The Gaia mission, whose space observatory developed a detailed three-dimensional map of the Milky Way, unveils a new version this Monday with information on the location, trajectories and characteristics of nearly 2,000 million objects.
The community of astronomers will be able to immerse themselves in the third catalog of the data collected by the instrument. Added to this are fifty scientific articles on a host of celestial objects.
The information ranges from more than 150,000 asteroids in the Solar System, “whose orbits have been calculated with incomparable precision”, through data on 1,500 million stars in the Milky Way, to those relating to other galaxies and quasars, François told AFP Mignard, one of the people in charge of this project from the European Space Agency (ESA).
The Gaia observatory has been in operation since 2013, located at the Lagrange 2 point (L2), where, due to the gravitational influences of the different bodies, it remains in orbital equilibrium 1.5 million kilometers from Earth.
“Gaia scans the sky, and collects everything it sees” sums up astronomer Misha Haywood, at the Paris-PSL Observatory. He detects and observes a very small part (barely 1%) of the stars in the Milky Way, whose diameter is estimated at 100,000 light-years.
But Gaia is not limited to establishing a simple map. Her two telescopes are associated with a photographic sensor of 1,000 million pixels, when that of a commercial photo device has only a few million. Three astrometry, photometry and spectrometry instruments will interpret the recovered photons.
“This allows for the first time a global observation of the positions of what is moving in the sky” explains Haywood. Before Gaia, “we had a really restricted view of the galaxy.”
With Gaia, astronomers not only have access to the positions and movements of a large number of stars, but also measurements of their physical characteristics and, above all, their age.
So much information “illuminates us about its past evolution, and therefore about the evolution of the galaxy” explains astronomer Paola di Matteo, a colleague of Misha Haywood at the Paris-PSL Observatory.
For his part, the Finnish astronomer Timo Prusti explained that “before this mission it was as if we were inside a forest, we only saw trees, now we are in the sky and we can see everything from a bird’s eye view.”
As for the composition of the stars -something that can provide information about their place of birth and their subsequent journey, and therefore about the history of the Milky Way-, the data collected by Gaia allow us to understand what they contain.
Some, for example, have more heavy metals than others, the BBC reported.
“Some stars in our galaxy are composed of primordial material and others, like our Sun, contain enriched matter from previous generations of stars,” explains the ESA statement.
And he adds that the stars closest to the center of our galaxy are richer in metals than those that are further away. On the other hand, Gaia also managed to identify stars that originally came from galaxies other than our own, thanks to the analysis of their chemical composition.
The mission will continue to collect data on stars and other objects inside and outside the solar system and beyond our galaxy until 2025.
The distances on this map are staggering. Each light year is almost 10 billion kilometers. The Earth and the rest of the solar system travel at 720,000 kilometers per hour around the center of the Milky Way, where there is a supermassive black hole, Sagittarius A*.
But even at this speed it will take 230 million years to make a complete revolution. In turn, the Milky Way is a small island of stars that travels through the immensity of a universe where there are another 100,000 million galaxies separated by sidereal distances.
The new map confirms that the solar system is within the so-called “local bubble”, an area fairly devoid of stars and with a low concentration of gas and interstellar dust, which allows a fairly clear view of the rest of the galaxy.