Astronomers have reconstructed the global chemical composition of our galaxy to understand how it compares to other galaxies in the Universe . It turns out that it is not unique , but it is certainly unusual . This is something that alien astronomer would be able to pick up , and that we can use to understand the peculiar account of the assembly of our galaxy .
atomic number 1 and helium have been in the universe since a few minutes after theBig Bang , but all the other ingredient ( which stargazer call “ the metallic element ” ) are created in stars and stellar processes . A galaxy ’s metallicity says a lot about it . And this new enquiry provides the best looking at yet at the Milky Way ’s metallicity .
“ Finding manner to equate our home galaxy with more distant galaxies is what we need if we require to know whether the milklike Way is special or not . This has been an open question since uranologist realized a hundred years ago that the whitish Way is not the only galaxy in the creation , ” extend generator Jianhui Lian , from the Max Planck Institute for Astronomy and Yunnan University , enounce in astatement .
The metallicity increases from the centre of theMilky Wayto about 23,000 light - years out , plateauing for a number to level of metallicity standardised to that of the Sun . The Sun is 26,000 light - years from the centre . But then , the metallicity drop again , die down to about one - third of solar at a length of 50,000 light - year at the edge of our galaxy .
Compared to surveys of other beetleweed such as MaNGA or simulations of galaxies such as TNG50 , our coltsfoot ’s high metallicity donut is peculiar . Only one per centum of the surveyed galaxies and only 11 percent of the simulated I are quite like our own . The discrepancy between the two turn is due to incertitude in the survey and the limitation of make realistic pretending of the cosmos .
The rarity of our galaxy at its magnetic core could be due to natural process from thesupermassive disgraceful hole , which might have pushed more alloy - racy gas outwards , break the formation of younger , more alloy - fat stars . And at its edge , a hit with a small galaxy lack in metal could have brought more pristine textile , create a large universe of alloy - piteous stars .
“ The findings are very exciting ! This is the first time that we can meaningfully compare the elaborated chemical content of our galax with the measure of many other galaxies , ” co - generator Maria Bergemann , also from the Max Planck Institute for Astronomy , explain .
“ The results are authoritative for the next generation of comprehensive study of galaxy formation . Those studies will use datum from upcoming big - scale observational programs targeting the Milky Way or targeting distant extragalactic nebula . Our research shows how to sensibly aggregate the two kinds of information set . ”
The study is published inNature Astronomy .
