by the European Southern Observatory, 4MOST will simultaneously gather light using optical fibres from 2436 astronomical objects seen by VISTA's 4-metre mirror, and split this light into a spectrum of photons of different energies. These spectra give key astronomical information about the observed celestial objects. Especially for the NCU 4MOST astronomers, led by Prof. Boud Roukema, the primary interest is cosmological. The systematic shift in energies of the photons of distant galaxies that we call "redshift" mainly gives information about how far away the galaxies are, helping to build up a map of a big fraction of the observable Universe. The statistical details of where galaxies are positioned in the new maps will give us new information about some of the mysteries of our current cosmological model, the Lambda cold-dark-matter (LCDM) model.
The current model interprets the older maps that we already have using Einstein's theory of relativity, showing that the simplest interpretation is that about seventy percent of the mass–energy density of the Universe is an unknown phenomenon that we call dark
energy, and another twenty-five percent is another unknown phenomenon that we call dark matter. Yet even the LCDM model is currently having difficulty in properly matching the observations of some of the major extragalactic surveys of the sky that astronomers have recently made. As 4MOST will make the largest extragalactic spectroscopic survey in the southern hemisphere, Polish astronomers will be at the forefront of testing the standard cosmological model and of better measuring galaxy evolution.