The European Space Agency (ESA) launched a mission, called Gaia, in 2013 to reach the second Lagrange point, a privileged observation site 1.5 million kilometers from Earth. From there, he observed 1,800 million stars to map much of the galaxy that houses the Solar System and another 100,000 million stars, many of them also with planets in between. In all this, many revelations are leaving the scientific community ecstatic.
As revealed in the most accurate map of the Milky Way, there are cannibalized galaxies and stellar earthquakes.
What is the Gaia mission and what is it for?
Gaia is an ESA mission designed to map the Milky Way in as much detail as possible. According to the European space agency's plans, the map will include data such as position, speed, direction of movement, luminosity, temperature and composition. of nearly 2 billion objects in our galaxy.
The project was announced in 2013 and the datasets were published in 2016 and 2018. Now the third wave of data is being published and this information is so complex that the most recent "material" to be analyzed was collected between 25 July 2014 and 28 May 2017.
Therefore, it is a dataset that requires an in-depth understanding and time to understand in detail what researchers have at hand.
Starquakes in the Milky Way?
In addition to technical improvements and a series of new data, the most interesting part of the third version of Gaia data are the stellar earthquakes. These are small movements recorded on the surface of a star that change its shape.
In fact, Gaia had already encountered stellar oscillations that caused these celestial bodies to periodically increase and decrease in size. What is special about these oscillations is that they are radial and therefore maintain the spherical shape of the star. The new earthquakes (quasi-tsunamis on a large scale) are not radial, i.e. they change the general shape of the star and are therefore much more subtle.
It should be noted that this new batch of data completes our overview of the massive galactic disk, 170,000 light-years across but only 1,000 light-years thick. The vast majority of the galaxy's stars are clustered on this surface characterized by two large spiral arms. The solar system is close to one of them, Orion.
What is surprising researchers?
Gaia found these earthquakes in thousands of stars. However, given the information available, these stars should not register any earthquakes (of any kind). At least if we stick to the current theories we have about these stars.
That's why, as Conny Aerts from Ku Leuven in Belgium explained, "stellar earthquakes give us a lot of information about the stars, especially about their inner workings." So much so that stellar seismology from massive stars is about to become one of the topics of the decade.
Finally, Gaia realized that the composition of stars can give us information about their birthplace and subsequent trajectory. It works, if you pay attention, as if it were a kind of DNA and, in that sense, Gaia (the biggest chemical map of the Galaxy) is also a very long history of the diversity, the wanderings and the future of the Milky Way.