What is a black hole and what are its types?

Blackholes are fascinating celestial objects that have captivated the interest of astronomers and astronomy enthusiasts for a long time. Regardless of being named ‘Black Holes’, they aren’t holes but rather massive collections of matter crowded into significantly small areas. Their gravitational force is so high that nothing, not even light, can slip away once it goes beyond a line referred to as the event horizon. This boundary defines the point from where nothing can return.

Although there are a number of questions about this subject of interest that still need to be answered, scientists have successfully made progress in classifying them. Let’s explore these classifications in detail, gaining a better understanding of them!

This category of black holes develops when huge stars, of approximately eight times the mass of our Sun, exhaust fuel. In such a situation, the star’s core caves in and may detonate into a supernova. If the surviving core is heavy enough- - approximately 20 solar masses or more- - it gets transformed into a stellar black hole.

These black holes are known to have different sizes, varying from a few times the mass of the Sun to many hundred times greater. They can grow larger by drawing in gas from neighboring stars or even combining with other black holes. Many stellar black holes have been discovered in binary systems, where they engage with neighboring stars, often producing X-rays in the course.

Massive galaxies, comprising our Milky Way, are known to have supermassive black holes in their middle. These black holes go up to millions and billions of times more than the Sun. For instance- - Sagittarius A, situated in our galaxy, is approximately 4 million times the mass of the Sun. Whereas, some supermassive black holes in other galaxies can be tens of billions of solar masses.


The formation of these massive holes is unclear to date. They may have formed early in the history of the universe manifested from the collapse of gigantic stars. They consist of the ability to grow by consuming neighboring material and joining together with other black holes during collisions.

Intermediate-mass black holes remain to be a bit of a mystery. They are believed to contain masses varying from hundreds to hundreds of thousands of times that of the Sun. These black holes might form from the uniting of stellar black holes or from the direct collapse of massive stars.


Scientists are efficiently investigating for confirmation of these black holes, but searching for them has been proven significantly difficult. Regardless of several candidates being proposed, validating their existence remains a substantial challenge.

Primordial black holes are believed to have originated in the very early universe, just seconds after the Big Bang. In specific circumstances, regions of dense material could have collapsed into black holes of different sizes. Some might be immensely small, at the same time, others could be even larger than the Sun.


Presently, there is no significant evidence that primordial black holes exist, considering they may have evaporated through the period. In contrast, more massive primordial black holes could still be out there, and scientists have been keen on exploring this possibility.