Interstellar #1

From the limited knowledge I gained in the past couple years I have been able to understand Interstellar and I would like to impart the knowledge to everyone who's eager to understand the movie. The explanation is in 4 parts: First we learn about the big terms and their meanings, Then we talk about the two major moments in the movie that confused everybody and finally the questions that arise once you've understood what you've seen and an attempt to try and answer them yourself. So in this first post lets see about those big terms.

- Wormholes are a purely theoretical concept which exist only as mathematical equations and in science fiction. They're a shortcut through space-time which enables us to cover greater distances in space. Its highly improbable that a wormhole exists in space that would allow such a travel.

- Black holes are real and they do exist in the observable universe.

*Contrary to popular belief they're not holes in the middle of the universe

*They're not stars that have burst/ exploded and left a gap in the middle of the universe

*A black hole is a star that has expanded beyond a certain critical mass, which resulted in its gravity increasing exponentially and due to such gravitational pull its impossible for anything (including light, the fastest observed wave/particle in the universe) to escape from the surface of it. Since there's no light being emitted from it, it has to appear like a black gap in the middle of the universe (which has been visually imagined in this movie)

- Event Horizon is usually recognized as the space surrounding the black hole. where the pull of gravity is infinity.

- Singularity is a tiny point in space where density of matter is infinity and time didn't exist. It is believe that the universe came to be, from such a singularity.

-Theory of relativity : Time is relative, the reference of time differs from observer to observer based on the point from where they're observing it. Time is faster for astronauts in orbit and comparatively slower for observers on earth. To understand this concept let's consider an illustration from "The Grand Design" which goes like this.

(this example is not to be confused over the train example for inertia) : person A is bouncing a ball while travelling on an airplane, when the ball hits the ground and bounces back, for an observer inside the plane (A) the ball has not traveled any distance over time. It has just gone down and bounced back to his hand. But for an observer on the ground (person B) watching the ball bounce inside the plane, when the ball went down and bounced back up it has travelled from position x --> y over time. So the flow of time appears different for every observer based on the point of observation.

- And finally, gravity stretches time through space. If you're on an object in space that exerts high gravity like a black hole, for an observer on the black hole time runs at the same speed as before entering it, but for an observer from outside the black hole, time stretches and expands and hence appears to have moved faster (and hence have run longer) with reference to the person on the black hole.