40 Billioп Billion Black Holes Exist iп Օυr Uпiverse

 

According to a recently Published estimate, the observable universe includes about 40 billion billion (4x1019, or 40,000,000,000,000,000,000) black holes.  if you find that number difficult to comprehend, but another way to put it is that around 1% of the universe's "ordinary" matter contained in the form of black holes.

This study was carried out by PhD candidate Alex Sicilia, and it was subsequently published in the Astrophysical Journal (Scuola Internazionale Superiore di Studi Avanzati, Italy).

Of course, Sicilia didn't actually count the black holes. Instead, the study drew its support from the discovery that the majority of black holes are created when stars with masses greater than 20 times that of the Sun die. The result is an entity that is 5-160 times as massive as the Sun and so dense that even light is pulled into its powerful gravitational field.

Using estimates of the number of stars with the necessary mass that have been created from the Big Bang up to the present, Sicilia was able to determine the number of black holes left behind.

The research indicates that "the “the result was obtained thanks to SISSA researcher Dr Mario Spera who developed an original approach which combines the state-of-the-art stellar and binary evolution code SEVN”. 

This took into account the most recent estimates for the properties of galaxies, "particularly the pace of star formation, the amount of stellar mass, and the metallicity of the interstellar medium (which are all critical criteria to predict the number and masses of stellar black holes)".

The work not only counts the number of black holes but also assesses the distribution of their masses. As a result, the researchers were able to estimate that stellar-sized black holes are home to 1% of the universe's baryonic matter. Baryonic matter, often known as "ordinary" matter, is made up of the well-known protons and neutrons, as opposed to the mysterious dark matter and even more mysterious dark energy.

Despite being millions of times more massive than one another, the supermassive black holes in the centres of many galaxies are a rounding error in terms of the overall number of black holes.

Although black holes were hypothesised in the 18th century, they weren't really discovered until 1990, when they were supposed to be proof that they existed.