[Fun Post] For Enterprise App Developers on the Moon: Does the iPad’s accelerator work in space?

June 8, 2013

This was a question asked on Reddit, and who knows who you next client is, so a goo read:

Natty Dred (On Reddit): “Could they theoretically be able to change the orientation of the device and have it function just the way it does on Earth?”

No.

The ISS is in constant free fall. That means, due to gravitational acceleration, the ISS keeps falling towards the center of earth, but due to its considerable tangential velocity it keeps “missing” it.

Since it is in free fall, there is no “proper” force acting on it. (Remember, that according to general relativity, gravitational attraction is not a force, but rather a result of spacetime itself being bent)

Since there is no proper force acting on the ISS, the iPad has no way of knowing which way it is held.

Another more formal response:

CaffeinatedGuy: Correction: you are referring to the gyroscope. OP is talking g about the gyroscope. Everyone here is calling for the gyroscope an accelerometer.

This is /r/askscience. Please use correct terminology.

Accelerometers measure change in force (like acceleration) and would in fact work properly in space. Say he had a fishing app and it used the accelerometer for casting. That would work (though the gyroscope wouldn’t be able to detect position, so casting still wouldn’t work). http://en.wikipedia.org/wiki/Accelerometer

Gyroscopes measure orientation relative to an xyz axis. While it’s theoretically possible that it would work in space, the orientation is relative to gravity in this case and would not work in space (on the ISS).http://en.wikipedia.org/wiki/Gyroscope

Therefor, the accelerometer would in fact work in space, but the question is incorrectly referring to the gyroscope, which would not work.