A Scientific Insight Into The Movie Interstellar

If you haven’t watched the movie Interstellar yet, I would urge you to watch it. I had been literally mesmerized by this mind-blowing work of Christopher Nolan and theoretical physicist Dr. Kip Thorne. I am not going to give a review of it here instead I intend to go inside it and tell what was really going on. Many of the things shown virtually in it are hypothetical but like Issac Asimov, an American writer and a professor of biochemistry at Boston university once quoted “Today’s science fiction is tomorrow’s science fact”, I would like to believe in most of those unfathomable things described in it.


In the Movie

In the movie, Cooper and his team with their spaceship Endurance set out to go through a wormhole near Saturn, opening a path to a fictional supermassive black hole called Gargantua which is located in a distant galaxy.

Black hole is an object which is so dense that not even light can escape its surface.

Regions of the black hole
Regions of Black Hole (Source)

There are mainly two parts to a black hole

  • Event horizon – is the boundary that marks where the escape velocity from the mass is the speed of light i.e. the “point of no return”.
  • Singularity – Once the matter is inside it, that matter will fall to the center called singularity where the mass resides. Due to strong gravity, the matter becomes almost massless and has an infinite density at the singularity.

Wormholes are formed by the merging of two far located singularities of two black holes.

In two-dimensional diagrams as depicted in the figure above, the wormhole mouth is shown as a circle. But when seen personally, it is a sphere, and Romilly explains it beautifully to Cooper in the movie. A gravitationally distorted view of space on the other side can be seen on the sphere’s surface.

The Reality

The reality is more intricate. The two key complications are

  • Size
  • Stability.

The primitive wormholes are prophesied to exist on the microscopic level. It is possible to be stretched to a larger size as the universe expands.

Stability plays another role as it collapse quickly. It is found that addition of exotic matter containing negative energy density and large negative pressure, it is theoretically possible to send information or travel across a wormhole.

If our present technology is boosted to super-super advanced technology, we can not only travel between two separate regions within the universe, travelling across two different universes might also be possible through the wormhole. And that’s not it, if one mouth of a wormhole is moved in a specific manner, it could allow for time-travel. Still, it would be a herculean task to turn a wormhole to a TIME MACHINE.


In the Movie

After reaching the other galaxy, they plan to investigate one among the twelve potentially habitable worlds located near the supermassive black hole Gargantua. The interesting part is that two of those planets orbit around Gargantua.

The Reality

Currently many studies are going on to find out whether a habitable planet can orbit a black hole or not. It is found that supermassive black holes have the potential for consuming everything in their path, from gas clouds to entire solar systems. According to thermodynamics, it’s the difference between the source of usable energy (the sun in the earth) and the sink for unusable waste heat (cold of space), that drives the processes that create life.

The black hole itself is a sink and Cosmic microwave background (CMB), which appears as a bright star just on the edge of the black hole’s shadow would serve as the source. To receive strong CMB radiations a planet should be present at the event horizon which we know is the point of no return and eventually the planet will be sucked in. But if the black hole spins really fast then close stable orbits are possible.


A conversation from interstellar

“Every hour we spend on that planet will be seven years back on earth. Well, that’s relativity, folks.” This is a dialogue from the movie about Miller’s planet, an ocean world which orbits around the Gargantua at its horizon, and a black hole that big has a huge gravitational pull. The reason behind the variation in time is time dilation i.e. a moving clock runs slower than a stationary clock or the faster you move through space, the slower you move through time. In this case, gravitational time dilation is the cause. It is a type of time dilation which is influenced by gravity. Higher the gravity slower the clock runs. We know that the force of gravity is stronger towards the surface of Earth than at a higher altitude. So, a free-falling object falls faster at a point on the surface, say A, than it does at a higher altitude, say B. For the free-falling object, according to Special Relativity, time at A must pass relatively slower than it would pass at B because the object’s velocity is faster at A.

Miller’s planet has a huge gravity when compared to earth and hence gravity on that planet will drastically slow down the clock with the crew and thus Cooper could age slower than his daughter, Murph, who lives on Earth. This is described as “twin paradox”, which means two twins born on the same date could have different ages if one were to travel near the speed of light while the other stayed on earth.


In the Movie

Skidding through the event horizon of Gargantua, Cooper and TARS eject from their corresponding craft and find themselves inside a gigantic tesseract, created by future humans, a civilization that has evolved past the four dimensions, the mysterious ‘bulk beings’ or ‘they’ in the movie.

The black hole’s gravitational singularity is manifested here as the tesseract where one can navigate both time and space dimensions. This is due to the strong gravitational field warping space-time onto itself which results in gravitational anomalies, for example, the dust particles which align themselves in some sort of compression and rarefaction in Murph’s room, the huge farming machines driving themselves (gravity affecting their guiding compass) towards their home, etc. The future Cooper uses gravity to manipulate the dust particles, thus giving the co-ordinates of NASA station to present-day Murph and Cooper.

So is harnessing the anomalies to lift colonies off Earth which was possible because Murph could solve the equation with the help of laws of quantum gravity that Cooper (inside tesseract) transmits into Murph’s watch (in earth) in morse code by manipulating the second-hand using gravity.

Quantum gravity is the study of gravity according to the principles of quantum mechanics, and where quantum effects cannot be ignored, such as in the vicinity of black holes where the effects of gravity are strong. In quantum gravity, our universe is considered as a membrane called brane residing in a higher-dimensional hyperspace called bulk. When we apply Einstein’s relativistic laws into this bulk the possibility of gravitational anomalies is found. These are anomalies triggered by the physical fields present in the bulk.

The Reality

The tesseract, even if such a place existed inside a blackhole, any living thing would be ripped off before getting to the singularity or even if they get in there, they won’t be able to escape from it and report what they saw.

'Somewhere, something incredible is waiting to be known' -Carl Sagan Click To Tweet

In reality the bulk, the gravitational anomalies and the harnessing of them are “speculations that can become educated guesses and then truth” in the words of Kip Thorne in his book “The Science Behind Interstellar”. I conclude by stressing on a quote by Carl Sagan that “Somewhere, something incredible is waiting to be known.”

4 thoughts on “A Scientific Insight Into The Movie Interstellar”

  1. So according to the “twin paradox”, the higher the gravity, the slower the clock runs. Now we all know that Elon Musk is preparing SpaceX to take humans to Mars within a couple of years where the gravity is 38% that of Earth. So, we will have experience time issues there. How do you justify that?

  2. According to gravitational time dilation, higher the gravity slower the clock runs. As mars have less gravity than earth, the clock in mars runs faster than the clock in earth. But there won’t be much difference as we see in the movie, as in the movie we are talking about the difference between gravitational pull in black hole v/s that of earth.
    By definition, a sidereal day on Mars is the length of time that it takes the planet to rotate once on its axis so that stars appear in the same place in the night sky. On Earth, this takes exactly 23 hours, 56 minutes and 4.1 seconds. In comparison, on Mars, a sidereal day lasts 24 hours, 37 minutes, and 22 seconds.

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