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I know that the science in movies is questionable and sometimes ridiculous but I would think this question would have been more obvious to the script writers. When they visited Miller's planet they were almost killed by a re-occurring tidal wave. In a few short minutes they ended up spending 23 years there. When they were still orbiting the planet before going down wouldn't they have seen multiple tidal waves occurring one after another? Therefore why even bother landing on the planet?

Qmechanic
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Bill Alsept
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    Might [movies.se] be better suited for this question about the script? – Kyle Kanos Nov 25 '15 at 21:47
  • If my observation is obviously correct to everyone then maybe it could be in the movie/TV category? But I was kind of asking is this correct? Therefore it is a physics question. – Bill Alsept Nov 25 '15 at 21:52
  • Kyle, you voted me down without even answering my Physics questions. Wouldn't they have seen multiple tidal waves occurring one after another? Therefore why even bother landing on the planet? – Bill Alsept Nov 25 '15 at 22:08
  • Therefore why even bother landing on the planet is a question for the screenwriters of the film, *not* physicists. – Kyle Kanos Nov 25 '15 at 22:21
  • Kyle, my question "wouldn't they have seen multiple tidal waves occurring? " is a decent physics question. Why not answer the question instead of playing these word games? – Bill Alsept Nov 25 '15 at 22:32
  • There's a lot wrong with Interstellar. It was portrayed as being scientifically accurate, but google on Interstellar pseudoscience. What particularly irritated me was the notion that quantum gravity would permit time travel. It's bunk. – John Duffield Nov 25 '15 at 22:37
  • @JohnDuffield: IIRC, the buffing it as scientifically accurate was with respect to the depiction of black holes & time dilation, not with all the science of the film (e.g., the mysterious crop deaths). – Kyle Kanos Nov 25 '15 at 22:38
  • @BillAlsept: perhaps asking about seeing the tidal waves would be an okay question, but asking about why they landed is most certainly not a physics question. – Kyle Kanos Nov 25 '15 at 22:39
  • @KyleKanos : I take no issue with time dilation, but the black hole depiction was debateable, the wormhole was pure science fiction, ditto for the time travel, and as for the bulk, well. Don't get me wrong, I like science fiction movies, even when I know the science is a fantasy. But I object to the science being billed as bona-fide when it isn't. – John Duffield Nov 25 '15 at 22:46
  • OK guys we all know the science in the movie was ridiculous but back to my question. I'm interested in what a person orbiting Miller's planet would have observed. Would there have been multiple tidal waves, possibly even thousands observed just looking down at the planet because of the time dilations? – Bill Alsept Nov 25 '15 at 22:55
  • Let me add my two pennies worth saying that time dilation is much more complicated than it was depicted. It depends on the (space-time) path to be integrated on and may be unrelated to the actual biological time that organisms live by; therefore saying that staying on a planet or travelling within this particular gravitational field ages you more or less than expected is imprecise. – gented Nov 25 '15 at 23:52
  • I hope everyone doesn't mind me posting a link to Kip Thorne's book.. http://m.space.com/28075-science-of-interstellar-book-review.html – Declan Nov 26 '15 at 03:26

4 Answers4

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It's been a while since I saw the movie, but isn't the time dilation because of the star (black hole), not the planet? If so, the same time dilation would have been in effect whether in orbit or on the surface of the planet.

Benito Ciaro
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  • That is kind of what I thought. There would not have even been a 23 year difference. – Bill Alsept Nov 25 '15 at 23:56
  • depends on the gravity gradient from orbit to planet's surface. But I believe the point was this black hole was so supermassive that the tidal forces/gradient would not be that large - so that it would not rip apart the space vehicle and its occupants. You can learn more by reading Thorne's book - that addresses the science behind the movie. – docscience Nov 26 '15 at 00:23
  • ... and maybe the vehicle's sensors were unable to resolve wave height from that altitude. Even though huge. – docscience Nov 26 '15 at 00:25
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    Were they orbiting the planet? I thought the main ship was in some much more distant orbit around the hole, and they just sent a lander or something to the actual planet. – AGML Nov 28 '15 at 19:18
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A few minutes on the planet (meaning, deeper in the gravitational well of the black hole) corresponds to a couple decades where the ship is orbiting. Thus in the couple decades the ship is waiting, it only sees the one passage of the wave.

