A decade ago, the European Space Agency (ESA) launched the Gaia mission, with the goal of creating a 3-D map of our galaxy.
After observing nearly 1.8 billion stars, and having obtained an almost complete map of the Milky Way, Scientists realized a crucial problem: they did not have a clear view of parts of the sky that were full of stars.
For this reason, those who run the Gaia space observatory decided to better study these super conglomerates of stars called globular clusters.
The study was an analysis in which previously collected data was reviewed. ESA asked for the collaboration of amateur astronomers to help analysts.
These They focused on the Omega Centauri cluster, about 17,090 light years from Earth. The research revealed half a million new stars in that cluster alone. He also found cosmic objects so heavy that they are capable of bending light.
What are globular clusters?
Globular clusters are a dense collection of hundreds of thousands of stars.. They are some of the oldest objects in the universe. Detecting these clusters helped scientists realize that the Sun was not at the center of the spiral galaxy we call the Milky Way.
most of The galaxy’s globular clusters are located near the center of the Milky Way. Using their locations, they discovered that the Sun (and Earth) were in open clusters found in one of the galaxy’s spiral arms: the Sagittarius arm.
Astronomers have been mapping the Milky Way for centuries, but the sheer number of stars it contains can sometimes overwhelm the capacity of telescopes and our ability to read the maps correctly.
Bright stars in clusters often outshine their faint neighbors, and some stars are too close to each other to be defined separately. Gaia has now presented a clearer picture than ever of those groups.
Why did Gaia choose Omega Centauri?
Omega Centauri is the largest known globular cluster in the Milky Way that can be seen from Earth. It appears to be almost as large as a full Moon when viewed from remote, dark areas.
It has a diameter of 150 light years.. It is estimated to be four million times heavier than the Sun, and spans about 10 million stars. Scientists working on Gaia mapped the cluster by observing its core whenever it came into view.
The half a million new stars revealed in Omega Centauri means it is the most populated region explored by Gaia so far. The data can help us understand how the Milky Way’s stars are distributed and why some parts of the universe, like these clusters, have more mass than others.
The universe through the gravitational lens
Light tends to warp when passing through dense objects, such as globular clusters. These heavy clusters have a greater gravitational pull, which is why they bend light due to a phenomenon called gravitational lensing.
Cumulus clouds behave like a giant magnifying glass or lens that can amplify light and emit multiple images of distant sources in the sky.
Gaia has recently found 381 cases where evidence of gravitational lensing was observed. ESA scientists say that means the gravity of the Omega Centauri cluster deflected light coming from distant sources called quasars. Quasars are remote sources of bright light that could be powered by black holes.
Gaia has been able to observe these distant quasars, thanks to its lens, through the Omega Centauri cluster. Study co-author Christine Ducourant of the Astrophysics Laboratory in Bordeaux, France, and a member of the mission team, described Gaia as “a true lens finder.”
The study of a single cluster revealed half a million new faint stars that were not known.
In the next data release in 2025, Gaia will provide information on eight more star-studded regions of the sky.
Scientists hope that will help confirm the age of our galaxy, locate its center, verify how stars change throughout their lives, understand galactic evolution and, ultimately, infer the possible age of the universe itself.
(cp/ers)