My question has to do with gravitational time dilation.

What would really happen to a human in a temporal frame where time slowed down (as it did on the water planet in Interstellar, where 1 hour on the water planet = 7 earth years), and what would an observer outside of that dilated reference frame actually observe if he could see into it or measure something in it (i.e., if Romilly had a powerful telescope and could look down from the Endeavor and see Cooper and Brand, or if he could monitor their heartbeats from orbit)?

(1) Would he see Brand and Cooper moving in slow motion … incredibly slow motion … so, for example, if Cooper moves his arm, let's say, 12 inches, in a matter of a milliseconds in his frame, would Romilly see that event play out over a very long period of time (i.e. days or weeks) in his frame?

(2) In Cooper/Brand’s time frame, their hearts are beating at 60 beats per minute … but if Romilly were able to monitor their heartbeats from his frame, would it appear to him that their hearts were beating once every 17 hours … and if so, how could they possibly survive? I am perplexed!

  • You might want to take a look at the Stargate SG-1 episode "A Matter Of Time". It's not with a telescope (which wouldn't work due to red-shifting) but with video instead. They have to deal with the relativistic effects on a video transmission going through a wormhole near a black hole. – PointlessSpike Nov 14 '14 at 10:26
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    Your second point regarding "how could they survive their heart beat being so slow" suggests you're still thinking of a "Real time". There is no such thing. The person on the planet could equally say "the person on that ships heart is beating at a billion times a second, how can they survive? In reality both hearts are beating normally in their local time frame and that's all that matters – user20310 Dec 3 '14 at 22:13

If one tried to view a scene from a 'time dilated' location, several problems would arise. First there's the 'red shift' phenomenon, which would push the visible light of the location far into the infrared for the viewer, in this example. Next, there would be distortion in objects and reflected light that would seriously alter the appearance of the viewed location.

Other impediments exist, but these are enough to make it hard to even view from one location to the other. If, somehow, you could interpret the data and actually 'see' the slowed location, it would appear to be stopped, at first glance, and then gradually you might perceive a change in the environment that allowed you to realize it was actually moving, but very, very slowly. Think of the protagonist in Clockstoppers where they were moving so quickly that the world around them seemed to have stopped.

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    Hi and welcome to StackExchange! It's been a while since I studied relativity but AFAIK this is correct. The "red shift" effect is important -- light returning from the time-dilated location would increase in wavelength, becoming infrared or even microwaves/radio waves for an external observer. To the naked eye, the "time-dilated" location would seem to be covered in darkness. – Royal Canadian Bandit Nov 9 '14 at 20:47
  • Could x-rays or gamma rays emitted from the time-dilated location get shifted into visible light wavelengths then? – matts Nov 12 '14 at 21:30
  • @matts -- Yes. AIUI this could be happening with the accretion disk -- matter falling into the black hole emits highly energetic gamma rays, which are red-shifted to visible light for a more distant observer. – Royal Canadian Bandit Nov 13 '14 at 9:31

It's hard to say what data coming from a time dilation field would be like when viewed in real time, but it's most likely that the receiving station would run into a buffering error since one minute of data would encompass 17 hours (in the movie example) of time.

As far as the surviving the time dilation field, when they are in it time passes normally for them but, outside, time accelerates in their frame of reference. So, yes, outside the field their heart beats once every 17 hours but in it it's 60 beats per minute.

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