An international team of Japanese astronomers said in a new issue of the American Journal of Astrophysics that they may have discovered the traces of supernova explosions left by the first generation of stars in the early days of the universe in the final stages of their "life".

This will be an important clue to studying the "infant" universe.

The first generation of stars consisted of lighter elements such as hydrogen and helium, which formed during the universe's earliest moments. When these stars exploded as supernovae, they released heavier elements into space, providing the essential "raw materials" for the formation of the second generation of stars. However, because the first stars emerged so early and had relatively short lifespans, current observational methods have yet to obtain direct evidence of their existence.

In this study, the researchers used quasars for observational analysis. Because there is a huge black hole at the center of the quasar when the black hole devours the surrounding matter, it emits energy, causing the quasar to be very bright, and the surrounding gas is also easy to observe.

The research team observed and analyzed the gas near a quasar about 13.1 billion years ago and found that the content of iron in it is more than 10 times that of magnesium, which is significantly abnormal compared with the ratio of iron and magnesium in the sun. They argue that this unusual ratio of element abundance cannot be explained by a typical supernova explosion.

After relevant calculations, the researchers deduced that the gas was the traces of a "paired unstable supernova" explosion in a star about 300 times the mass of the sun. After analyzing the age of the quasar, they believe that the star that exploded in this huge supernova is the first generation of stars after the birth of the universe.

The universe is thought to have originated from a massive cosmic expansion about 13.8 billion years ago. This time, the researchers discovered traces left by the first generation of stars just 700 million years after the universe began, providing valuable clues to understanding these early stars and exploring the mysteries of the universe in its infancy.