The Science of Interstellar: Tidal Wave

[DaveC426913]

One of the nitpicks about Interstellar the film is the tidal wave on Miller's Planet. Miller's Planet is deep in the gravity well of a monster black hole.

Lot's to unpack there but the upshot is that there's a tidal wave that sweeps around the planet shaped like a tall, very steep mountain (ostensibly 4,000 feeet tall, if the infographic is to be trusted):

The nitpick is that this should not be so. The black hole's effect on the ocean planet should be distributed across the planet's surface, like this:

Critics of the science of movie have drawn attention to this "flaw".


But in a conversation today I suddenly realized that it doesn't have to be that way. That idealized sweep of the tidal bulges in that example diagram assume an ocean deep enough that bottom friction plays no part in the surface behavior.

But we know that Miller's Planet does not have miles deep oceans - they're standing in two feet of water. What I say we're seeing here is a wave much like any wave approaching a beach on Earth - a state of almost cresting and breaking.

In Miller's Planet's case, the tide is sweeping around the planet under the pull of the BH and I say it just happens to be the right depth that fricton with the bottom is slowing it down enough to keep it on the verge of breaking. (We have no reason to believe the wave is perpetually in this state - for all we know, it broke immediately beyond the landing site in the story.)

No?

 

[pinball1970]

One of the nitpicks about Interstellar the film is the tidal wave on Miller's Planet. Miller's Planet is deep in the gravity well of a monster black hole.

Lot's to unpack there but the upshot is that there's a tidal wave that sweeps around the planet shaped like a tall, very steep mountain (ostensibly 4,000 feeet tall, if the infographic is to be trusted):

View attachment 352198
View attachment 352200

The nitpick is that this should not be so. The black hole's effect on the ocean planet should be distributed across the planet's surface, like this:

View attachment 352199

Critics of the science of movie have drawn attention to this "flaw".


But in a conversation today I suddenly realized that it doesn't have to be that way. That idealized sweep of the tidal bulges in that example diagram assume an ocean deep enough that bottom friction plays no part in the surface behavior.

But we know that Miller's Planet does not have miles deep oceans - they're standing in two feet of water. What I say we're seeing here is a wave much like any wave approaching a beach on Earth - a state of almost cresting and breaking.

In Miller's Planet's case, the tide is sweeping around the planet under the pull of the BH and I say it just happens to be the right depth that fricton with the bottom is slowing it down enough to keep it on the verge of breaking. (We have no reason to believe the wave is perpetually in this state - for all we know, it broke immediately beyond the landing site in the story.)
View attachment 352201

No?

Kip Thorne put a book out, it's referenced on pf

The wave is mentioned by #10 in the pf thread

"Interstellar: A Visual Masterpiece with Disappointing Writing and Physics."​

 

[DaveC426913]

Kip Thorne put a book out, it's referenced on pf

Yes. It's been too long since I read it to remember.

 

[DaveC426913]

Right. Miller's Planet would be tidally locked.

The very process that creates the giant wave I speak of is friction. Plenty enough to grind the planet's rotation to a halt.

There would still be a crest of water, but it would be stationary.

Thanks everybody. Great discussion.

 

[pinball1970]

Thanks everybody. Great discussion

I think they all did it in 2014 Dave.

 

[snorkack]

Right. Miller's Planet would be tidally locked.

The very process that creates the giant wave I speak of is friction. Plenty enough to grind the planet's rotation to a halt.

There would still be a crest of water, but it would be stationary.

Thanks everybody. Great discussion.

Just because it is tidally locked does not, in itself, eliminate tides. You also have to get rid of eccentricity.
I assume that friction somehow works against eccentricity, too, but how? When a tidally locked, eccentric body loses eccentricity to tidal friction, what becomes of angular momentum and orbital energy?