Interstellar: Wormholes and Intergalactic Travel – B: The Movie

by

Howard Adelman

In the movie, Interstellar, the black hole, Gargantua, a hundred million times heavier than our sun (only a neutron star approaches it in weight), is used, not as a route of travel, but as a way of gaining propulsion, much as a slingshot works, by propelling the spaceship along its event horizon and back out in space at enormous speed. In the film, this occurs as a way of reaching and going through the wormhole and, again, in traveling from Miller’s planet to Mann’s planet, and, finally, to escape from Gargantua, the black hole itself into which Cooper falls.

In contrast to an event horizon, singularities include the sharply-pointed prime singularity where black holes terminate; they were formed when black holes formed. Eric Poisson and Werner Israel at the University of Alberta, postulated there may be a second singularity within a black hole that grows as the black hole ages, the infalling singularity. There is also an outlier singularity that was discovered two years ago by Donald Marolf at UC Santa Barbara and Amos Ori at the Technion in Israel.

Space and time are infinitely warped in the prime singularity. Einstein’s laws of relativity and quantum laws clash like the rough waters between the Scylla and the Charybdis. That singularity will guarantee your death before you could get to the terminus of a black hole. That is not necessarily true of a gentle infalling or outlier singularity. That’s how Cooper survives, by detaching himself and the Ranger from Endurance and plunging into the gentle outlier singularity rather than the primary or infalling one. The Ranger retained just enough thrust for it to escape the gravitational pull of Gargantua. Conceptually, this is a real stretch. Only in extreme theory would it be possible. Of course, if Cooper had fallen into the infalling singularity, he would not have been able to return to Earth for billions of years. Cooper had to be hit by stuff that fell before, not after, he fell in. And he is able to escape using Gargantua’s slingshot effect.

The problem of using black holes is twofold concerning both entry and exit. First, the nearest one, the one at the centre of the Milky Way galaxy, is still extremely far way. In contrast, it is theoretically feasible to find a wormhole within one solar system. That is not possible with a black hole. Secondly, in addition to the enormous distance to reach one, black holes are one way streets. Black holes can be used to escape this universe but never to return. Energy entering a black hole is trapped and condensed. There is no return voyage. Interstellar required a concept that allowed a spaceship to return, even if the passage of time of those aboard the spaceship was measured in hours while years passed on Earth. In fact, that difference in time is central to the dramatic core of the movie.

There are other problems in using wormholes than the ones mentioned above – aside from the fact that they exist only in theory. Even if one were discovered, would it still be in the same place by the time the mechanisms were created to travel through one. After all, the universe is a dynamic, not a static system. Even if the location of the wormhole remained relatively static, the energy dynamics might alter radically between the time the spaceship was launched and the time it took to reach the rim of the wormhole. For example, after launch, it took Ulysses sixteen months to reach the huge Jovian magnetosphere, the windsock formed around the planet Jupiter produced by its magnetic field. The magnetosphere changes in size and shape as it is blown by the solar wind, the outflow of magnetic gas traveling at speeds of 1.5 to 3 million kilometres per hour produced by the evaporation of the enormously hot (much hotter than the sun itself) and unstable atmosphere of the corona of the sun.

Thirteen years after Voyager I traveled to Jupiter, when Ulysses sailed past that planet on 8 February 1992, we discovered that the solar wind had died down. There had been something like a calm following a huge storm. At the same time, the size of the magnetosphere had ballooned. What might happen between discovering a wormhole, the time to prepare a launch and the time it takes to travel to the rim? How would a wormhole be altered by the changes in the character, speed and composition of the solar dust traveling in the opposite direction of our planets and asteroids? How would the possibility of reaching the rim of a wormhole be affected by the interstellar wind produced by the galactic cloud traveling usually at 50,000 mph, particularly as its speed and direction shifted? How would the changing turbulence of this interstellar cloud, which would probably travel in reverse direction to the spin of the wormhole just inside its edge, affect the possibility of a spacecraft traveling through a wormhole? These are among the many scientific issues Interstellar brackets. The movie already had a plethora of scientific issues on which to make a number of assumptions.

