Edwin Hubble, though red-shifting of light from different
galaxies, discovered that space itself was getting bigger. Hubble’s discovery,
combined with non-Euclidean geometries indicated that the cosmos exists in more
than the three dimensions we’re acquainted with in everyday life. We essentially
don’t really see or sense more dimensions; nonetheless, theoretical physics suggests
that they should exist. This idea of more dimensions itself is way too interesting,
but the question is, are there any practical implications? Or can they actually
become part of applied physics? Well let’s dive into a little detail then:
Time Travel
Time is typically reflected as a dimension, essentially
it’s not a spatial dimension, and we’re definitely moving along the time axis
just okay. We don’t really have any technology to go backward in time and
change history. But according to theoretical physicists, if we could come up
with a way to travel through other dimensions, then it should let a sort of
tunneling to places that look unreachable from the perspective of the three
dimensions that we perceive.
The viewpoint of time travel into the past is, no
doubt, mind-boggling. But according to our current knowledge and some recent
researches it’s impossible. You can read more about these researches here.
Travelling into the future is no sci-fiction. For instance- accelerating from
the normal move into the future of one minute per minute, one year per year. Furthermore,
we actually know how to do it.
It’s called time dilation, it’s predicted by
Einstein’s theory of special relativity, and it will happen, if we accelerate a
spacecraft to a significant fraction of the speed of light. Travel very close
to the speed of light (c), and time slows down from your perspective and the
slowing is quantified by a variable known as the gamma factor. On a ship moving
just under 0.87c, the gamma factor = 2; thus, from the perspective of Earth-bound
observers, the traveler moves 2 minutes into the future for each minute that
seems to go by aboard the ship. At 0.94c, gamma = 3, and it increases more
dramatically as the ship approaches light speed asymptotically. At 0.9992c, for
instance, gamma reaches 25, which can advance you noticeably into the future if
you stay at that speed long enough. Make a round-trip to the star Vega, located
25 light-years away, and two years will pass by for you and your friends aboard
the ship (you’ll age two years and accumulate two years of memories), but
arriving on Earth you’ll find that you’ve jumped ahead by a half-century.
It really would happen; we’re certain, because
time dilation has been proven with subatomic particles in accelerators. We
can’t do it right now with people, but the capability for relativistic
velocities is only a matter of time (excuse the pun), since it could happen
with technology that may be just over the horizon, namely nuclear fusion.
Traversable Wormholes
Another means of transport made possible by a
multidimensional cosmos is wormholes. When Carl Sagan needed a realistic way
for humans to travel interstellar distances for his story Contact,
he consulted theoretical
physicist Kip Thorne. Working with a couple of his best graduate students at
the California Institute of Technology, Thorne worked out the
equations showing that, indeed, there was a way: a stable, traversable
wormhole, or even a system of such tunnels linking different areas of
space-time.
This was more than a decade before Miguel
Alcubierre would demonstrate that Einstein’s general relativity theory allowed
for Star Trek-style warp drive, so Sagan saw the wormhole concept as the only
scientifically-valid means by which his protagonist, Ellie Arroway, could be
shuttled through the galaxy quickly enough to meet storyline demands.
An advanced civilization could build a system of
wormhole-dependent tunnels connecting different points of the space-time
fabric, essentially drawing the departure and arrival points in the fabric into
close proximity to one another through a 4th dimension. If we
could do it, we could have an entry portal nearby, somewhere in the inner Solar
System that leads to an exit point at our destination, for instance a nearby star
system with an Earth-like planet. In science fiction, it’s the concept of a
star gate.
Warp Drive
Teaching about the 4th dimension,
physicists have used analogies, like drawings of something called a hypercube,
and even the 19th century novellaFlatland by Edwin
Abbott Abbott. The book imagines two-dimensional beings living on a planar
world that has only length and width. Unable to perceive a third dimension, the
Flatlanders see only one plane of three-dimensional visitors, kind of like how
computed tomography or magnetic resonance imaging shows the body in slices. Two
slices through a leg, one a few millimeters up from the other, look almost the
same, but a slice through the waist or chest gives a very different picture. We
can relate to this analogy, imagining our three-dimensional environment as just
one of an infinite number of slices of a four-dimensional environment.
But moving beyond four dimensions, it gets even
weirder, and very hard to visualize. The main theory here is called M theory,
which is a theory in physics that unites various types of what’s called
superstring theory. In M theory there are a bunch of dimensions, either 10 or
11, depending on who explains it to you. In addition to the three we’re
familiar with there arecompact dimensions. It’s all related to phenomena
called branes that vibrate like strings, but what’s most
relevant to this discussion is that the extra or compact dimensions don’t necessarily
have to remain compact. Like a jack-in-the box, it might be possible to unpack
the extra dimensions, says Richard Obousy, director of Icarus Interstellar, a non-profit
organization promoting starship research.
If an advanced civilization learns how to
manipulate higher dimensions, they might use them for technology, including
warp drive. So far, we don’t have a shred of evidence that the hypothesized
extra dimensions even exist. Someday, soon, we might get some evidence from the
Large Hadron Collider, but even then it’s anyone’s guess whether that would
lead to a warp drive technology.
