Black Holes

I recently watched the "Chrsitopher nolan" movie INTERSTELLAR and there were somethings about black hole that i quiet didn't understood.Then i came to know many other people were having this problem,so this post is to you guys

• Astronomers have spent much time analysing how stars form and how they develop.One problem was to explain what happened to a massive star at the end of its life.
• In 1967 the term "black hole" was used to describe one type of object that is left when a massive star dies.
• Four years later,Cygnus X-1 was found,the first candidate for a black hole

 1.DETECTING A BLACK HOLE 

• Black holes appear black because nothing,not even light, can escape from their gravity.
• Astronomers cannot detect them directly, but can "see" them because of the effect their gravity has on everything around them,such as gas from a nearby star.
• The boundary of the black hole is called event horizon.

2.ENTERING A BLACK HOLE

1.   At the start of the fall, everything appears normal.
2. As the astronaut approaches the hole, he starts to be stretched.
3. Light is also stretched to a longer wavelength so the astronaut appears redder
4. Gravity stretches the astronaut.Close to the hole, he is torn apart

3.INSIDE A BLACK HOLE

• Space and time a highly distorted inside a black hole.
• Anyone unlucky enough to fall into one would be stretched to resemble spaghetti, as gravity pulled more on the feet than the head.
• An observer watching the person fall would also see time running slower as the person fell towards the event horizon 

Roger Penrose 

• The English mathematician Roger Penrose (b.1931) theorizes on the nature of space and time
• He has shown that a massive collapsing star inevitably becomes a black hole, and that all black holes have a singularity point, occupying no virtually no space,that contains the entire mass of the dead star
• Penrose believes the singularity is always hidden by an event horizon