The space telescope James Webb continues to yield surprising discoveries. This time, it has identified five ancient cosmic gems, never seen before, in a primordial galaxy less than 500 million years after the Big Bang. The discovery, fundamental to understanding the evolution of galaxies in the early universe, was published in the journal Nature by an international team led by the Italian astronomer Angela Adamo of the University of Stockholm, with the collaboration of Eros Vanzella and Matteo Messa of the National Institute of Astrophysics in Bologna.
A Journey into the Early Universe
The young galaxies of the early universe are a veritable goldmine of information, as they have gone through phases of intense star formation. During these phases, enormous amounts of ionizing radiation were generated, making the universe more transparent, a phenomenon known as era of reionization. Observing these distant galaxies is a challengebut the universe itself offers precious help: the gravitational lenses. These extremely dense distributions of matter curve spacetime and bend light, amplifying that coming from distant galaxies.
Cosmic Gems: An Unprecedented Discovery
Thanks to this effect, the very young galaxy called Cosmic Gems Arcdating back to just 460 million years after the Big Bang. The galaxy was first observed by the Hubble Space Telescope in 2018, but it is thanks to the James Webb that we can now admire its details. For the first time, the internal properties of a galaxy so distant have been observed.
The researchers identified five star clusters with dimensions of about 3-4 light-years, a thousand times denser respect typical young star clusters in the local Universe. “The surprise was incredible when we opened the Webb images for the first time,” comments Angela Adamo.
“We saw a small chain of bright points: these cosmic gems are star clusters! Without Webb, we would not have known we were seeing star clusters in such a young galaxy.”
Implications of the discovery
The presence of such dense and massive star clusters is significant for two reasons. First, they could be the precursors of the globular clusters that populate today’s galaxies. Second, such young star clusters can alter the interstellar medium of their host galaxy and, with their massive stars, play a key role in the process of reionization of the universe.
Eros Vanzella adds: “We are finally revealing the origins of the first galaxies thanks to the quality and power of the James Webb telescope and, with the help of gravitational lensing, we are observing unprecedented details. The universe of that time was not like today’s and this now appears to us as a fact”.
What do you think of these discoveries? What other surprises might the James Webb telescope have in store for us?
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