Recently released ‘Interstellar’ film created more enthusiasm
and expectation among the science fiction film lovers. Film subject deals with
the search of a habitual planet in nearby galaxy after earth became inhospitable
for life. This film has been aptly released at a time when kepler mission (which
is associated with finding habitual planets in nearby galaxies) is giving
encouraging results. Though the film script is weak, still the movie is interesting
with many realistic scientific concepts like black holes, worm holes, time
dilation. Any unfamiliarity with many of the scientific terms in the movie will
lead viewers to get feel lost in middle of the movie.
Here are the short brief of some of physics concepts used in the “Interstellar”
What is Black hole?
As per physics, any mass if squeezed massively to
below “Schwarzschild radius”, it will become black hole. Mass may be anything, may
be its stone or tree or camera or humans. Schwarzschild radius is radius of imaginary
sphere.
Imagine
·
If the Mount Everest is squeezed to size
of white blood cell, it will become a black hole.
·
If the Earth is compressed to size of peanut,
it will become a black hole
Schwarzschild radius is defined by
where:
rs is the Schwarzschild radius;
G is the gravitational constant;
m is the mass of the object;
c is the speed of
light in vacuum.
Is the black holes are there in Universe? How they
are formed?
Yes, they are in the universe. They are formed when very
massive stars (more than hundreds of size of our sun) collapses at end of its
life. A star is a sphere of gas held together by
its own gravity. The force of gravity
is continually trying to cause the star to collapse, but this is counteracted
by the pressure of nuclear fusion inside the star core. This is called
hydrostatic support. When massive star reaches end of its lifecycle (entire
hydrogen got drained), the nuclear fusion stops. Eventually, when these
reactions no longer generate sufficient heat to support the star against its
own gravity, the star will collapse into an infinitesimally small point called
a SINGULARITY. The Singularity has an area around it, called the EVENT HORIZON.
Density of Singularity is infinite and Event Horizon is a notional boundary around a black hole beyond which no
light or other radiation can escape. Once formed black holes will continue to grow by absorbing nearby
mass including stars, planets, even other black holes
Black holes are also formed when neutron stars collide and collapse to form single entity. Generally black holes are present in center of every elliptical, spiral galaxy. Even our own milky way has super massive black hole namely Sagittarius A at its center
In the Interstellar, non-stationary spinning black
hole namely Gargantua has been shown. This spinning
black hole distorts the time and space and it is scientifically proven to be
accurate.
What is a worm hole?
If two Singularities
of a black hole can be merged in universe, worm tunnel can be formed. Worm
tunnel links extremely distant locations with shortcut of few miles apart. For example, to get from Earth to Alpha Centauri(nearest star), a
distance of 20 million million miles would have to be traveled
around the curve. By taking a short cut such as a wormhole, only a few million
miles would have to be traversed. The wormhole is direct, whereas the curved
route is much longer. The only other way to cut down on time is to travel
faster than the speed of light. The Theory of Relativity forbids this outlaw
speed. The speed of light limit has not been violated, because a short cut is
taken. The worm hole is still theoretical
not a practical proven concept. Worm hole was first proposed by Einstein and
his colleague Rosan
What is Time
Dilation?
According to “Thoery of Relativity”,
time gets bend due to differences in either gravity or velocity.
Relative velocity time dilation:
If someone
travel around the solar system at 50% the speed of light and then come back to
earth they will have experienced less local passage of time than others in
earth.They might have effectively have traveled to their future. Space orbiters
and planes are examples of velocity time dilation. Astronauts orbiting in ISS
and other orbiters will age slowly when compared to other human beings in
earth?
Gravitational Time
Dilation
Time in planets or
other bodies pass slowly near to strong gravitational fields, whereas it runs
fast near weak gravitational fields.
In the “Interstellar”
film, planet orbiting close to black hole has high gravitational force, so
clock ticks much much slower than on a spaceship which is farther away. As a
result, when Cooper and Amelia(main characters) spend few hours in the planet
and return to the spaceship, the other colleague romiley will inform them that
23 years had passed already.
Gravitational
Lensing:
As already saw that time
is bend by Gravitational field, gravitational field bends space and light. One of
the better examples of the concept is, stars behind our sun appear to be slightly
shifted from the original location. This phenomenon is due to sun’s
gravitational force which bends light coming from stars behind sun. When coming
to black hole, which has much more gravitational force distorts the light coming from farther
galaxies, and as a result light appears to have much smudge. This effect is
known as Gravitational lensing.
In the Interstellar film, Kip Thorne one of leading astrophysicist helped Christopher Nolan to create a black hole with the Gravitational lensing effect in background. Blackhole in the film is known as Gargantua. Gargantua’s accretion disc(just like Saturn rings) contains gas and dust which provides light and heat to gargantua’s planets. Black hole complex appearance is due to image of accretion disc being bent by gravitational lensing. One looping over the black hole and the other under it.
Conclusion:
Though the film has touched
so many complex science elements, its storyline is flawed and failed to support
the science. In some places, science laws were bend by Nolan to suit his film,
which has been criticized by many astrophysicists. One among them is entering
the black hole event horizon and safely reaching into some multidimensional
space having nonlinear time. As per physics any mass entering the black hole
event horizon will be spaghettified. Due to extreme tidal forces near black
hole, mass will be horizontally compressed and vertically stretched, which is
known as spaghettification.
Good science with bad
story is documentary, but a good story with bad science is still a good film. Interstellar
fits more for a documentary?
