“Making the most accurate and complete multidimensional map of the Milky Way”. It never ceases to amaze me that a project the size of Gaia can be summed up like this, in twelve simple words. It is about reconstructing the structure and evolution of the last billions of years of our galaxy; sink our gaze so deep into the universe that celestial mechanics and our discreet role in it remain black on white.
Now the ESA not only updates the catalog, but also gives us an X-ray of a new type of phenomenon: ‘stellar earthquakes’
What is GAI? Gaia is an ESA mission designed to, as I said, map the Milky Way in as much detail as possible. According to the plans of the European space agency, the map will include things such as the position, speed, direction of movement, luminosity, temperature and composition of almost 2,000 million objects in our Galaxy.
The project was announced in 2013 and datasets have been published in 2016 and 2018. It is now published the third wave of data and I think there is no better way to see the complexity of the work than to take into account that the current ones were collected between July 25, 2014 and May 28, 2017. The ESA teams have taken five years to order and understand the morass of data they had in their hands.
Starquakes… Beyond the improvements of a technical nature and a string of new data, the most interesting thing about Gaia’s third publication is starquakes. They are small movements recorded on the surface of a star that change its shape.
The truth is that Gaia had already found stellar oscillations that caused these celestial bodies to increase and decrease in size periodically. What is particular about these oscillations is that they are radial and that, for that very reason, they maintained the spherical shape of the star. New earthquakes (quasi-tsunamis on a large scale) are non-radial; that is, they alter the overall shape of the star and are therefore much more subtle.
…that shouldn’t exist. Gaia has found them in thousands of stars and, let’s be honest, these stars should not register any earthquake (of any kind). At least if we stick to the current theories we have about them. This is why, as Conny Aerts of Ku Leuven in Belgium explained, “starquakes give us a lot of information about stars, especially about their inner workings.” To the point that the asteroseismology of massive stars is going to become one of the topics of the decade.
One more thing. Finally, and as if that were not enough, Gaia has realized that the composition of stars can give us information about their place of birth and their subsequent trajectory. It works, if we pay attention, as if it were a kind of DNA and, in that sense, Gaia (the largest chemical map of the Galaxy) is also a very long history of the diversity, adventures and future of the Milky Way.