- The finding has a huge impact on what we think we know about the universe.
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| Image released by NASA of the center of the Milky Way. / NASA |
An analysis of light from 140,000 galaxies has revealed that their stars are heavier than previously theorized, which may change the understanding of a wide range of astronomical phenomena. This is the conclusion of a study published in The Astrophysical Journal by a team of researchers from the Niels Bohr Institute at the University of Copenhagen.
Since 1955, it has been assumed that the composition of the stars in the other galaxies of the universe is similar to that of the hundreds of billions of stars within our own: a mix of massive, medium-mass, and low-mass stars.
But with the help of observations of 140,000 galaxies across the universe and a wide range of advanced models, the team has tested whether the same apparent star distribution in the Milky Way applies elsewhere.
The answer is no. Stars in distant galaxies are often more massive than those in our "local neighborhood". The finding has a huge impact on what we think we know about the universe.
The tip of the iceberg
The researchers assumed that the size and weight of stars in other galaxies were similar to ours for more than fifty years, for the simple reason that they could not observe them through a telescope, as they could with the stars of our own. galaxy.
Distant galaxies are billions of light-years away. As a result, only light from its most powerful stars reaches Earth. This has been a headache for researchers around the world for years, as they have never been able to clarify precisely how stars were distributed in other galaxies.
An uncertainty that forced them to believe that they were distributed in a very similar way to the stars of our Milky Way. "We have only been able to see the tip of the iceberg and we have known for a long time that expecting other galaxies to look like our own was not a particularly good guess," said study co-author Charles Steinhardt.
Wide range of implications
For Steinhardt, "galaxies form different populations of stars and this study has allowed us to do just that, which may open the door to a deeper understanding of galaxy formation and evolution."
In the study, the researchers analyzed light from 140,000 galaxies using the COSMOS catalog, a large international database of more than a million observations of light from other galaxies. These galaxies are distributed from the closest to the farthest reaches of the universe, from where light has traveled twelve billion years before being observable on Earth.
According to the researchers, the new discovery will have a wide range of implications. For example, it remains unsolved why galaxies die and stop forming new stars. The new result suggests that this could be explained by a simple trend.