Travel
by bubble might seem more appropriate for witches in Oz, but two physicists
suggest that a future spaceship could fold a space-time bubble around itself to
travel faster than the speed of light.
We're
talking about the very distant future, of course.
The
idea involves manipulating dark energy — the mysterious force behind the
universe's ongoing expansion — to propel a spaceship forward without breaking
the laws of physics.
"Think of it
like a surfer riding a wave," said Gerald Cleaver, a physicist at Baylor
University. "The ship would be pushed by the spatial bubble and the bubble
would be traveling faster than the speed of light."
In theory,
the universe grew faster
than the speed of light for a very short time after the Big Bang, driven by
the dark energy that represents about 74 percent of the total mass-energy
budget in the universe. Dark matter constitutes 22 percent of the budget, and
normal matter (stars, planets and everything you see) makes up the remaining 4
percent or so.
Strange as
it sounds, current evidence supports the notion that the fabric of space-time
can expand faster than the speed of light, because the reality in which light
travels is itself expanding.
Cleaver and
Richard Obousy, a Baylor graduate student, tapped the latest idea in string
theory to devise how to manipulate dark
energy and accelerate a spaceship. Their notion is based on the Alcubierre
drive, which proposes expanding space-time behind the spaceship while also
shrinking space-time in front.
String
theorists had believed that a total of 10 dimensions exist, including height,
width, length and time. The other six dimensions exist largely as unknowns, but
everything is based on hypothetical one-dimensional strings. A newer theory,
called M-theory, suggests that those strings all vibrate in yet another
dimension.
Manipulating
that additional dimension would alter dark energy in terms of height, width,
and length, Cleaver and Obousy theorize. Such a capability would permit the altering
of space-time for a spaceship, taking advantage of dark energy's effect on
the universe.
"The
dark energy is simultaneously decreased just in front of the ship to decrease
(and bring to a stop) the expansion rate of the universe in front of the
ship," Cleaver told SPACE.com. "If the dark energy can be made
negative directly in front of the ship, then space in front of the ship would
locally contract."
This
loophole means that the spaceship would not conflict with Einstein's Theory of
Relativity, which states that objects accelerating to the speed of light
require an infinite amount of energy.
However, the
Baylor physicists estimate that manipulating dark energy through the extra
dimension requires energy equivalent to the converting the entire mass of
Jupiter into pure energy — enough to move a ship measuring roughly 33 feet (10
meters) by 33 feet by 33 feet.
"That is an
enormous amount of energy," Cleaver said. "We are still a very long ways off
before we could create something to harness that type of energy."
The workaround
solution may leave fans of Einstein pleased. But for now, faster-than-light
travel remains, like Oz, a pleasant
fantasy.
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