Realistic Science Fiction: What did Interstellar/the Martian get wrong?

[manaiaK]

Interstellar:

A planet closely orbits a black hole without being torn apart by tidal forces. A guy goes into a black hole without being shredded into sub-nuclear particles. He survives pretty much unaided in some kind of >4 dimensional mystical maze, and comes out of it whole and unharmed.

Earlier, people fly around in spaceships with ridiculously high Isp and thrust and ridiculously small mass ratios, as though they're designed to go down the road to the chemist's.  These spaceships (word used advisedly) must be able go at super-light speed to be able to get around a "galaxy full of habitable planets" inside a human lifetime, however extended.  Space is big, people. It takes a looooong time to get between stars.

As for wormholes: they are just conjecture, not even theory. The people doing the conjecturing are smart, but they are speculating well outside the limits of their knowledge. If wormholes exist, the same considerations are likely to apply as with black holes: send some baryonic matter in, get quarks or just gamma rays out, however "big" the wormhole might appear.

Interstellar is pure fantasy.

As you might have guessed, I was disappointed with Interstellar given how it was hyped as a hard science movie.  The Martian is still the only such movie I have have seen that involves spaceflight, despite its inaccuracies.

[AngelLestat]

Something that is much much worse than a movie breaking physics laws or logic, is an audience criticizing the things that in fact are correct but they were too blind to not notice it or at least try to imagine a scenario where it can work.   

[Geher]

9 hours ago, manaiaK said:

As you might have guessed, I was disappointed with Interstellar given how it was hyped as a hard science movie.  The Martian is still the only such movie I have have seen that involves spaceflight, despite its inaccuracies.

And what do you think about Apollo 13?

[billbobjebkirk]

16 hours ago, manaiaK said:

Interstellar:

A planet closely orbits a black hole without being torn apart by tidal forces. A guy goes into a black hole without being shredded into sub-nuclear particles. He survives pretty much unaided in some kind of >4 dimensional mystical maze, and comes out of it whole and unharmed.

Earlier, people fly around in spaceships with ridiculously high Isp and thrust and ridiculously small mass ratios, as though they're designed to go down the road to the chemist's.  These spaceships (word used advisedly) must be able go at super-light speed to be able to get around a "galaxy full of habitable planets" inside a human lifetime, however extended.  Space is big, people. It takes a looooong time to get between stars.

As for wormholes: they are just conjecture, not even theory. The people doing the conjecturing are smart, but they are speculating well outside the limits of their knowledge. If wormholes exist, the same considerations are likely to apply as with black holes: send some baryonic matter in, get quarks or just gamma rays out, however "big" the wormhole might appear.

Interstellar is pure fantasy.

As you might have guessed, I was disappointed with Interstellar given how it was hyped as a hard science movie.  The Martian is still the only such movie I have have seen that involves spaceflight, despite its inaccuracies.

You completely misunderstood everything about Gargantua. It doesn't rip Miller's Planet or Cooper apart because it's a high mass black hole, which means it has a wider event horizon and far weaker tidal forces. Cooper does not survive unaided, he is removed from the black hole by the 5d beings. The spacecraft in Interstellan never perform intestellar travel, but rather explore the planets and stars in near orbit of Gargantua. As for it being conjecture, that's the whole point of the movie. It's meant to straddle right on the edge of our current knowledge of physics, showing us five-dimensional phenomena that theoretically could happen if we assume the existence of a fifth spatial dimension.

Edited December 4, 2015 by billbobjebkirk

[Hobbes Novakoff]

Here's something that's bugged me about The Martian. So, about halfway through the movie, one of the hab's airlocks explodes for Reasons, killing Watney's plants and generally causing Bad Things to Happen. Watney fixes the damage with what appears to be plastic sheeting and duct tape. The moment I saw that scene, I went "What? That sheeting is way too weak!" So, I ran the numbers. Judging by this image, the airlock tunnel is about six feet in diameter, or 72 inches. This works out to a radius of 36 inches. If we calculate the area of the sheeting with the equation a = πr², we find that the sheet is about 4071.5 in² in area. (For simplicity, I'm not accounting for the bulge visible in many of the scenes.) We can assume that the hab was pressurized to slightly lower than Earth atmospheric pressure. Let's assume it was pressurized to the pressure of an airliner cabin, about 11 pounds per square inch. Now, if we do the math, we find that that sheeting was withstanding about 45 thousand pounds of air pressure. (About 20 thousand kilograms.) In other words, that sheeting was withstanding the force of about nine fully grown Asian elephants standing on it. There is no way that that tarp is withstanding that kind of force.

