NOLAN: The initial impetus for the project had been to say:
"Why not examine real possibilities.
Where are we now ? Where has the world got to...
...in terms of its thinking about gravity being able to traverse dimensions...
...gravitational lensing ? Effects of gravity and light around a black hole.
Why not actually look at the real science there ?"
JONATHAN: Luckily we had Kip.
And Kip is the foremost authority on all-things gravitational.
The warping of space inside here scatters some of it back...
...light scattering off of the surface of a rippled ocean.
I started talking to him and about three sentences in...
...he'd lost me. Ha-ha-ha.
He came in on the set with me and was writing out all my stuff.
I couldn't do it. Ha-ha.
And when you see the theory...
...you go, "How the hell ?
What is it ?" You wonder, "What sort of mind do they have ?"
Wormholes nor black holes...
...have been depicted in any Hollywood movie in the way that they actually would appear.
This the first time the depiction began with Einstein's general relativity equations.
The idea that space is warped and time is warped...
...and that those give rise to gravity.
Those cause time to flow more slowly in some places and more rapidly in others...
...and conceivably, possibly, maybe we can go backward in time...
...these are fabulous ideas.
I think there are all kinds of different sets of surprises...
...when you start really, you know, digging into what the science can do.
A lot more on my part than his part, I think.
I mean, there are certain breakthroughs you make creatively...
...even just understanding or asking Kip:
"Okay, well, this wormhole you're describing, it's a spherical object.
It's not a circular object."
And to him that is incredibly obvious.
For the rest of us, that's actually a very radical notion...
...the idea of a spherical hole.
THORNE: I really like to go back to the way the Wormhole got its name.
If you have a nice bright red apple with a Wormhole through it...
...and you imagine that you, yourself, are an ant...
...the surface of the apple is your universe.
You want to get from the top of the apple down to the bottom on the other side.
You have a choice of walking around on the surface of the apple...
...or walking through the Wormhole.
When you go through the wormhole, you're walking on the side of the Wormhole.
The side of the wormhole is part of your space.
The interior of the Wormhole is not.
It's part of the higher dimension.
When you go through this opening, this mouth...
...you find yourself in a sort of a tunnel...
...that leads you through this higher dimension...
...to another location in our universe where there is another mouth.
What is a hole if it's in three-dimensional space ?
And a three dimensional hole is a sphere...
...and that essentially is what the exterior of the wormhole looks like.
What makes it rather more exotic is that because you are actually warping space...
...what you're actually doing is creating a gravitational effect.
And so when light shines through this, it gets refracted in the same way...
...that the light in this room is being refracted by the glass in your spectacles.
We could make our fantasy version of this thing and say, okay, well, I know what it looks like.
Big glass ball in space with some warpy space around it.
But we wanted to be a bit more rigorous than that.
And so we had to work out how to calculate all the paths that the lights rays would take...
...through this warped space around the wormhole.
The challenge has always been as to whether wormholes...
...can really exist in the real universe.
Can they exist ?
Second question, if they can exist, can they exist naturally ?
If something like a wormhole appeared by its very appearance you would know...
...that we were engaging with some other type of intelligence.
There's no such thing as a naturally-occurring Wormhole.
It's very hard to imagine with the set of rules in this universe being what they are...
...that such a thing would occur.
So you know if there is a wormhole there that means someone had to put it there.
So from a dramatic perspective it was a very exciting point to embark from.
FRANKLIN: Black holes have been represented in movies in the past...
...and it tends to be a literal interpretation.
It just literally looks like a giant drain in space with everything swirling down it.
Kip explained to me at the outset, that is not an accurate representation of a black hole.
THORNE: A black hole is a thing with such intense gravity...
...that it won't let any light or signals of any sort come out.
This thing, this object, has a surface, which is--
ls just the location beyond which nothing can come out.
That surface is called its horizon.
If the black hole is not spinning, the horizon is spherical.
Round, like the Earth.
If it's spinning, then it drags space into motion, like the whirling air in a tornado.
And that motion is so powerful...
...that if you go down near the black hole, no matter how hard you blast your ship...
...you can't prevent yourself from being whirled around...
...like a straw in a tornado.
You also have warping of time.
If you go down very near the surface of the black hole...
...the rate of flow of time that you experience is much slower than faraway.
So that if you were hovering near the black hole for a day and return...
...many years or centuries could have elapsed on Earth.
So time is highly warped.
Inside the black hole, time flows toward the center.
That's really why nothing can come out...
...because nothing can move backward against the flow of time.
The future flow of time inside the black hole drags with itself everything toward the center.
At the center, there is a singularity.
A place where space becomes infinitely warped.
A place where we don't know what happens after that.
It's a place where the laws of physics as we know them fail.
I think that when you venture out into a story about a journey...
...into a story about man against the elements...
...when that journey is interstellar...
...when that journey allows you to go, you know, beyond our actual galaxy...
...the possibilities for visualizing threat...
...against our protagonist become very much more exotic.
And Kip has the formula.
He has the potential to calculate the way a black hole would look, for example...
...with the current scientific understanding...
...of the gravitational lensing that would occur and so forth.
