GS Paper - 3 (Science and Technology)

While a lot about the Milky way galaxy remains unknown to us, recently astronomers have been able to discover a break in one of its arms. Astronomers have found ‘a contingent of young stars and star-forming gas clouds’ sticking out of the Sagittarius Arm of the galaxy, according to a new study published in the Astronomy & Astrophysics journal.


  1. The authors of the study used NASA’s Spitzer Space Telescope before its retirement in January 2020 to study the nearby portion of the Sagittarius Arm.
  2. In their observation, they found some newborn stars nestled in the gas and dust clouds (called nebulae).
  3. The structure discovered in the Milky Way galaxy is stretching over some 3,000 light-years and looks like it is protruding out of the Sagittarius Arm of the galaxy.
  4. It is the first such discovery in the Milky Way galaxy that is seen to have a dramatically different orientation from the other arms.
  5. The circle in the middle has a pitch angle of zero degrees. Gradually as the spiral becomes more open and bigger, the pitch angle of the arms also increases.
  6. Most models of the Milky Way suggest that the Sagittarius Arm forms a spiral that has a pitch angle of about 12 degrees, but the structure we examined really stands out at an angle of nearly 60 degrees.