- NASA's Roman Telescope will measure cosmic voids with unprecedented accuracy to study universe expansion
- Cosmic voids are vast empty spaces governed by dark energy that accelerate the universe's expansion
- The Roman High-Latitude Wide-Area Survey will detect thousands of voids using galaxy positions and redshifts
Our universe is vast, filled with galaxies stretching in every direction as far as telescopes can see. Some scientists estimate there could be as many as two trillion galaxies in the observable universe. While these galaxies may look randomly scattered, they are actually arranged along the surfaces of enormous cosmic "bubbles," some spanning hundreds of millions of light-years. The empty spaces inside these bubbles, where very few galaxies exist, are called cosmic voids. NASA's Nancy Grace Roman Space Telescope will help measure these voids with unprecedented accuracy, offering new insights into the universe's expansion, reported NASA.
Giovanni Varza of the FlatIron Institute and New York University, lead author of a study published in the Astrophysical Journal, explained that the Roman telescope's ability to observe vast areas of the sky and detect distant, faint galaxies will revolutionise the study of cosmic voids (empty space regions).
These voids, which contain very little matter, are governed by dark energy, which helps the universe expand rapidly. Alice Pisani of CNRS and Princeton University said that studying voids will help scientists understand the nature of dark energy.
The universe is made up of three main components - normal matter, dark matter, and dark energy.
The gravity of normal and dark matter slows the expansion of the universe, while dark energy accelerates it.
Scientists study their effects on observable phenomena such as galaxy distribution. Pisani compared this process to making a cake and said that by using the right cosmic "ingredients" and stacking voids and comparing their shapes, we can determine whether our assumptions about the universe are correct.
To study voids, researchers will use the Roman High-Latitude Wide-Area Survey, one of the three main surveys of the Roman Telescope.
This survey will look at regions far from the plane of the Galaxy and is estimated to detect thousands of voids, some only 20 million light-years wide. The 3D shapes of the voids will be determined using the positions of galaxies and their redshifts derived from spectroscopic data. The large number of voids allows scientists to use statistical methods to see how matter and dark energy influence their shapes.
Studying voids requires observing vast regions of space, as the voids themselves can span hundreds of millions of light-years. The Roman Telescope will cover approximately 2,400 square degrees of sky, equivalent to about 12,000 full moons. Its ability to detect faint and distant galaxies is superior to other missions, such as ESA's ULIDS. Julia Degni of Rome Terrace University and INFN said that Roman's observations will allow scientists to study the sparse galaxies present in voids, helping to understand cosmological parameters such as dark energy.
The Roman telescope promises to provide a clearer picture of the large-scale structure of the universe and the forces shaping it, bringing scientists closer to understanding the cosmic puzzles of dark matter, dark energy, and the distribution of galaxies.
