Map of Milky Way’s Graveyard of Dead Stars

Syllabus: General Studies Paper 3

Researchers have created a chart of the corpses of massive stars that have since collapsed into black holes and neutron stars. 

• The study reveals that this “galactic graveyard” stretches three times the height of the Milky Way and that close to one-third of the objects have been flung out from the galaxy.
• These compact remnants of dead stars show a fundamentally different distribution and structure to the visible galaxy.
• The ‘height’ of the galactic underworld is over three times larger in the Milky Way itself. And an amazing 30 per cent of objects have been completely ejected from the galaxy.

Formation of Black Hole

• Black holes and neutron stars are formed when stars which are more than eight times larger than our Sun exhaust their fuel supply and suddenly collapse. 
• When this happens, it triggers a reaction that blows apart the outer portion of the star in a supernova explosion. 
• Meanwhile, the core keeps compressing itself until it becomes either a neutron star or a black hole, depending on its starting mass.

Neutron Stars 

• Neutron stars have cores so dense that electrons and protons combine at the subatomic level to form neutrons. 
• This squeezes its total mass into a sphere that is “smaller than a city.”
• If the starting mass of the star is more than 25 times that of our Sun, this collapse will continue until the core gets so dense that even light cannot escape, creating a black hole. 
• Both kinds of stellar remnants warp space, time and matter around them due to their density.