The James Webb Space Telescope has observed five objects that may represent the earliest star clusters present during the Cosmic Dawn.
According to Live Science, a team of scientists successfully used the James Webb to observe five dense globular clusters within the ancient galaxy known as “Cosmic Gems.”
Cosmic Gems is seen as an arc of light, often referred to as the “Cosmic Gems Arc”, existing just 460 million years after the Big Bang event.
Thus, the five newly observed primordial globular clusters may represent some of the first objects born from the “primordial chaos” of the universe, which is now 13.8 billion years old.
Globular clusters within the Cosmic Gems galaxy, seen thanks to the magnification effect of a foreground lensing galaxy – (Image: NASA/ESA/CSA).
According to Dr. Angela Adamo from Stockholm University in Sweden, the lead author of the publication in the scientific journal Nature, this observation was a fortunate outcome thanks to gravitational lensing.
Light takes a corresponding time to travel to Earth based on distance, so what we are seeing of a primordial object is essentially an image of it from the past, in its past location, before it was pushed too far away due to the expansion of the universe.
Nevertheless, observing an object at a distance of more than 13 billion light-years remains a challenge even for James Webb.
However, a massive galaxy named SPT-CL J0615-5746 fortuitously lies directly between our galaxy and Cosmic Gems, acting as a giant magnifying glass that enhances the view of the ancient galaxy, boosting James Webb’s capabilities.
Objects like SPT-CL J0615-5746 are referred to in astronomy as gravitational lenses, as the galaxy’s immense gravitational force bends spacetime, distorting the light passing through it, thus creating a magnification effect.
This effect has caused us to see Cosmic Gems not as a normal galaxy, but rather with its light distorted, transforming the galaxy’s image into an arc. Importantly, it has become sufficiently large for us to clearly see the five globular clusters within.
Globular clusters are dense star groups bound together by strong gravitational forces, helping stars extend their lifespans. Therefore, globular clusters are considered the “fossils” of the universe that scientists actively seek.
The star clusters within Cosmic Gems are extremely dense, denser by about three levels compared to star formation regions observed closer to Earth.
These globular clusters are among the oldest ever observed, although it is not yet certain that they are the first globular clusters that formed in the universe.
Nonetheless, they provide astonishing evidence that star formation was quite vigorous in galaxies previously thought to be very simple and small during the Cosmic Dawn – the first billion years following the Big Bang.
Clearly, from this primordial era, star formation in clusters was already taking place.
“To form massive primordial globular clusters, the host galaxy must have the ability to generate and retain sufficient gas mass. Therefore, everything depends on the growth rate of primordial galaxies,” Dr. Adamo noted.
This presents new evidence supporting the increasingly accepted hypothesis in recent years since humanity has had the James Webb: The universe’s first few billion years developed very vigorously, rapidly, and complexly, even more so than the pace seen today.