(Note: I am not an engineer. Feel free to correct me.)

[SomeGuy123]

In the book it was made of like carbon nanotube weave.  It wouldn't have been transparent, would have been thicker, and it was made of the same stuff the rest of the Hab was made out of.

There are fabric meshes that can withstand air pressure : Bigelow aerospace has some.  Note they have actual orbiting stations they have inflated to test this.

[andrewas]

Its supposed to be hab canvas, a heavyweight fabric used for the hab's entire outer shell. And he glues it down using a resin specifically designed for sealing canvas to canvas well enough to hold an atmosphere of pressure.In the film? Polythene sheeting and duct tape. And it flaps in the wind, at one point even blowing inwards, despite that it was supposed to be holding an atmosphere at that point.

[Hobbes Novakoff]

2 hours ago, andrewas said:

Its supposed to be hab canvas, a heavyweight fabric used for the hab's entire outer shell. And he glues it down using a resin specifically designed for sealing canvas to canvas well enough to hold an atmosphere of pressure.In the film? Polythene sheeting and duct tape. And it flaps in the wind, at one point even blowing inwards, despite that it was supposed to be holding an atmosphere at that point.

That makes much more sense. I think there's a bit of artistic license going on there, to keep the "held together by duct tape" theme going.

[manaiaK]

16 hours ago, Geher said:

And what do you think about Apollo 13?

I haven't seen it.  Is it good?

9 hours ago, billbobjebkirk said:

You completely misunderstood everything about Gargantua. It doesn't rip Miller's Planet or Cooper apart because it's a high mass black hole, which means it has a wider event horizon and far weaker tidal forces.

Yes, that could work if its event horizon was more than a light-year across. It wasn't.

[billbobjebkirk]

3 hours ago, manaiaK said:

I haven't seen it.  Is it good?

Yes, that could work if its event horizon was more than a light-year across. It wasn't.

Gargantua is 100 million solar masses. The tidal forces at the event horizon are minimal. The forces from the upfalling singularity are not, which is why the Ranger is torn apart, but Cooper survives due to the square-cube law.

[ZetaX]

13 hours ago, manaiaK said:

Yes, that could work if its event horizon was more than a light-year across. It wasn't.

No. Here is problem sheet for you: http://spacemath.gsfc.nasa.gov/blackh/4Page33.pdf .

[manaiaK]

On 5/12/2015, 3:33:17, billbobjebkirk said:

Cooper does not survive unaided, he is removed from the black hole by the 5d beings.

This actually makes the film worse. Otherworldly beings with great powers who help humans? That's the definition of elves. Put elves in space, they're still elves. A plot that relies on the presence of elves is not remotely conjecture; it's fantasy.

 

16 hours ago, billbobjebkirk said:

Gargantua is 100 million solar masses. The tidal forces at the event horizon are minimal. The forces from the upfalling singularity are not, which is why the Ranger is torn apart, but Cooper survives due to the square-cube law.

This was all thrashed out in the 1980s. 10⁹ solar masses might allow the persistence of simple molecules of baryonic matter. No guarantees about larger structures. To safely get a human through the event horizon, you need a big black hole.

More prosaically, different parts of the known universe have great relative velocity. I saw no attempt to account for that, either looking through the wormhole or travelling through it.

Light from surrounding stars falling into a large black hole is going to be heavily blue-shifted. Any orbiting planets will be bombarded with hard radiation, no matter their magnetic fields. Looking in different directions while on the time-dilated planet, the people should have seen red-shifting and blue-shifting. I don't recall much of that.

Edited December 5, 2015 by manaiaK

[billbobjebkirk]

You are right about the red-blue shift, I will give you that.

[SomeGuy123]

On 12/3/2015, 5:52:00, AngelLestat said:

Something that is much much worse than a movie breaking physics laws or logic, is an audience criticizing the things that in fact are correct but they were too blind to not notice it or at least try to imagine a scenario where it can work.   

So, how does a rocket ship without significant propellant tankage work?  I just can't quite seem to imagine how..

