Forward to the past?
Backward to the future? Sure, it happens in the movies, but could
real-world physics tell us anything about the possibility of human time
travel in the near future?
Curiosity contributor
Susan Sherwood examined the mind-blowing possibilities of time travel
via quantum foam and came up with the following answer.
Time travel through
wormholes is theoretically possible under the known laws of physics, and
quantum foam may be one piece of that puzzle. What is this foam? How
could it work? We have to delve into the tiny world of quantum mechanics
for some answers.
The basic laws of
Newtonian physics cover what we can see every day with our eyes: If you
let go of a book, it will fall; push a ball and it will roll. Quantum
mechanics concerns the tiniest, unseen parts of the world, parts even
smaller than subatomic particles. Measuring things on that scale is
tricky, and the smallest measurement used by physicists is the Planck
length, written as a one preceded by 34 zeros and a decimal point. This
is the size of the smallest particles that compose the fabric of
space-time [source:
Johnson].
At this miniscule scale,
it is theorized that tiny particles or black holes are fluctuating --
appearing and disappearing. This churning mix of particles is called
quantum foam. To visualize it, imagine a swimming pool full of boiling
water. Up close, you can see frothing and bubbles bursting, but if you
viewed a satellite photo of the pool, the surface would appear unbroken.
That's a comparison between what might be happening at the subatomic
level and what we see with our eyes according to the theory of quantum
foam.
What does this have to do
with wormholes? It is within quantum foam that wormholes are
theoretically believed to exist. They can move in and out of existence,
connecting different places and times. Since they are so incredibly
small, humans couldn't use them for time travel. Some theoretical
physicists, though, are exploring the concept of a wormhole time machine
-- the idea being that a wormhole might be ensnared and expanded until
it could become a transit for time travelers [source:
Hawking].
This is still in the
hypothetical stages, of course. However, a scientist at the University
of Maryland believes he can create a substance in a laboratory that
mimics quantum foam [source:
Technology Review]. This kind of study may help move quantum foam from a theoretical entity to a known quantity. Would H. G. Wells'
Time Machine (1895) then be far behind?