The Milky Way , like many helical galax , is made of a thick central swelling and a large lean disk of stars . Recently we have learned that this thin disk isnot flat , but warped . The latest observations indicate that the warp moves around the beetleweed every 440 million years , a minute like a bowl undulation . The unexampled findings were deliver at the 237th Meeting of the American Astronomical Society this week .
The warp is believe to have been do by the hit between the Milky Way and a smaller galaxy . mavin further away than the Sun go around the milklike Way every 225 - 250 million old age and also move up and down the aeroplane of the thin disk every 440 million years .
" Our common photo of a whorled galaxy is as a flat disk , lean than a pancake , peacefully rotating around its center , " say Xinlun Cheng of the University of Virginia , the jumper cable author of the study , in astatement . " But the realness is more complicated . Imagine that you are in the stands at a football game , and the crowd starts doing the wave . All you do is stand up up and seat down , but the effect is that the wave goes all the elbow room around the bowl . It ’s the same with the Galactic Warp – stars only move up and down , but the moving ridge travel all the way around the Galaxy . "
The pernicious warp of the Milky Way becomes clear by reflecting the galaxy on itself in this gif based on 2MASS imaging . Image Credit : 2MASS , Adrian Price - WhelanCC BY 4.0
The study combine data point on C of thousands of stars from the Apache Point Observatory Galactic Evolution Experiment ( APOGEE ) , part of the Sloan Digital Sky Survey ( SDSS ) . The squad uses the spectrum of luminosity from each champion as a way to recognize where that star is from . When this was combined with data from the European Space Agency’sGaia observatory , the squad had a much clear idea of how the warp moves through the galaxy .
" The APOGEE spectrum supply selective information about the chemical makeup and motions of single stars , " add Dr Borja Anguiano of the University of Virginia . " That countenance us to separate them into unlike groups , which in play allows us to abide by the warp separately within each group of star . "
This study has estimated the focal ratio and the extent of the waving with more preciseness than ever before . For decennary , it ’s been known that more than one-half of all spiral galaxies ( possibly up to seven in 10 ) are heave . Studying the warp of the Milky Way is far from easy given that we are in it , but it is crucial to understand ours and other galaxies .
