Few sci-fi movies have bothered trying to be scientifically accurate. Even science fiction novelists did most of their work as speculative fiction, not knowing the complexities of their interesting ideas, and not having the access to information needed to make certain aspects work. But as the age of information has dawned and risen, the ability to get the physics right, and the imperative need to get the physics right, has driven sci-fi creators to care more, and do more, as they create new narratives. Two major blockbusters in the past ten years stand out as having done more than the rest: Interstellar (2014) and The Martian (2015). Which one takes the cake as the most accurate to reality? Read through to find out.
Twentieth Century Fox, TSG Entertainment, Scott Free Productions,
What they got right:
What The Martian got right:
- Growing potatoes from the soil and human compost
- Radiation sickness not affecting him during his time away from Earth
- Inflatable habitats on Mars
- Martian landscape and tornadoes
- How gravity affects space flight
Getting into it:
- Growing potatoes from the soil and human compost
This is realistic as long as the soil is amended, Martian soil composition shouldn't be too bad for growing plants on Mars. According to NASA, soil on Mars does contain all of the major micro and macro nutrients, such as Carbon, Nitrogen, Iron, Manganese, and so much more. It might not be in the correct quantities, so when Mark amends the soil with human compost (which is even used on Earth), he's being realistic in his farming endeavors.
- Radiation sickness not affecting him during his time away from Earth
While the radiation on Mars would mean that astronauts would live underneath the surface in order to provide some shielding, the fact that Mark spends his time on the surface is not unrealistic. For one, he would not be able to dig into the surface in a meaningful way without proper equipment. He also doesn't need to worry about the short term effects of extra radiation. In the time he spends on the surface of Mars, it's pretty unlikely that he would develop cancer or other forms of radiation poisoning, as we are fairly sure the exposure on Mars won't be that extreme.
- Inflatable habitats on Mars
This is totally happening. As in, this is currently being developed by NASA as the long-term solution to housing on Mars and other surfaces. That said, the shapes of the shelters might be a little different due to the air pressure needed inside being so much greater than the atmosphere pressure of Mars. Overall, this is a realistic feature of the movie.
- Martian landscape and tornadoes
The movie portrayed colors, desert conditions and most of the weather fairly accurately (the first big dust storm is the exception). The surface of Mars totally has really large dust devils occurring. One has even been recorded visually by the Rover program!
- How gravity affects space flight
Not only do they use accurate maneuvers to navigate space, they also accurately portray how long it will take to reach Mars. Since gravity has an inverse relationship with distance, this is directly related to how long it will take to reach Mars, as well as how important approaching the planet correctly is.
What Interstellar got right:
- Time dilation near the black hole
- Gravitational lensing and its visible appearance
- Solar-powered drones on Earth
- Space travel and realistic time frames
- Doughnut-shaped space vessel is based on valid theories
Getting into it:
- Time dilation near the black hole
Due to time dilation, gravity, especially gravity from incredibly large masses like black holes, will massively (get it?) increase the velocity of the spacecraft, and added velocity will mean that time is dramatically slower for the spacecraft than it is on Earth.
- Gravitational lensing and its visible appearance
Interstellar was careful to be accurate about existing black hole simulations. While they certainly made it look a little more dramatic, when you look at the most up-to-date simulations, it's a pretty good facsimile.
- Solar-powered drones on Earth
We are already seeing solar-powered drones on Earth, and the idea that they could last a decade before coming down is pretty reasonable. I mean, especially if Apple started building the drones and knew they wouldn't get another contract for a full decade, it's reasonable that this would happen.
- Space travel and realistic time frames
Just like The Martian, Interstellar takes into account reasonable times for space travel. That said, they do go a little fast while within our solar system. On the whole, it's fairly realistic before they reach the black hole.
- Doughnut-shaped space vessel is based on valid theories
The Stanford torus is a concept of a rotating wheel space station to simulate gravity artificially proposed during the 1975 NASA Summer Study. While there have been a lot of discussions about the pros and cons of various space station designs, this one has gotten a lot of attention by scientists and is a reasonable idea.
Twentieth Century Fox, TSG Entertainment, Scott Free Productions,
Where they went wrong:
Where The Martian went wrong:
- The major plot point of the dust storm couldn’t have caused that much damage.
- It’s expected that shelters on Mars will be underground to minimize radiation exposure.
- Take off from Mars
- Walking on Mars
Getting into it:
- The major plot point of the dust storm couldn’t have caused that much damage.
Sure, dust storms happen all the time on Mars, but the reality is that it is atmospheric pressure that makes dust storms dangerous on Earth. Without a lot of atmosphere, the storms on Mars have all the inertial capability of a moderately windy day. It could blow some things around if they are light enough, but honestly, it's not going to have disastrous consequences. Andy Weir himself has mentioned he used it to drive the plot.
- It’s expected that shelters on Mars will be underground to minimize radiation exposure.
While short term exposure is not a large concern, long term shelters are still expected to be created underground to shield inhabitants from the Sun's radiation. Why does Mars have that much more of a radiation issue? On Earth, our atmosphere does a pretty good job of shielding us, but Mars doesn't have near as much of an atmosphere.
