European space telescope releases unprecedented details about our galaxy

The European Space Agency (ESA) has released a trove of data on almost two billion stars in the Milky Way, collected by its Gaia mission in an effort to create the most accurate and complete map of our galaxy.

Astronomers hope to use the data to understand better how stars are born and die, and how the Milky Way evolved over billions of years.

The new data includes new information such as the age, mass, temperature and chemical composition of stars.

"This is an incredible gold mine for astronomy," said Antonella Vallenari, who helped lead a consortium of 450 scientists and engineers that spent years turning the measurements collected by the probe into usable data.

Gaia's mission is to create the most detailed and complete multi-dimensional map of our galaxy, which will allow astronomers to investigate the Milky Way's structure and evolution as well as help them to better understand the life cycle of stars.

Gaia was also able to detect more than 100,000 so-called starquakes, which ESA likened to large tsunamis that ripple across stars. These allow scientists to deduce the density, interior rotation and temperature inside stars, astrophysicist Conny Aerts said.

The new release is also the largest catalogue of binary stars (stars that orbit a shared centre of mass), thousands of solar system objects like asteroids, moons and planets, as well as millions of galaxies.

It also found that some stars in our galaxy are made of ancient material from elements left over from the creation of our universe, while others are made from matter from earlier generations of stars: the stars closer to the centre and plane of our galaxy are richer in heavy metals than stars farther out. 

As well, Gaia classified stars that came from outside our galaxy.

"Our galaxy is a beautiful melting pot of stars," Alejandra Recio-Blanco of the Observatoire de la Côte d'Azur in France, who is a member of the Gaia collaboration, said in the release.

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Although it has only collected information on about one per cent of the Milky Way's stars, the mission is already providing the basis for around 1,600 scientific publications a year.

Project scientist Timo Prusti said the sheer number of stars observed makes it more likely that scientists will make very rare discoveries.

"You have to observe a lot of objects in order to get the needle in the haystack," he said.