Thorpe doubted that the laws of physics would permit traversable wormholes to be created naturally– though this is the premise of the film. So why is it called science fiction and not science fantasy? Because, Thorpe argues, a wormhole could be created by a very advanced civilization. The members of that civilization – the undefined “They” in the film (they are our descendants who have become so advanced that they have acquired a fourth dimension of space) – were truly humanitarians. They developed the cosmological version of the United Nations High Commission for Refugees (UNHCR) by creating an exit route for suffering humans. Of course, whereas UNHCR exaggerates all the weaknesses of humanity, the movie presumes that this advanced civilization is not only phenomenally advanced intellectually, but compassionately as well. Now whatever the presumptions of this advanced civilization, it is not science fiction but science fantasy. No known laws of psychology and sociology make this version of an advanced civilization possible. But, of course, in defining science fiction, Thorpe meant possible according to the laws of physics, not possible according to the laws of psychology and sociology. But even according to the laws of physics, bulk with a fourth dimension of space would be curled. That is not in the movie. A curled bulk would have no impact on our four dimensions and pictorially would be a bore. Further, its depth would be so small, no human, as Cooper does, could perform any tasks in the fifth dimension (the fourth dimension of space).

One of the most interesting parts of the science in the movie concerns the character of the wormhole that allowed the spaceship to drop down into it. The movie makers gave the wormhole a weak gravity (in contrast to a black hole). So the Endurance could control its speed and direction in traveling through the wormhole. Further, according to Einstein’s Theory of Relativity, the weaker the gravitational pull, the slower time moves, but the difference is miniscule. Christopher Nolan postulated that one hour of travel in the wormhole was equivalent to seven years of time on Earth (the time dilation), a not scientifically impossible estimate for Miller’s planet which rotated around Gargantua with its enormous gravitational pull, even though Gargantua is located in the far reaches of the observable universe. Christopher Nolan found that it was impossible to apply the ratio to the rest of the trip. That is another reason to call the film a science fantasy rather than a science fiction, though Miller’s planet was not pulled apart by Gargantua’s enormous gravitational pull because its distortion was kept constant as its spin kept one side only facing Gargantua. At the same time, the picture of Gargantua, as seen from Miller’s planet, was very significantly reduced for aesthetic and/or dramatic reasons.

The speed of such a flight, even if inaccurate, was seriously altered. What about the width of the mouth of the wormhole or the distance from one end to the other? Unlike black holes, wormholes, like worms, have openings on each end. Envisioning the shape of the wormhole as a spool for holding thread with a fat axle was one of the great moments of the movie, especially given the distorted view of Saturn from its inside as if one were in a mirror maze in a carnival. However, when the moviemakers portrayed travel through the wormhole, the film abandoned science for artistic license to capture a feeling with which the audience could identify, even if that depiction of flight was impossible.

I will not go into detail into the most imaginative scientific extension of the movie, Michael Green and John Schwarz’s superstring theory. Nor will I deal with the visualization of four rather than three dimensions of space let alone the nine dimensions of space envisioned by the engineering of Endurance, especially in relationship to its landing craft, Ranger. The visualizations, particularly the huge waves encountered on Miller’s planet because of its proximity to Gargantua, were awesome. Those waves of over a kilometre high are scientifically realistic. The moon has a very weak gravitational pull. Yet, along the Petitcodiac River, off the Bay of Fundy and right into Moncton, New Brunswick, Canada, the water level rises 25 feet with the Tidal Bore twice a day. Think how much it would rise if the Tidal Bore were pulled by the huge gravitational force of Gargantua. Nevertheless, in spite of all the valid science, I believe I have made my point. Though I loved the movie, and though there was an enormous amount of real science packed into the film which I really appreciated, Interstellar should have been labeled a science fantasy and not a science fiction.

So probably should Interstellar II be labeled when Cooper sets off to rescue Brand from her orbiting on Gargantua’s horizon in the damaged Endurance.