What Is a Black Hole

The start of a black hole’s life comes from the end of a very large star’s life. A black hole occurs after a supernova explosion. That star usually has a very big core. A star the size of our sun will end its life as a black dwarf, a medium-sized star will end its life as a neutron star, and a star many times the size of our sun will form into black hole. ( https://study.com/academy/lesson/black-holes-and-neutron-star-life-cycle.html )
Explanation: black hole
A black hole is a place or region of space where the gravity force is so strong that no matter can get out once inside, not even light. Since no light can get out of a black hole, it is invisible. Scientists use special telescopes and tools to spot black holes. Those special tools are also used to see how stars that are closer to black holes act differently than normal stars that are further away from black holes. A black hole is not just empty space. It is anything but that. A black hole is an area with a very large amount of matter packed into a small space. Black holes are so dense that they make ‘gravity sinks’.

Description: black hole
A black hole is a massive thing in space that is invisible to the human eye. A black hole cannot be seen because the gravity pull is so strong that it is pulling the light into the holes’ centre. A black hole is not black, as you would expect. It just appears black because no light can get out of it. ( https://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/what-is-a-black-hole-58.html )
Do Black Holes exist?
Yes, black holes exist! We have proof. Astronomers found evidence of a black hole that is massive in the centre of the milky way. Scientists had researched by studying a clouds speed orbiting around that specific region. There have also been many other black holes in the galaxy NGC 4258 etc. ( http://hubblesite.org/reference_desk/faq/answer.php.id=64&cat=exotic )
Event Horizon
An event horizon is the boundary defining the region of space around a black hole. It’s basically where one thing goes in, and it doesn’t come out again ( https://www.britannica.com/topic/event-horizon-black-hole ). The event horizon is the boundary marking the limits of a black hole, where nothing can escape once it goes in because nothing can travel faster than the speed of light, and as it states, nothing, not even light can escape a black hole. Which means it has to be faster than light to escape, physically nothing has been proven to be faster than the speed of light. ( https://www.quora.com/What-is-an-event-horizon-of-a-black-hole )
Why do scientists study black holes?
Scientists study black holes because they say it is connected to understanding gravity. Scientists say that it will help blind people have a better standard of living. ( http://curious.astro.cornell.edu/about-us/86-the-universe/black-holes-and-quasars/general-questions/440-why-do-we-study-black-holes-beginner )
Conclusion
In conclusion a black hole is a region in space that starts from a very large exploded star, where once something is in, it cannot get out. A black hole is invisible to the human eye because no light can get out of it.