How does someone decode the signal from a timeshifted probe without noticing the massive timeshift?

Isn't descending into a time dilation field in a gravity well a process that requires incredible velocity change, in that same way that actually crashing into the sun in a spacecraft is incredibly difficult?

Edited December 6, 2015 by SomeGuy123

[Robotengineer]

Fantasy-ness of sci-fi (IMO): Star Wars, pure fantasy --> Star Trek, slightly less pure fantasy, --> Gravity, fantasy physics, --> Interstellar, less fantastic than Gravity in parts, more fantastic in other parts, --> The Martian, mostly real physics, though some real things are ignored...

 

 

...Real Life.

Edited December 6, 2015 by Robotengineer

[Kerbart]

On 12/4/2015, 3:04:27, Geher said:

And what do you think about Apollo 13?

One can argue that Apollo 13 wasn't Science Fiction.

However, I think that 2001 was pretty accurate in how spaceflight was handled. Perhaps even more so. Of course there's the scene at the end, but I think we can safely square that away under “suspension of disbelief” as it was a plot element, just as what Cooper was doing inside the watchimacallit in the black hole; it's part of the plot and it is a Science Fiction movie after all.

Hate it or love it, Apollo 18 was accurate in it's depiction of space flight (again, disregarding what's covered under suspension of disbelief because it's part of the plot)

Europa Report did a good job at keeping things realistic, I think.

When wandering down the path of obscure movies or semi-obscure movies (the 1968 version of Polaris comes to mind) it's really not that hard to find movies that show a fairly realistic depiction of space flight. Mainstream is a different story.

[AngelLestat]

1 hour ago, SomeGuy123 said:

So, how does a rocket ship without significant propellant tankage work?  I just can't quite seem to imagine how..

How does someone decode the signal from a timeshifted probe without noticing the massive timeshift?

Isn't descending into a time dilation field in a gravity well a process that requires incredible velocity change, in that same way that actually crashing into the sun in a spacecraft is incredibly difficult?

1-Its mention in the same movie, they use a neutron star as gravity assist to reach miller´s planet and for go back to the endurance.

For this we need to remember that miller´s planet is traveling at 0.45c, but the wormhole is also orbiting the black hole. In the book kip thorne said that a neutron star will not be enoght to the manuver because it would break the ship, that he will needed another black hole (instead the neutron star) orbiting gargantua, but Christopher Nolan dint wanted 2 blackholes because it would be confusing for the audience. 

 

2- You mean decoded from earth or the endurance?

From the endurance they knew that the planet had a huge time shift, but I guess that in earth they dint know, they just knew  that 3 astronauts saw 3 potential worlds. 

 

3-  Gargantua is a rotating black hole spinning at 0.999999999 the speed of light, in fact almost all supermassive black holes rotates at average 0.9999 the speed of light because each piece of matter that falls increase their speed, but this particular black hole was even faster.  This rotation drags spacetime with it, and miller orbits gargantua in opposite direction of its spin. 

The black hole from the movie would look like this (this images is not a full render, it lacks brights and colors), but Nolan was in love from the full ring bright look.

   

A rotating black hole It has 2 photon spheres, that´s why is so wide in the picture the photon sphere.

 

Then you must be wonder on all the deltav maneuvers on mans planet, this is not mention in the movie, but mans planet has a orbit very eliptic, from 600 au to 5 au from the black hole,  So if you are in the far from the periapsis, just a little change in your orbit can take you to the black hole.

Edited December 6, 2015 by AngelLestat

[Geher]

On 5.12.2015 01:05:15, manaiaK said:

I haven't seen it.  Is it good?

If you liked the Martian then you'll probably also like Apollo 13.
https://xkcd.com/1536/

It is also very accurate regarding the science.

[SomeGuy123]

On 12/5/2015, 11:37:53, AngelLestat said:

1-Its mention in the same movie, they use a neutron star as gravity assist to reach miller´s planet and for go back to the endurance.

For this we need to remember that miller´s planet is traveling at 0.45c, but the wormhole is also orbiting the black hole. In the book kip thorne said that a neutron star will not be enoght to the manuver because it would break the ship, that he will needed another black hole (instead the neutron star) orbiting gargantua, but Christopher Nolan dint wanted 2 blackholes because it would be confusing for the audience. 

