You might have take heed that galaxies come in different types , classified based on their shape . There are elliptical galaxies , which are smooth and featureless , search like giant blobs of light . Then there are irregular galaxy , which have often beenpulled into foreign shapesby the force of gravity as theymerged with or come about near byanother galaxy . And then there are the iconic helical galaxies , like our Milky Way , which have long weapon system - like human body accomplish out from their nitty-gritty to form a classifiable structure .
However , not all turbinate galaxies are created adequate , as two recent images from the Hubble Space Telescope show . The image above shows galaxy NGC 3596 , a neat and orderly spiral Galax urceolata . And the persona below shows galaxy Arp 184 ( also known as NGC 1961 ) , which is a character called a peculiar spiral extragalactic nebula .
One of the most obvious remainder between the two images is the way that the Galax urceolata seem from Earth : we are appear at NGC 3596 brass - on , so it appears particularly regular . Galaxy Arp 184 , however , we are catch from an slant , so it seem different . More than that , though , Arp 184 is skewed so that it is n’t absolutely coiling shaped . However , it understandably is n’t a featureless elliptical galaxy either , so it was categorized as a peculiar wandflower in the delightfully namedAtlas of Peculiar Galaxies , compiled by Halton Arp in 1966 .
This NASA/ESA Hubble Space Telescope image features a peculiar spiral galaxy called Arp 184 or NGC 1961.ESA/Hubble & NASA, J. Dalcanton, R. J. Foley (UC Santa Cruz), C. Kilpatrick
The volute arm closest to us in the image of Arp 184 is prominent and broad , but there is no equivalent large arm on the opposite side . The galax is asymmetrical , which is what mark it out as unusual .
Compare that to galaxy NGC 3596 , which has neat arms of exchangeable sizes , which glow garden pink in this image to present area of engaged mavin formation . So why do some galaxies make grow spiral implements of war but not others , and why do these arms fare in so many different material body and sizes ? That ’s something that uranologist are still studying , but it has to do with the denseness of wiz in certain parts of the galaxy .
“ research worker believe that spiral arms represent a pattern of high - density and low - density region rather than a forcible structure , ” Hubble scientistsexplain . “ As stars , gas and junk orbit within a Galax urceolata ’s disk , they pass on in and out of the spiral arms . Much like cars move through a dealings jam , these materials slow down and bunch up as they enter a volute arm , before emerge and continuing their journeying through the galaxy . ”
