Secrets of the Milky Way revealed by huge space probe map

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Paris (AFP) – The Gaia space probe unveiled its latest findings on Monday in its quest to map the Milky Way in unprecedented detail, probing nearly two million stars and revealing mysterious “starquakes” sweeping across fiery giants like vast tsunamis.

The mission’s third dataset, which will be released to eagerly awaiting astronomers around the world at 1000 GMT, “revolutionizes our understanding of the galaxy”, the European Space Agency (ESA) said.

“It’s the Swiss army knife of astrophysics – there isn’t a single astronomer who doesn’t use its data, directly or indirectly,” said Gaia team member Francois Mignard.

Some of the map’s new information is close to home, such as a catalog of more than 156,000 asteroids in our solar system “whose orbits the instrument calculated with incomparable precision,” Mignard said.

But Gaia also sees beyond the Milky Way, spotting 2.9 million other galaxies as well as 1.9 million quasars – the incredibly bright cores of galaxies powered by supermassive black holes.

The Gaia spacecraft is nestled in a strategically positioned orbit 1.5 million kilometers (937,000 miles) from Earth, where it has been watching the skies since its launch by ESA in 2013.

– ‘Beautiful crucible of stars’ –

“Gaia scans the sky and picks up everything it sees,” said astronomer Misha Haywood of the Paris Observatory.

But it still can only detect about 1% of the stars in the Milky Way, which is about 100,000 light-years across.

The probe is equipped with two telescopes as well as a billion-pixel camera, which captures images sharp enough to measure the diameter of a human hair at a distance of 1,000 kilometers (620 miles).

It also has a range of other instruments that allow it not only to map stars, but also to measure their motions, chemical compositions and ages.

“It provides a global observation of the positions of everything that moves in the sky, for the first time,” Haywood said, adding that before Gaia “we had a really restricted view of the galaxy.”

It also reveals the huge range of differences between stars.

“Our galaxy is a beautiful melting pot of stars,” said Gaia member Alejandra Recio-Blanco.

“This diversity is extremely important, because it tells us the story of how our galaxy formed,” he said.

“It also shows clearly that our Sun, and we, all belong to an ever-changing system, formed through the coming together of stars and gases of different origins.”

Surprise Starquakes

The observation of “starquakes”, massive vibrations that alter the shape of distant stars, was “one of the most startling findings to come out of the new data”, the ESA said.

Gaia was not designed to observe starquakes, but has still detected the strange phenomenon on thousands of stars, including some that shouldn’t have any – at least according to our current understanding of starquakes. ‘universe.

“Gaia opens up a gold mine for the ‘asteroseismology’ of massive stars,” said Gaia Fellow Conny Aerts.

About 50 scientific papers have been published alongside the new data, and many more are expected in the coming years. Observations from Gaia have powered thousands of studies since its first dataset was released in 2016.

The second set of data in 2018 allowed astronomers to show that the Milky Way merged with another galaxy in a violent collision around 10 billion years ago.

The torrent of raw data was combed through by a team of 450 European scientists and software engineers using six supercomputers as well as “human-driven algorithms” as part of the Data Processing and Analytics Consortium, a said Mignard.

“Without this processing group, there is no mission,” he added, as Gaia produces 700 million star positions and 150 million photometric measurements every day.

It took the team five years to provide the latest data, which was observed from 2014 to 2017.

“We can’t wait for the astronomical community to dive into our new data to learn even more about our galaxy and its surroundings than we could have ever imagined,” said Timo Prusti, ESA’s Gaia project scientist.

The final dataset will be released in 2030, after Gaia completes its sky surveying mission in 2025.

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