Looking down at different times

[Xylotile]

Most of you are familiar with the movie Interstellar ft. Matthew McConaughey. The scene I would like to discuss is when Romilly (David Gyasi) waited in the ship while the other members flew down to the planet to observe it. When the crew came back to the ship they were gone for what seemed a couple of hours, but for Romilly they were gone for 23 years. This is a big if, but what would Romilly see if he could spot the crew members from below. Would they be moving slower since time is different in the ship and on the planet? I'm not sure I posted this in the correct section, but I couldn't find anywhere else to put it.

[Silvestru]

Of course Interstellar is just a movie so it is not scientifically accurate in all points. In your example I came up with 3 points:

 

1) Gravitational time dilation is real but for 2 hours on the planet/23 years for Romilly an object would have to be so close to a black hole that it would inevitably spiral into it.

 

2) The other problem is that the crew could not survive such high Gravity on this planet. (No matter how fit McConaughey is)

 

3) And the third that I can think of that even if they could, there is no chance that they could leave this planet. For a place with such a bit gravitational time dilation, you would need an escape velocity (How fast you have to go in order to escape the gravitational pull of a body) of almost the speed of light.

 

To try to answer your Question, Romilly would see the planet, her spaceship and all the past decisions that she made which led her to this place, get sucked into this super-massive black hole.

Edited June 14, 2017 by Silvestru

[swansont]

Of course Interstellar is just a movie so it is not scientifically accurate in all points. In your example I came up with 3 points:

 

1) Gravitational time dilation is real but for 2 hours on the planet/23 years for Romilly an object would have to be so close to a black hole that it would inevitably spiral into it.

 

2) The other problem is that the crew could not survive such high Gravity on this planet. (No matter how fit McConaughey is)

 

3) And the third that I can think of that even if they could, there is no chance that they could leave this planet. For a place with such a bit gravitational time dilation, you would need an escape velocity (How fast you have to go in order to escape the gravitational pull of a body) of almost the speed of light.

 

To try to answer your Question, Romilly would see the planet, her spaceship and all the past decisions that she made which led her to this place, get sucked into this super-massive black hole.

 

 

Romilly is the one far away from the black hole, and the time dilation is not a function of the strength of gravity changing, it's dependent on the location within a potential well. Since this is a supermassive black hole, gravity can be fairly weak even close to the event horizon. Without running any numbers, one can't validly draw such conclusions.

[Silvestru]

Since this is a supermassive black hole, gravity can be fairly weak even close to the event horizon. Without running any numbers, one can't validly draw such conclusions.

 

Sorry Swansont, I don't really understand what do you mean by the gravity is fairly weak close to the event horizon.

 

You are saying that it is a possible scenario for a planet to have such a time dilation without being on the verge of getting sucked in a BH?

[swansont]

 

Sorry Swansont, I don't really understand what do you mean by the gravity is fairly weak close to the event horizon.

 

You are saying that it is a possible scenario for a planet to have such a time dilation without being on the verge of getting sucked in a BH?

 

 

Sorry, that should have been "gravity gradient". The people in orbit are in freefall. Why would the value of the BH gravity matter for survival on the planet?

 

To get the answer, you need to do a proper analysis. You have not presented one, so it's impossible to draw the conclusions you did.

[Silvestru]

I was surprised to find that the planet name is Miller and it has it's own page.

 

http://interstellarfilm.wikia.com/wiki/Miller_(planet)

 

Also on this page there are Speculations like the one below:

The time dilation on Miller due to the gravitational forces of Gargantua would be tantamount to the planet moving at roughly 99.99999998% the speed of light.

 

I also found the post below relating to the same Miller planet.

 

 

Of course these are not my calculations, I am not taking credit for them or anything.

Please tell me if this analysis holds up.

Also if you want the explination for this quote:

 

The time dilation on Miller due to the gravitational forces of Gargantua would be tantamount to the planet moving at roughly 99.99999998% the speed of light.

 

and basically all the questions in the OP please read:

 

https://www.space.com/28077-science-of-interstellar-book-excerpt.html

All in all, Kip Thorne tries to make a scientific explination for the possibility of this planet to actually exist but of course he had his agenda.

 

(my opinion) Of course a planet that satisfies all these conditions cannot exist.

[swansont]

I was surprised to find that the planet name is Miller and it has it's own page.

 

http://interstellarfilm.wikia.com/wiki/Miller_(planet)

 

Also on this page there are Speculations like the one below:

 

I also found the post below relating to the same Miller planet.

 

 

Of course these are not my calculations, I am not taking credit for them or anything.

Please tell me if this analysis holds up.

Also if you want the explination for this quote:

 

 

and basically all the questions in the OP please read:

 

https://www.space.com/28077-science-of-interstellar-book-excerpt.html

All in all, Kip Thorne tries to make a scientific explination for the possibility of this planet to actually exist but of course he had his agenda.

 

(my opinion) Of course a planet that satisfies all these conditions cannot exist.

 

 

Thanks, that's the kind of thing I wanted to see. Science.

[Janus]

I was surprised to find that the planet name is Miller and it has it's own page.

 

http://interstellarfilm.wikia.com/wiki/Miller_(planet)

 

Also on this page there are Speculations like the one below:

 

I also found the post below relating to the same Miller planet.

 

 

Of course these are not my calculations, I am not taking credit for them or anything.

 

 

 

Please tell me if this analysis holds up.

I'm not sure where the the value for the minimum radius for a stable orbit comes from, as from my understanding its lower boundary is at the photon sphere at

[math] r = \frac{3GM}{c^2}[/math]

or 3/2 that of the Schwarzschild radius.

The gravitational time dilation at this distance is

[math]t = t` \sqrt{1-2/3} = ~0.577[/math]

However, this is not the only factor that determines the clock rate as measured by a distant observer. The clock in question is orbiting the BH and time dilation due to its orbital speed must also be taken into account.

 

When you do so, the time dilation for a clock in orbit at a distance of r becomes:

 

[math]t= t`\sqrt{1-3r_s/2r}[/math]

Where r_s is the Schwarzschild radius.

 

If you substitute the photon sphere radius for r, you get

[math]t= t` \sqrt{1-1} = 0[/math]

 

So essentially this means that as the orbit size decreases towards the photon sphere, the total time dilation factor approaches infinity.

 

As far as escape velocity goes: While it is true that the escape velocity from that close in to the photon sphere is large, you would not have to supply all of it. Since the planet you are sitting on is in orbit around the BH, it is already traveling at ~71% of escape velocity for its distance. You would just need to provide the remaining 29% ( not to say that this would not be a feat in of itself).