I don't know whether anybody mentioned that, but I found this little uncertainty in a scene:

After they cross the wormhole near the Saturn and arrive to the other side, they start a discussion where to go first of all. And in this scene there is a super short cut(like 2-3seconds, around 1hour:2minutes) in which we see Dr. Brand sitting near a window, and in the window we clearly see that the picture is moving from top to bottom, in a circular motion, which center is in the left side of the screen.

enter image description here

And here comes the question: if the Endurance rotates for creating artificial gravity, then shouldn't be the floor perpendicular to the radius of rotating circle?

They now sit parallel to the rotating circles radius.

Here is another picture that explains what I would expect

enter image description here

Its a cut mistake, or alright with this scene?

  • 1
    Centripetal force would act in the direction opposite of the arrow in your image. Right now it's showing centrifugal force. Aug 22, 2017 at 21:11
  • 1
    I see where you are getting at - it looks like a mistake. From that image it looks as if the centre of rotation is somewhere to the left of Brand behind the monitors, where as the star field would more or less pan up past the window if this view was actually from one of the modules. Aug 23, 2017 at 2:27
  • I meant, that the centripetal force that holds them on the floor, acts at THAT point. Sorry for forced explanation. Aug 23, 2017 at 17:53

1 Answer 1


You're right.

The point of spinning for artificial gravity is to use a perceived centrifugal force. The people would then be exactly between the floor and the axis of rotation.
This means that the axis of rotation would need to be "top center" in the image you linked, not to the left of Anne Hathaway (edit assuming they are located in the outer ring of the ship)

As was mentioned in the comment, your image denotes centrifugal (Latin: "fleeing from the center") force, not centripetal force (Latin: "pulled towards the center").
Centrifugal force is not a real force. It is the resulting output when you combine two different forces (that do exist):

  • Centripetal force, i.e. when a discus thrower is swinging the discus, his arm pulls the discus towards the thrower
  • Linear momentum, i.e. when a discus thrower releases the discus, it travels in a straight line.

Centrifugal force is nothing more than a perceived force, the result of these two listed forces, as seen from the frame of reference of someone who is rotating (which is the frame of reference that the camera shot in your question shows).

i.e. If you ask the discus what's going on when the thrower is swinging it around, the discus will tell you that it feels like it's getting pushed away from the thrower.

Your image is wrong, but the idea behind your question is right.

Pedantry and ways the movie could be argued to be somewhat correct (when you don't look at the details)

1. They could be in the "cockpit" in your image.

Looking at the rotation in the gif, the center of rotation seams to be really close to what we can see. From my guesstimate, the center of rotation is roughly in the center of the image when the gif ends.

That means that technically speaking, Anne Hathaway is still positioned between the floor and the center of rotation, but she must be really close to the center of rotation (and therefore the center of the ship). This is probably a mistake, as I assume that the people are located in the outer ring, which is notably further from the center of rotation than this image shows.
However, if they are currently inside the "cockpit" (the inner chamber of the ring in your image), then this could actually be correct. You'd expect the simulated gravity to be less strong (compared to the outer ring), but still present.

2. Gravity could be simulated by acceleration rather than rotation

Looking again at the gif you linked, let's assume that the ship was stationary (not spinning), and then started to spin. This acceleration would simulate a gravitational pull, for as long as the ship keeps accelerating (= increasing the rotational speed).

Earth analogy: You're in a drag race. The lights turn green and you put the pedal to the metal. You get pulled into your seat due to the acceleration (= simulated gravity). Once you hit 150mph, you decide to stop accelerating and instead cruise at a steady 150mph. While cruising, you are not pulled into your seat because there is no acceleration anymore. You only feel like you're being pulled into the seat for as long as your travel speed increases.

Anne Hathaway's perceived simulated gravity, and the direction of rotation (assuming that it is accelerating) correspond with eachother. If you assume that the ship's rotation was accelerating at the time of this camera shot, then Anne would indeed be pulled towards the floor (similar to gravity).

However, for this to be used as the method for simulating gravity, that means the ship would continuously have to accelerate. Not only is that wasteful for fuel resources, it would also end up spinning at a massive speed (depending on the timespan, at least hundreds or thousands of RPMs).

This means you would run into structural issues, the ship tearing itself apart. The people in the outer ring would then also be experiencing an incredibly strong simulated gravity, many times more than that of Earth.

So this isn't possible on the long term. But if I'm being pedantic, and we assume that the people were in the cockpit, and the ship was only starting its gravity simulation (thus still accelerating), this scene could be somewhat plausible.

But again, you're most likely right

The pedantic points I bring up here are not meant to refute your claim. My intention was rather to showcase that the movie's creators could have thought that they were doing the right thing. Both of my pedantic arguments sound like they are viable at first, but they fall apart once you start to apply the theory in more detail.

So this could be a case of half-assed science, rather than just being blatantly wrong from the get-go (no-assed science, I guess). That should at least somewhat redeem the creators. But they've still made a mistake.


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