Whether you actually agree with the science or not,
Interstellar is generally considered a masterpiece. A visual treat with truly
great acting and story. But that is not all Interstellar is. The visual
treatment of the blackhole isn’t made out of pure imagination, though the
depiction is unlike anything ever seen. The truth is it’s due to interstellar,
this visual form of Interstellar was discovered. The movie actually lended
itself in making of two research papers by Caltech physicist Kip Thorne one for
the astrophysicist community and one for the computer graphics community, who
worked as a scientific consultant for the film. I will divide this into two
parts – one explaining the science used in wormholes, and the other in the
blackhole.
I’ll explain the same beautiful and accurate science behind
the science of the blackhole Gargantua and the relative passage of time
depicted in the movie in the next part. Till then watch this space for other
great articles.
[Credits: Atul Aditya]
Let’s begin with the wormhole used in the movie for interstellar
travel. Before Interstellar, any and all movies depicted a wormhole as a flat
circular hole in space. But under the supervision on Kip Thorne, Christopher
Nolan sought to correct that. It has always been theorized that a wormhole is a
spherical hole in space-time. It is because the three dimensional universe of ours
is connected by extending a singularity on both sides through the fourth
dimensional space called bulk, thus any tear connecting two points in our
universe have to be a spherical hole. Let’s understand this by simple graphics,
of course it is impossible to represent a four dimensional space here so this
graphic would use a simple trick of collapsing a dimension like we do in our eg
sheets.
To understand how two singularities connect two points in
space time, we must first understand how a singularity works. According to
Einstein at a point in space, the presence of mass means presence of gravity.
Gravity effects the local space time of its surrounding region. So when
infinite density is present a point it extends the local space into the bulk,
as if it were made of rubber sheet giving it a cone like projection with the
tip being the singularity where the gravity and mass become infinite and time
almost doesn’t exist. Such infinite mass is achieved naturally in the universe
when a star collapses into itself where its mass gets concentrated in almost
negligible volume, giving it almost infinite density. Let’s understand this
now.
If the universal plane was considered folded, and the two
singularities were extended into each other, they will form a tunnel through
bulk and a shortcut through space time will be created and anyone in the plane
can fall through one opening of the tunnel to reach the other end quickly. So
this can be viewed as this.
Now we were understanding the model of a wormhole with one
dimension collapsed with our universe visualized as 2D plane, and the opening
mouth of the wormhole as a circular flat hole. But since the universe is actually
three-dimensional, the opening of the wormhole would also be three dimensional
and would be a spherical hole in the space. Exactly as depicted by
Interstellar.
For the computer graphics team behind Interstellar, this
proved to be a problem, to depict a spherical hole out of pure imagination, so
the visual effects supervisor of the Interstellar team asked for help from Kip
Thorne not wanting to compromise the accuracy of depiction of the phenomenon in
the film, who provided him with general equations which would help the team
trace behavior of light rays around a wormhole.
The first thing they made out was that light wouldn’t behave
classically around a wormhole, which is it won’t travel in a straight line. Any
of the rendering software available at the time wasn’t able to do so, so the
CGI team had to write a completely new renderer which would be able to do so
based on the equations provided by Thorne, and then rendered the wormhole. The
result turned out to be nothing like what anyone could visualize. The wormhole
was like a crystal ball reflecting the universe, a spherical hole in spacetime.
The reflection of space if the wormhole was viewed in person would be of the
space at the other end of the wormhole. This is the most accurate depiction of
wormhole ever and gave new insights into the phenomenon to Kip Thorne who
helped design it.
The wormhole depicted in the film is 2.5 miles in diameter
and connects two points in space nearly ten billion light years apart. The most
interesting part is that it accurately said to be placed there by someone, i.e.
it’s not a natural phenomenon because such a merger of two singularities in the
bulk is not possible without some external force which is in this case humans
from far future and this information is neatly integrated into the story.
Credits:
The Science
of Interstellar - Kip Thorne.
Wrinkles in
Space Time, The Warped astrophysics of Interstellar – Adam Rogers [Wired.com]
The Science
of ‘Interstellar’ Explained – [Space.com]
[Credits: Atul Aditya]
