Huge graveyard of stars surrounds our galaxy, scientists say

Welcome to the “galactic underworld”.

Stellar Necropolis

Even stars eventually die. And even the stars need a final resting place. Researchers from the University of Sydney have been scrambling to uncover such a location, searching for the celestial remnants of ancient suns that have collapsed into black holes or neutron stars.

What they found – and successfully mapped for the first time – was a stellar graveyard far exceeding the height of our own galaxy. Publication of their accompaniments study in Royal Astronomical Society Monthly Notice, the researchers rightly call their discovery a “galactic underworld.”

“The ‘height’ of the galactic underworld is more than three times greater in the Milky Way itself,” said lead author David Sweeney, a PhD student at the Institute of Astronomy in Sydney, in a press release. “And an incredible 30% of the objects were completely ejected from the galaxy.”

starmy of darkness

Black holes and neutron stars form as a result of a supernova, a cataclysmic explosion that occurs when massive stars collapse in on themselves at the end of their lifespan. The powerful explosion propels these stellar remnants into dark regions of space, where they prove elusive to astronomers.

But by meticulously simulating the lifespans of quondam stars, the researchers were able to predict where their corpses ended up.

“The hardest problem I had to solve in researching their true cast,” Sweeney said, “was accounting for the ‘kicks’ they receive in the violent moments of their creation. “

“Supernova explosions are asymmetrical and the remnants are ejected at high speeds – up to millions of kilometers per hour – and, even worse, it happens in an unknown and random direction for each object.”


Mapping this underworld is a fascinating undertaking, but what researchers have found particularly remarkable is its composition.

“These compact remnants of dead stars show a fundamentally different distribution and structure from the visible galaxy,” Sweeney said.

Sanjib Sharma, a researcher at the University of Sydney who helped map the cemetery, was also impressed.

“I expected the Galactic Underworld to be subtly different, but similar in broad outline,” Sharma said in the statement. “I didn’t expect such a drastic change in shape.”

Learn more about stars: A supercomputer spits out a stunning image of an exploded star