Slovenian researchers, together with international experts, have made a groundbreaking discovery about the evolution of the properties of cosmic dust in galaxies that formed soon after the Big Bang, based on data from the James Webb Space Telescope. Their study, published in the scientific journal Nature Astronomy on 6 January, also reveals the key role of early supernovae in cosmic dust's formation.

"The findings provide crucial insights into the life cycle of cosmic dust, its evolution over billions of years, and the key role of early supernovae in its formation," lead author Vladan Markov from the Faculty of Mathematics and Physics at the University of Ljubljana explained.

A fundamental building block of galaxies, space dust consists of tiny particles and plays a key role in star formation, as it allows clouds of molecular gas to form.

It also absorbs and scatters and eventually re-emits the light from stars in galaxies, depending on their wavelength, a process known as attenuation.

Despite its importance, little is known about how much cosmic dust there is in the earliest galaxies, the faculty noted in a press release.

The team of researchers led by Markov analysed data from 173 distant galaxies which formed when the universe, which is 13.7 billion years old, was just 400 million to 3 billion years old.

They found that the dust attenuation curves in early galaxies are generally flatter than those in the local universe.

This suggests that cosmic dust had a less significant effect on the observed light from these distant galaxies.

This flatter shape suggests that the dust in the early universe was dominated by larger grains, probably formed in the remnants of supernova explosions, according to the faculty.

In later epochs, smaller grains became more abundant as they underwent processing in the interstellar medium, leading to steeper attenuation curves and the appearance of the so-called ultraviolet bump, as seen in nearby galaxies, including the Milky Way.