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Astronomers have discovered evidence of a “fossil galaxy” buried in the depths of the Milky Way, which arrived 10 billion years ago after a collision.
Scientists have called the galaxy “Heracles”, and it is believed to be a holdover from the early universe.
They believe that ancient galactic remains make up about a third of the Milky Way’s spherical “halo” – a region made up of star clusters, gas and dust.
Danny Horta-Darrington / LJMU / Nasa / JPL-Caltech / SDSS / PA Wire
Typically, fossil galaxies are found on the edges of the Milky Way.
Danny Horta-Darrington / LJMU / Nasa / JPL-Caltech / SDSS / PA Wire
However, the current galaxy was found deep inside, indicating that it was a galaxy that first appeared shortly after the universe was formed.
The team used data from the Apogee Galactic Evolution Experiment project at the Apache Point Observatory.
It’s really small in the cosmic context – just 100 million stars – but it’s about half the mass of the entire Milky Way halo. In a fossil like this, we must have looked at the detailed chemical makeup and motions of tens of thousands of stars. This is especially difficult for the stars in the center of the Milky Way, as they are hidden from view due to clouds of interstellar dust. Deeper than ever in the heart of the Milky Way. “
To separate the stars that originally belong to “Heracles”, the team analyzed the chemical makeup of the stars.
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Danny Horta, a graduate student at John Moores University in Liverpool, said: “Of the tens of thousands of stars we looked at, a few hundred had remarkably different structures and chemical velocities. These stars are so different that they are they can only come from a galaxy. ” By studying it in detail, we can trace the exact location and history of this fossil galaxy. “
The team believes the Heracles merger “should be a major event in the history of our galaxy,” according to a study published in The Monthly Notices Of The Royal Astronomical Society.
This would make the Milky Way weird because “most similar massive spiral galaxies have quieter early lives.”
“As a cosmic home, the Milky Way is really special to us, but this ancient galaxy buried within makes it more special,” Schiavon said.
However, the Milky Way has not completed its mergers, as “Andromeda”, the neighboring galaxy closer and larger than the Milky Way, is heading towards us.
Andromeda approaches the Milky Way by about 5 million km per year, and within 2-4 billion years, it could consume our home galaxy.
However, humanity will not have to worry about this as our sun will have destroyed the solar system by this point.
Source: Express
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