 

2- You mean decoded from earth or the endurance?

From the endurance they knew that the planet had a huge time shift, but I guess that in earth they dint know, they just knew  that 3 astronauts saw 3 potential worlds. 

 

3-  Gargantua is a rotating black hole spinning at 0.999999999 the speed of light, in fact almost all supermassive black holes rotates at average 0.9999 the speed of light because each piece of matter that falls increase their speed, but this particular black hole was even faster.  This rotation drags spacetime with it, and miller orbits gargantua in opposite direction of its spin. 

The black hole from the movie would look like this (this images is not a full render, it lacks brights and colors), but Nolan was in love from the full ring bright look.

   

A rotating black hole It has 2 photon spheres, that´s why is so wide in the picture the photon sphere.

 

Then you must be wonder on all the deltav maneuvers on mans planet, this is not mention in the movie, but mans planet has a orbit very eliptic, from 600 au to 5 au from the black hole,  So if you are in the far from the periapsis, just a little change in your orbit can take you to the black hole.

Some nice images.

But woefully short on facts.  How much dV do you need to transfer orbits in a black hole, to a level powerful enough that time is distorted?

How do you explain them able to decode the beacon at all and be unaware of the time dilation?  Do you even understand the concept of a frequency shift?

How do the engines on the ships work?

[AngelLestat]

How I said, it depends on the black hole itself and how fast is rotating. Kip thorne in his book also explain in detail how to steal energy from a rotating black hole using the ergosphere. For example if you have 2 massive black holes orbiting on each other, with a ship you can travel between the different ergospheres many times until you leave the system at the speed of light in any direction you want starting from a low speed. 

Second about the beacon, they knew very well the exact time dilation that miller´s planet have it before leave the endurance, but they only knew for certainty that the planet was a very bad idea after being 1 hour trap there, never would be a good home for the human race, due asteroids and different stuff trapped in the black hole field.

But in their perspective, you also need to take into account, that they thought that one of those 3 planets was the human salvation because an "alien race"  put a bridge for them there.

Also they were alone with all their decisions.. Because in earth they knew almost nothing about miller´s planet.

And yes.. I know what is frequency shift... but they receive the data from a sat relay they left close to the wormhole, when they cross the wormhole they receive all the data which was only "ok" messages. And it does not give more detail in that.  

But if you want better explanations, mines are just sentences from what I remember.  You will need to get the Kip Thorne´s Book and read it, there are 400 pages with all the movie physics and concepts explained with good detail.  He is an eminence in black holes, gravity waves and wormhomes. In fact the ligo experiment (now lisa) that now everybody is talking so much was designed by him.

The propulsion is fusion if I don't bad remember.

 

Also nobody should forget, that is the first movie with real visual about how it will look a wormhole and a black hole.. Just for that, everybody should be thankful..

The wormhole in Contact  movie was a disk :S  (also one of my favorite movies)

 

Edited December 7, 2015 by AngelLestat

[manaiaK]

On 7/12/2015, 8:20:17, Geher said:

If you liked the Martian then you'll probably also like Apollo 13.
https://xkcd.com/1536/

It is also very accurate regarding the science.

Thanks, Geher. I'll look for it.

[Frybert]

On 12/7/2015, 2:20:17, Geher said:

It is also very accurate regarding the science.

Probably because it actually happened. Unless of course you are one of THOSE people.

[SpaceXray]

On ‎12‎/‎1‎/‎2015‎ ‎7‎:‎03‎:‎59‎, SargeRho said:

The SSTO landers in Interstellar are the only thing I can actually think of, it required a booster rocket to put the Ranger into orbit the first time, but somehow they can land and take off from planets repeatedly.

Once again, SSTO fuel was expensive and scarce, much cheaper and practical  to launch 2 Rangers in 1 launch together with a supply pod on a chemical rocket.

[Temstar]

If you could make a SSTO like that you wouldn't make chemical rockets any more. It would be a bit like car makers hauling cars to the dealership using horses instead of trucks to save petrol.

[Geher]

9 hours ago, Temstar said:

If you could make a SSTO like that you wouldn't make chemical rockets any more. It would be a bit like car makers hauling cars to the dealership using horses instead of trucks to save petrol.

Unless cars are the fanciest kraken at that time and only here for the super rich.