[Paleopsych] Michio Kaku: Escape from the universe
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Escape from the universe
Issue 107 / February 2005
Escape from the universe
The universe is destined to end. Before it does, could an advanced
civilisation escape via a "wormhole" into a parallel universe? The
idea seems like science fiction, but it is consistent with the laws of
physics and biology. Here's how to do it
The author is professor of theoretical physics at City University of
New York. This article is adapted from his book "Parallel Worlds"
The universe is out of control, in a runaway acceleration. Eventually
all intelligent life will face the final doomâthe big freeze. An
advanced civilisation must embark on the ultimate journey: fleeing to
a parallel universe.
In Norse mythology, Ragnarokâthe fate of the godsâbegins when the
earth is caught in the vice-like grip of a bone-chilling freeze. The
heavens themselves freeze over, as the gods perish in great battles
with evil serpents and murderous wolves. Eternal darkness settles over
the bleak, frozen land as the sun and moon are both devoured. Odin,
the father of all gods, finally falls to his death, and time itself
comes to a halt.
Does this ancient tale foretell our future? Ever since the work of
Edwin Hubble in the 1920s, scientists have known that the universe is
expanding, but most have believed that the expansion was slowing as
the universe aged. In 1998, astronomers at the Lawrence Berkeley
National Laboratory and the Australian National University calculated
the expansion rate by studying dozens of powerful supernova explosions
within distant galaxies, which can light up the entire universe. They
could not believe their own data. Some unknown force was pushing the
galaxies apart, causing the expansion of the universe to accelerate.
Brian Schmidt, one of the group leaders, said, "I was still shaking my
head, but we had checked everythingâ¦ I was very reluctant to tell
people, because I truly thought that we were going to get massacred."
Physicists went scrambling back to their blackboards and realised that
some "dark energy" of unknown origin, akin to Einstein's "cosmological
constant," was acting as an anti-gravity force. Apparently, empty
space itself contains enough repulsive dark energy to blow the
universe apart. The more the universe expands, the more dark energy
there is to make it expand even faster, leading to an exponential
In 2003, this astonishing result was confirmed by the WMAP (Wilkinson
microwave anisotropy probe) satellite. Orbiting at a million miles
from earth, this satellite contains two telescopes capable of
detecting the faint microwave radiation which bathes the universe. It
is so sensitive that it is able to photograph in exquisite detail the
afterglow of the microwave radiation left over from the big bang,
which is still circulating the universe. The WMAP satellite, in
effect, gave us "baby pictures" of the universe when it was a mere
380,000 years old.
The WMAP satellite settled the long-standing question of the age of
the universe: it is officially 13.7bn years old (to within 1 per cent
accuracy). But more remarkably, the data showed that dark energy is
not a fluke, but makes up 73 per cent of the matter and energy of the
entire universe. To deepen the mystery, the data showed that 23 per
cent of the universe consists of "dark matter," a bizarre form of
matter which is invisible but still has weight. Hydrogen and helium
make up 4 per cent, while the higher elements, you and I included,
make up just 0.03 per cent. Dark energy and most of dark matter do not
consist of atoms, which means that, contrary to what the ancient
Greeks believed and what is taught in every chemistry course, most of
the universe is not made of atoms at all.
As the universe expands, its energy content is diluted and
temperatures eventually plunge to near absolute zero, where even atoms
stop moving. One of the iron laws of physics is the second law of
thermodynamics, which states that in the end everything runs down,
that the total "entropy" (disorder or chaos) in the universe always
increases. This means that iron rusts, our bodies age and crumble,
empires fall, stars exhaust their nuclear fuel, and the universe
itself will run down, as temperatures drop uniformly to near zero.
Charles Darwin was referring to this law when he wrote: "Believing as
I do that man in the distant future will be a far more perfect
creature than he now is, it is an intolerable thought that he and all
other sentient beings are doomed to complete annihilation after such
long-continued slow progress." And one of the most depressing passages
in the English language was written by Bertrand Russell, who described
the "unyielding despair" he felt when contemplating the distant
future: "No fire, no heroism, no intensity of thought or feeling, can
preserve a life beyond the graveâ¦ all the labours of the ages, all
the devotion, all the inspiration, all the noonday brightness of human
genius, are destined to extinction in the vast death of the solar
system; and the whole temple of man's achievement must inevitably be
buried beneath the debris of a universe in ruins."
