The Gaia space probe on Monday unveiled its latest findings in its quest to map the Milky Way in unprecedented detail, surveying nearly two million stars and revealing mysterious “earthquakes” that sweep through the fire giants like vast tsunamis.
The mission’s third dataset, which was released to eagerly awaiting astronomers around the world at 10:00 GMT, “revolutionizes our understanding of the galaxy,” the European Space Agency (ESA) said.
ESA Director-General Josef Aschbacher told a news conference that it was “a fantastic day for astronomy” because the data “will open the floodgates to new science, to new discoveries of our universe, our Milky Way”.
Some of the map’s new insights came close to home, such as a catalog of more than 156,000 asteroids in our Solar System “whose orbits the instrument has calculated with unparalleled accuracy,” François Mignard, a member of the Gaia team, told AFP.
But Gaia also sees beyond the Milky Way, spotting 2.9 million other galaxies as well as 1.9 million quasars — the incredibly bright hearts of galaxies powered by supermassive black holes.
The Gaia spacecraft is nestled in a strategically positioned orbit 937,000 miles from Earth, where it has been watching the skies since it was launched by ESA in 2013.
The observation of starquakes, massive vibrations that alter the shape of distant stars, was “one of the most surprising findings of the new data”, ESA said.
Gaia wasn’t built to observe starquakes, but it still detected the strange phenomenon in thousands of stars, including some that shouldn’t have any — at least according to our current understanding of the universe.
“Starquakes teach us a lot about stars, especially their inner workings. Gaia is opening a gold mine for ‘asterosismology’ of massive stars,” said Conny Aerts, a member of the Gaia team.
Gaia has surveyed more than 1.8 billion stars, but that’s only about one percent of the stars in the Milky Way, which is about 100,000 light-years across.
The spacecraft is equipped with two telescopes and a billion-pixel camera, which captures images sharp enough to measure the diameter of a single human hair 620 miles away.
The new data includes new information such as the age, mass, temperature and chemical composition of stars. This can be used, for example, to determine which stars were born in another galaxy and then migrated to the Milky Way.
The incredibly accurate data “allows us to look more than 10 billion years into the past history of our own Milky Way,” said Anthony Brown, president of the Data Processing and Analysis Consortium, which combed through the massive amount of data.
Gaia’s results are already “far beyond what we expected” at this point, Mignard said.
They show that our galaxy is not moving smoothly through the universe as thought, but rather “turbulent” and “restless,” he said.
“He’s had a lot of accidents in his life and he still has them,” as he interacts with other galaxies, he added. “Maybe it never stays in a steady state.”
“Our galaxy is indeed a living entity, where objects are born, where they die,” said Aerts.
“Surrounding galaxies are continually interacting with our galaxy and sometimes also falling into it.”
About 50 scientific papers were published alongside the new data, with many more expected in the coming years.
Gaia’s observations have fueled thousands of studies since its first dataset was released in 2016.
The second dataset in 2018 allowed astronomers to show that the Milky Way merged with another galaxy in a violent collision about 10 billion years ago.
The team took five years to deliver the most recent data, observed from 2014 to 2017.
The final dataset will be released in 2030, after Gaia finishes its survey of the skies mission in 2025.
Monday’s launch confirmed just two new exoplanets – and 200 other potential candidates – but many more are expected in the future.
“In principle, Gaia, especially when it lasts a full 10 years, should be able to detect tens of thousands of Jupiter-mass exoplanets,” Brown said.
The Gaia data now released also includes information about 800,000 binaries – stars that move together – as well as several new exoplanets, hundreds of thousands of asteroids in the solar system and millions of objects beyond our galaxy.
The Associated Press contributed to this report.
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