Once again, Chris Nolan shows us why he is being hailed as one of the best directors working today. Interstellar confused people in a good or bad way. People loved it or hated it, I personally loved it. So if you are one of those who didnt understand the movie, I have an explanation of Interstellar movie for you. I have watched Interstellar more than 3 times and thats how I wrote this article. I have written this on Quora and received a good response so I am sharing it here.
I am assuming that you know the plot. Crops on earth are dying. Humans have to find a planet where they can live. They sent several missions and 3 of them are sending a signal back. So there is a chance that those planets might be habitable. Now all we have to do is go there and check . Dr. Brand chooses COOP do to this (I will explain, how). He has two plans in mind that will ensure the survival of humans.
· Plan A): while the Endurance team (Coop and his friends) is away, Brand will continue to work on an advanced equation that, if solved, will allow humans to harness fifth-dimensional physics – specifically gravity. Should Brand succeed, NASA will be able to defy our traditional understanding of physics and launch an enormous space station (carrying the remainder of Earth’s surviving population) into space. We will be able to control gravity so Earth’s gravity will not have any effect on us. The very facility that Cooper and Murph stumble upon at the beginning of the film isn’t just a NASA research station, it’s a construction site for humankind’s space-traveling ark.
· Plan B): Should Brand fail in his calculation and/or the Endurance take too much time investigating potential home worlds, NASA has harvested a bank of fertilized human embryos that can be used to ensure humanity’s survival – after everyone on Earth is wiped out. To ensure genetic diversity, NASA procured DNA from a wide range of sources so that future generations would not be limited to reproduction between Endurance crew members. In this scenario, the Endurance team would settle down on the most habitable planet and raise the first generation of embryos, with each subsequent generation helping to raise a new set of embryos (as well as reproducing naturally).
Dr. Brand knew that Plan A was not possible but he didn’t tell it to anyone. He knew that coop wouldn’t go if he tells him the truth. He tried to solve the equation for many years but couldn’t succeed as he was missing something, an important part of equation. The only possible way to solve that equation was to go inside the black hole and get the singularity data because black hole is the only place where gravity is infinite and singularity exists. So he wanted them to follow Plan B. But coop takes a risk that changes everything. He decides to go inside the Black hole to get the singularity data which was needed to solve the equation. He didn’t know what was going to happen to him and neither did we.
He goes inside the black hole and finds himself within a Tesseract now this Tesseract is a five-dimensional space. You can control 5 dimensions (including time and gravity) inside this Tesseract. It is a 3D representation of a 5 dimensional space. The question is – who placed it here inside a black hole? The answer is – WE, The future humans. They wanted cooper to communicate with his daughter with the help of Tesseract. As there is no other method through which you can send the data back to earth from another galaxy. Gravity can pass through dimensions so the Tesseract was a medium.
Here Cooper can control the time and gravity and jump to a particular time instant. This is what he does. He was the ghost all the time. He tells the coordinates of NASA in binary form (TARS knows everything, doesn’t he?) to his past self by creating gravitational anomalies (as gravity can be controlled within the Tesseract and it can pass through dimensions), then TARS gives him the singularity data and he feeds this data to the second hand of the watch (MORSE code) by altering the gravitational field. This is how he communicated with his daughter.
His daughter solves the equation with the help of this data and they are able to manipulate gravity. The made the space ark (and stations) with the help of the new understanding of physics and left earth before all the crops died. There are hundreds of such space stations. Cooper station is one of these space stations.
Now, Dr. Amilia Brand reaches Edmunds and she finds that the planet is habitable but she does not know if coop was successful. So she follows plan B to ensure the survival of humans and now we have two races of humans living on Space stations and Edmunds.
The question that most people ask is – how did the humans survive in the first place to master five-dimensional physics and place the tesseract inside the black hole for their own survival.? Well, this is called Bootstrap paradox, read about it here ->
Now read another theory which blew my mind and could be true.
The mission was a failure, coop died in the black hole (there was no tesseract), humans (on earth) died and the humans on Edmunds survived (Because they were taken to Edmunds by Amelia). They grew up and mastered the five-dimensional physics. So they are “THEY”. They did everything – placing the Tesseract inside the Black Hole (They can do this because they have mastered gravity). They did all of this because they wanted to help the humans on earth who died a long time ago.
Hope this helps. This is the best that I could do.