During the 1950s astronomers used data from radio telescopes and determined that our spiral galaxy has four arms . In 2008 , figure of speech from NASA ’s Spitzer Space Telescope demo that the Milky Way only had two arms . However , the conclusion of a 12 - year - foresightful study has shown that there are in fact four arms on our extragalactic nebula . The results were write in theMonthly Notices of the Royal Astronomical Society .
During the 12 year study , a team of researchers studied around 1650 monolithic stars with radio telescopes and reconfirm that based on the distribution and luminosity , there arefour arms on the spiralof our galax . This contradicts findings from theSpitzer Space Telescopethat showed that there are 110 million stars , and those two were confined to two spiral weapon system , not four .
So how was Spitzer so untimely ? Well , the range of a function were n’t exactly untimely , but they were n’t able to see the intact picture . Spitzer works on infrared , and it is capable to capture information about stars much like our sunlight , which are relatively down mass and are nerveless . Because this recent datum focused on raging , massive stars , Spitzer was unreasoning to them and was ineffective to factor them in .
Massive stars are somewhat rarified and can experience for about 10 million years , which is only a blink of an middle on the cosmic time scale . They are born , resilient , and die within the same weapon . Stars that are more like our sunlight have more metre to spin about in the galaxy and spread out . gravitative puff is only strong enough to garner stars in two of the arms , which Spitzer was capable to detect . However , the other two weaponry have enough compact petrol to allow for massive genius to organize . The better astronomers empathise the structure of our galaxy , the easier it becomes to see how and why monolithic stars form .
Because we are not able-bodied to at once observe the intact construction of the Milky Way ( on business relationship of being inside it and all ) , we must bank on observations from tool like radio receiver telescopes and the Spitzer Space Telescope . unluckily , there are times like these when two data point set up engagement . This is why it is crucial for astronomer to factor in all of the evidence before making claims about absolutes , and also to keep revisiting ideas when new grounds is introduced .
