Space: Around 40,000,000,000,000,000,000 black holes make up 1% of the observable universe - Daily Mail

The observable universe contains 40,000,000,000,000,000,000 stellar-mass black holes — that's 40 quintillion, or 40 billion billions, a study has estimated.

The findings, the team said, pave the way to a better understanding of how stellar- and intermediate-mass black holes might evolve into supermassive black holes.

The observable universe contains 40,000,000,000,000,000,000 stellar-mass black holes — that's 40 quintillion, or 40 billion billions, a study has estimated.

In their study, astrophysicist Alex Sicilia and colleagues calculated the number of stellar-mass black holes not in the whole universe — but the 'observable' portion.

To calculate their estimate of the number of black holes in the observable universe, the team combined models of how single and binary star pairs evolve — and thus how many turn into black holes — with data on other relevant galactic properties.

Alongside estimating the total number of stellar-mass black holes in the observable universe, the researchers also explored various routes by which black holes of different masses can form.

The team found that the largest stellar-mass black holes typically form from the collision of smaller black holes within stellar clusters — a notion that matches well the observational gravitational wave data on black hole collisions collected to date.

'Our work provides a robust theory for the generation of light [stellar-mass] seeds for (super)massive black holes at high redshift,' said paper author and astrophysicist  Lumen Boco, also of SISSA.

Many of these black hole seeds then merge to form much larger supermassive black holes, which are found at the centre of every known massive galaxy