- Take off from Mars
This point is a little weak, and it is mostly a concern because we have issues with take off on Earth. We still have catastrophic events here, and since the conditions on Mars are not something we can recreate here, we really don't know what take off will look like on the Red Planet.
- Walking on Mars
Scientists are envisioning something between a hop and a shuffle, which will look hilarious when we really do get to Mars.
Where Interstellar went wrong:
- Anything with their gravity equation
We already have a pretty good gravity equation, and it's good enough to simulate the visuals used in the movie for the black hole visualization. The fact that they used existing science so heavily, but directly claim that the existing equation is not accurate, is just one of those shake-your-head moments for scientists.
- Anything with their wormhole and time travel
Please, visualize the word spaghettified. Then, attempt to imagine anything trying to exist after being spaghettified. Yeah, no wonder they have aliens showing up in the fifth dimension to fix everything. Our science doesn't know everything, but it definitely does not know how to undo spaghettification.
- Collecting data from a black hole
You can't collect data from a black hole, because data is transmitted by matter or waves, neither of which can escape a black hole.
- Frozen clouds
This one might seem plausible, but there's nothing known that would allow for density to work this way.
- Planets forming that close to a black hole
Anything forming that close to a black hole would be ripped apart violently. Think about how far Earth is safely situated from our Sun. Then imagine if our Sun suddenly gained the mass of a black hole, and how far we'd have to be from that to be safe.
- Those crazy waves on that planet
Those waves don't make sense. If they were from a tidal force, the planet would have a large bulge. If they were from winds, the planet would need a different atmospheric pressure to actually create them. And since they are regularly occurring, they aren't likely to be tsunamis from tectonic plate activity.
Twentieth Century Fox, TSG Entertainment, Scott Free Productions,
The Science Showdown
Since The Martian and Interstellar portray very different aspects of similar ideas, there aren’t a lot of 1:1 comparisons. The stories these rights and wrongs tell can be hard to draw a line. For example, a third of Interstellar deals with inter-dimensional travel, and most of the Martian is physically on Mars. That said, it's worth an in-depth look where the movies overlap! How do they really compare on the points that they do both cover?
Paramount Pictures, Warner Bros., Legendary Entertainment
The Weight of Gravity
Both movies deal with gravity as a major question. Interstellar has a “gravity equation” which tries to sync quantum mechanics to our existing understanding of gravity. That said, our understanding of gravity is actually pretty well built out in reality. We already have the equations of general relativity, string theory and loop quantum gravity, all of which have brought us to the conclusion that there isn’t one equation that will explain everything. However, that doesn’t move plot points, so Interstellar decided that the gravity equation would have to do.
The Martian doesn’t try to deal with gravity in quite the same elegance, so it’s no surprise they win this round. They use the Rich Purnell Maneuver, which is based on gravity-assist trajectory theory from the NASA Voyager launches. That said, they aren’t flawless in their gravity handling. The Red Planet has around 30% of the gravity that Earth has, making a lot of the little things different on Mars. What could we possibly be talking about? Walking. Walking would be way different according to NASA, who believes the best and easiest way to walk will be something between a shuffle and a hop, very different from the movements that Mark Warney makes in the movie.
Paramount Pictures, Warner Bros., Legendary Entertainment
How Hard is Space Travel?
It’s fairly easy for audiences to accept that space travel in the future will look different and be faster than it is right now. That said, most sci-fi shows don’t bother to even try to make it look like a realistic progression from what we have now. In Interstellar, Christopher Nolan consulted with theoretical physicist Kip Thorne to attempt to stay accurate to what we currently know about wormholes and relativity. Most of the space travel experience shown is relatively accurate. You know, up until the wormhole and the time travel nonsense. At that point, the spacecraft would have been spaghettified and decimated. Their matter would never have left the black hole. Time travel wouldn’t work that way. There’s a number of issues at this point. On top of that, not having a flight plan is actually insane. If it were NASA, they would have had a million contingency plans, at least two for each potential planet, and even if it weren’t set in stone before launch, the astronauts were in contact in the solar system for two years, and plans could have been uploaded at any point.
In the Martian, the space travel looked a lot like it does now. Weir did not invent any fancy hyperspace drives or Faster-Than-Light travel in order to hurry the story along. He made his characters go through the same eight month flight as the rovers do now. Kudos to the Martian on this one. That said, take off is a bit of an issue with the movie. The Mars Ascent Vehicle (MAV) makes fuel out of methane in the atmosphere and then rockets the MAV up to the Hermes spacecraft. On Earth, we have a rocky enough time with take off launches. Mars has 30% of the gravity that Earth has, and a very different and large atmosphere. NASA is hoping to send something to pick up and return samples prepared by the 2020 rover Perseverance, but there’s still a lot to be learned and done by scientists before they have any idea what take off on Mars will look like. Looks like space travel ends up as a tie between the Martian and Interstellar until scientists learn more about wormholes and take off.
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And the winner is …
The Martian. Andy Weir gave filmmakers a great start with his book, and he was onboard to make sure the science stayed as sound as possible. Great job to everyone involved in this movie; it will be on course curricula and playing in the background of science student lounges for ages.