This is akin to the popular science depiction of an astronaut falling into a black hole. To an observer keeping a safe distance, the infalling astronaut appears to slow down. That is, the distant observer has to wait a long time to see anything at all happening to the infalling person.

Another way to look at this is to use a spacetime diagram. My extraordinarily rough but qualitatively correct attempt is below. Time flows up; the planet and black hole are somewhere off to the left. The left branch is the worldline of the crew that goes to the surface, while the right branch is the path taken by the ship staying in orbit. $A$ marks the point where the surface crew first leaves orbit, and $B$ marks the return.

spacetime diagram

Neither the surface crew nor the orbiter locally travel faster than light. This translates into their paths being more steep than $45^\circ$ in the diagram. Light moves at $45^\circ$ lines. As a result, any light signal either misses both paths or intersects them both exactly once. Even though traveling the left path you experience a few minutes between $A$ and $B$, whereas you experience years between the same points along the right path, you will see the same number of waves pass a given point on the planet over that time. Decades in orbit gets you the same amount of information as a few minutes on the planet.

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I know that the science in movies is questionable and sometimes ridiculous but I would think this question would have been more obvious to the script writers.

Quite. Have a look at InterstellarWiki and note this: "Miller is a water world and the first planet in the system orbiting Gargantua. Miller takes its name from Dr. Miller, who landed on the planet and activated the "thumbs up" beacon".

When they visited Miller's planet they were almost killed by a re-occurring tidal wave.

Yes, and note this: "10 years before the Endurance crew travelled through the wormhole, NASA sent twelve landing pods through it, each carrying a scientist to assess a potentially habitable world. Miller was selected to land on this world. However, within a relative hour after her arrival, she encountered one of the massive tidal waves circling the planet. She was unable to negotiate the encounter and her landing pod was destroyed. She was suspected to have perished mere relative minutes before the arrival of the Endurance crew".

So, you find a planet, there's no land, but you give it the thumbs up inside an hour? It isn't just the science that's flaky in this movie. The plot is flaky too.

In a few short minutes they ended up spending 23 years there. When they were still orbiting the planet before going down wouldn't they have seen multiple tidal waves occurring one after another?

Yes. Because "Miller is a water world, covered in a seemingly endless, shallow ocean". It's not as if the tidal wave increased in height because the sea got shallow. They would have seen that 4000ft tidal wave. And they would have certainly detected it on radar. Regardless of time dilation.

Therefore why even bother landing on the planet?

Because it's a movie. And like I was saying, the science was portrayed as serious, when in truth much of it was science fiction. See this which backs up what Benito said:

"Being well within the tremendous gravitational field of Gargantua, time on the surface of Miller's planet passes very slowly relative to the rest of the universe".

If you were going to land on a planet, you'd orbit it and check it out first. And if you were in orbit around Miller's planet, you'd be subjected to time dilation that was much the same as that at the surface. The time dilation for GPS satellites is miniscule, it's 38 microseconds a day.

John Duffield
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  • Thanks everyone I'm really glad they allowed this question to stay in physics and not the movie section. I realize now planet and star would have been in the same gravity well or the same time dilation. On the other hand if there really were a 23 year difference in time dilations then my original question would have applied. – Bill Alsept Nov 28 '15 at 19:02
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In addition to what should be a miniscule difference in time dilation between the water planet's orbit and the water planet's surface, I still don't understand the tiny difference in subjective time separating the two landers' arriving on the water planet's surface.

If two identical ships start a journey in the same frame of reference, and then travel identical paths that end up in the same frame of reference, then the subjective difference in time separating the two ships should remain constant.

For instance, in an automobile race two cars may go faster in some parts of the track and slower in others, but the difference in departure/arrival times should always remains the same. If Car B starts the race 5 minutes after Car A, then Car B should also finish the race 5 minutes after Car A, no matter how twisty the track. Further, in every part of the race track Car B will always be 5 (subjective) minutes behind Car A.

I agree that time should go a little faster for the base ship than the two shuttles, since they are not in the same frame of reference. (Assuming the base ship is orbiting the planet which I am not sure on.)

posfan12
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