The Milky Way and Andromeda are on a hit row and they will smash together in the distant future . Now the European Space Agency ’s scope Gaia has refined the measurement of Andromeda ’s speed and the merger is expected to begin in 4.5 billion years , about 600 million class subsequently than previously expect .
Gaia is take elaborate observations of billions of star in the Milky Way to valuate their position and swiftness , but its instruments are so sophisticated that it can track lead even in other galaxies . Researchers have used the data from the mission’ssecond data releaseto analyse the movement of Andromeda and another near - by extragalactic nebula , Triangulum . The finding are account in theAstrophysical Journal .
Triangulum and Andromeda , also known as M31 and M33 , are two of the main galax in the Local Group of galaxy . Together with the Milky Way , they make up most of the Local Group ’s mass . Armed with the data from Gaia , researchers were capable to estimate that the first interaction between our galaxy and Andromeda will be more of a glance hit than a psyche - on collision .
By track massive bright stars , the uranologist were also able-bodied to work out the whirl of these objects , the rate at which they rotate on their own axis . This is a measurement that researchers have been working on complicate for a century .
“ For the first time , we ’ve assess how M31 and M33 go around on the sky . uranologist used to see galaxy as flock worlds that could n’t possibly be separate ‘ islands ’ , but we now have a go at it otherwise , " lead writer Roeland van der Marel , from the Space Telescope Science Institute , said in astatement . “ It has film 100 years and Gaia to finally measure the rightful , flyspeck , rotation rate of our nearest tumid galactic neighbor , M31 . This will help us to understand more about the nature of galaxies . ”
The observation also designate how Triangulum is moving around Andromeda . In the past it has not been clear if M33 had already perform a flyby of M31 , or it was just start to fall in . Now , astronomers have worked out that Triangulum ’s velocity can only be explain if this is the first meter it ’s amount close to Andromeda .
“ This finding is important to our agreement of how galaxies develop and interact , ” added Timo Prusti , ESA Gaia Project Scientist . “ We see unusual features in both M31 and M33 , such as warped streams and tails of gas and star . If the extragalactic nebula have n’t come together before , these ca n’t have been create by the forces felt during a amalgamation . Perhaps they formed via interactions with other galaxy , or by gun dynamics within the beetleweed themselves . ”
