Black Holes in Our Universe

THE DARK SIDE OF THE UNIVERSE        

Black holes. Don’t get fooled by the name, they are anything but space void.

INTRODUCTION

The universe is home to real monsters; we cannot see them however we know they’re out there. Black holes are the most mysterious phenomena in our universe. They are objects that are so compact which sequentially make their gravitational forces are unbelievably strong, causing the rules of gravity to be broken.

As per of their strong gravitational field, black holes have the ability to consume planets, stars and anything else which gets too close. Whatever enters a black hole cannot under any circumstances return and escape- not even light. As of this, people cannot see black holes; they are invisible. A black hole is virtually the end point of all matter, energy and gravity. Astronomers therefore have to use space telescopes with special tools to help discover and detect black holes. The purpose of this paper is to convey scientific information about black holes, in addition to how they rule the universe and take center stage.

TYPES OF BLACK HOLES AND THEIR STRUCTURE  

According to astronomers there are two distinct types of black holes, those of which are the Schwarzschild and Kerr black holes.

The core of the Schwarzschild black hole does not rotate on its axis and is considered as the simplest black hole. It consists of a singularity and an event horizon. The Schwarzschild radius is a measure of the distance to the singularity from the event horizon (see Figure 1 right). The quantity equation of the Schwarzschild radius is, where Rs = Schwarzschild radius, G = gravitational constant, M = mass of the black hole and c = speed of light.  It is proven that if an object has a radius smaller than its Schwarzschild radius, it is a black hole.                                                         Figure 1: Anatomy of a Schwarzschild Black Hole[pic 2][pic 1]

On the other hand, the naturally more common; Kerr black hole rotates on its axis. This can be explained with the formation of the black hole (read FORMATION section) from an exploding star; when the star dies out forming a black hole, the core still continues to rotate. The Kerr black hole consists of the; [pic 3]

• Singularity = The collapsed core of the massive star, also known as the point of no return.         Point of infinite density and gravity.                        
• Event horizon = Boundary limit of escape velocity            

greater than the speed of light. It is not a physical                         Figure 2: 3D diagram on black hole regions surface, it’s not even noticeable however all

known matter, energy or radiation are drawn into the

singularity if passed beyond this boundary.[pic 4]

• Schwarzschild radius = Measure of the distance to the singularity from the event horizon.
• Ergosphere = Region of space where all particles are drawn in a spherical path that matches the hole’s rotation.
• Static limit = Outer edge of the ergosphere. The distance which matter must preserve in order to hold a constant orbit and not be overwhelmed by the hole’s rotation.                                                                             Figure 3: Anatomy of a Kerr black hole              

See figures 2 and 3 for more clarification on the properties of a Kerr black hole.

BIRTH AND FORMATION

The birth of a black hole occurs when a large star is unable to withstand the compression of its own gravity. This happens when the nuclear fusion inside the core runs out of fuel and explodes as a supernova.

While massive stars are alive the forces of gravity that attempt to collapse the star are immense. These forces pulling inwards are cancelled out by the giant fusion reactions taking place inside the core which are trying to explode the star. Ultimately the star neither explodes nor compresses as the opposite forces balance each other out.

However in the process of a dying star, the fusion reactions stop and there is no outward force. Taking advantage of this, gravity wins and pulls the star’s materials inwards, compressing it so much that the dense core heats up and explodes causing a supernova. Subsequently a highly compressed and dense core with a gravity so strong causing nothing - not even light to escape is remained.  

This core completely vanishes out of sight as of its infinite gravity and because no light can escape it stays indiscernible. The dense core sinks through the fabric of space and time creating a hole where no return is possible. Thus the name; a black hole.

SIZE, MASS, VOLUME AND GROWTH

Black holes vary in size, ranging from colossal to microscopic. Astronomers and scientists together believe the smallest of all black holes are approximately as small as a single atom. Seeming tiny, these black holes however have masses equivalent to mountain ranges. Supermassive black holes that are colossal in size have masses equivalent to more than 4 million suns combined.

Since black holes squeeze all their matter into such small regions they have a substantially small volume. By capturing nearby material, black holes increase in mass. Notwithstanding their repute, they do not draw in matter from large distances, but rather only capture material nearby.