But he actually doesn't have the computing power in graphics capability.
THOMAS: The visual effects department under Paul Franklin...
...and everybody at Double Negative took Kip's mathematical data...
...and they created real visual representations of what a black hole is meant to look like.
FRANKLIN: The collaboration has produced...
...visualization of things nobody'd managed to do before.
We potentially may have discovered a couple of new things...
...that were lurking there inside the mathematics, inside the physics.
THORNE: I worked out the equations...
...that would enable him to do the gravitational lensing.
So you have light that comes from a star behind the black hole.
It may come in, go around the black hole several times...
...and then cut to the camera.
And so you wind up with several different images of the star.
FRANKLIN: The black hole warps the space so much.
It just looks like you're looking at a strange sort of funnel in the sky...
...with this intensely black circle at the middle of it.
But the gravity of the black hole draws in all the matter from the surrounding universe.
And this spins out into a giant disc around the central sphere...
...and as it whirls in towards the center, the gas gets hotter and hotter.
And this thing, the accretion disk around it shines brilliantly.
And then we found that if you then render this whole thing...
...you visualize it all through this extraordinary gravitational lens...
...the gravity twists this glowing disc of gas into weird shapes...
...and you get this extraordinary sort of rainbow of fire across at the top of the black hole.
And I saw this disc wrap up over the black hole and under the black hole.
I had known it intellectually.
But knowing it intellectually is completely different than seeing it...
...than feeling it.
NOLAN: We had determined when we started down this road...
...that if it didn't looked like something that'd be comprehensible to the audience...
...we would have to manipulate it in some way.
But what we found was...
...as long as we didn't change the point of view too much of the camera position...
...we could get some very understandable tactile imagery from those equations.
They were constantly surprising.
It spoke to the maxim that, you know, truth can be stranger than fiction.
Another thing that we were very interested in was the idea of creating environments...
...particularly the space environments live on the stage.
NOLAN: What we started talking about was, well, could we get the imagery...
...advanced enough that we would have views that we could put outside the windows...
...that would hold up to be, you know, out of focus, you know, background shots.
What we realized was that digital projectors had got to a point...
...where the images were bright enough to be usable for this kind of front projection.
The great thing with the digital projector is that...
...you can put a lot more content onto it very, very quickly.
The big challenge with that though, of course...
...is it meant that a lot of our creative work had to start very, very early on.
And we had to start producing more or less finished images...
...that we could use in this projection process on the set.
It was a huge effort in terms of utilizing current projection technology...
...in a way that hasn't been done before. The long and the short of it being...
...rather than trying to project a huge backdrop that you could shoot from any angle...
...we would use one or two projectors...
...to just align with the camera point of view...
...and keystone correct and correct the distortion...
...appropriate to where a camera was looking from.
We found that by doing this...
...we could actually get the images bright enough...
...that we could still light the set in the normal way...
...and what was outside the window would expose and look pretty natural.
As we got more and more confident...
...we got more and more happy...
...with this business of continually moving the projectors around.
We wanted something that was very flexible. We didn't want to pre-assume our angles...
...because we had a projection screen.
With those instruments that we had, we figured, oh, we can actually be flexible.
We can move those projectors around every time when we have a view...
...we can sort of add another layer behind it with projection.
One thing they discovered was that if Paul took that content on a different projector...
...and projected that content onto the actors in the cockpit...
...there'd be interactive lighting with the background.
So for instance, one of the scenes where Matthew's inside the Ranger...
...Cooper is penetrating the event horizon of the black hole flying down inside it.
We had this spectacular light show projected on the screens outside.
We had another set of projectors pointing directly in through the window...
...projecting the same image onto him.
And what that gave you is what we call a synchronized lighting gag.
As the content was changing outside on the window...
...so was the light that was actually on Cooper.
HOYTEMA: Because of the Imax, it could easily work with very low light levels.
We certainly got a huge renderment out of those projectors as well.
So, you know, certainly gave sort of a new life into what front projection could be.
HATHAWAY: All of it just allowed you to really lose yourself in it a bit more...
...and be able to turn off that little voice inside your head...
...that sometimes shows up when you're doing green screen...
...when you think, "Am I doing this right ? Do I look foolish ? Am I on the same page ?"
You know what you're looking at...
...because everybody is looking at the same awesome wormhole.
[HATHAWAY CHUCKLES]
Which was incredible.
I had an emotional reaction to seeing it, it was so beautiful.
It was like looking at a great piece of art.
And the first time that we all looked at the spin for real...
...when they're projecting the spin outside of us, we all really did get motion sickness.
Instead of visual effects being an afterthought...
...that happens in the post production process after the movie's wrapped...
...it was very much part of the heart of the whole filmmaking process right from day one.
And that was really quite unique for me.
I'd never worked that way.
And certainly never worked quite as hard on set as I did on this film I think.
THORNE: We're going to write several technical papers about this.
One aimed at the astrophysics community.
And then something for the computer graphics community...
...saying, "Here are some things that we've discovered about gravitational lensing...
...by rapidly spinning black holes that we never knew before."
So this collaboration isn't over...
...until we've given some sense of the things that we've learned.