Russell wrote this passage in an era before space travel, so the death
of the sun does not seem so catastrophic todayâbut the death of the
entire universe seems inescapable. So on some day in the far future,
the last star will cease to shine, and the universe will be littered
with nuclear debris, dead neutron stars and black holes. Intelligent
civilisations, like homeless people in rags huddled next to dying
campfires, will gather around the last flickering embers of black
holes emitting a faint Hawking radiation.
String theory to the rescue?
Although thermodynamics and cosmology point to the eventual death of
all lifeforms in the universe, there is still one loophole. It is a
law of evolution that, when the environment changes radically, life
must adapt, flee or die. The first alternative seems impossible. The
last is undesirable. This leaves us with one choice: leave the
Although the concept of leaving our dying universe to enter another
seems utterly mad, there is no law of physics forbidding entering a
parallel universe. Einstein's general relativity theory allows for the
existence of "wormholes" or gateways connecting parallel universes,
sometimes called "Einstein-Rosen bridges." But it is still unknown
whether quantum corrections make such a journey possible or not.
Although once considered a preposterous idea, the concept of the
"multiverse"âthat our universe coexists with an infinite number of
parallel universesâhas recently generated much interest among
physicists from several directions. First, the leading theory
consistent with the WMAP data is the "inflationary" theory, proposed
by Alan Guth of MIT in 1979. It postulates a turbo-charged expansion
of the universe at the beginning of time. The inflationary universe
idea neatly explains several stubborn cosmological mysteries,
including the flatness and uniformity of the universe.
But since physicists still do not know what drove this rapid
inflationary process, there remains the chance that it could happen
again, in an endless cycle. This is the chaotic inflationary idea of
Andrei Linde of Stanford University, in which "parent universes" bud
"baby universes" in a continuous, neverending cycle. Like soap bubbles
which split into two smaller bubbles, universes can constantly sprout
from other universes.
But what caused the big bang and drove this inflation? The question
remains unanswered. Since the big bang was so intense, we have to
abandon Einstein's theory of general relativity, which forms the
underlying framework for all of cosmology. Einstein's theory of
gravity breaks down at the instant of the big bang, and hence cannot
answer the deep philosophical and theological questions raised by this
event. At these incredible temperatures, we must incorporate quantum
theoryâthe other great theory to emerge in the 20th centuryâwhich
governs the physics of the atom.
Quantum theory and Einstein's relativity theory are opposites. The
former governs the world of the very small, the peculiar subatomic
realm of electrons and quarks. Relativity theory rules the world of
the very largeâof black holes and expanding universes. Relativity,
therefore, is not suited to explaining the instant of the big bang,
where the universe was smaller than a subatomic particle. At this
moment we would expect radiation effects to dominate over gravity, and
hence we need a quantum description of gravity. Indeed, one of the
greatest challenges facing physics is to unify these theories into a
single, coherent theory of all the forces in the universe.
Physicists today are groping for this "theory of everything." Many
proposals have been made over the past half century, but all have been
shown to be inconsistent or incomplete. So far, the leadingâin fact,
the onlyâcandidate is string theory.
The latest incarnation of string theory, M-theory, may answer a
question which has dogged advocates of higher dimensions for a
century: where are they? Smoke can expand and fill up an entire room
without vanishing into hyperspace, so higher dimensions, if they exist
at all, must be smaller than an atom. If higher-dimensional space were
larger than an atom, then we should see atoms mysteriously drifting
and disappearing into a higher dimension, which we do not see in the
In the older string picture, one had to "curl" or wrap up six of the
ten original dimensions, leaving the four-dimensional universe of
today. These unwanted dimensions were squeezed into a tiny ball
(called a Calabi-Yau manifold) too small to be seen. But M-theory adds
a new twist to this: some of these higher dimensions can be large, or
even infinite, in size. Imagine two parallel sheets of paper. If an
ant lived on each sheet, each would think that its sheet was the
entire universe, unaware that there was another universe close by. In
fact, the other universe would be invisible. Each ant would live out
its life oblivious to the fact that another universe was only a few
inches away. Similarly, our universe may be a membrane floating in
11-dimensional hyperspace, while we remain oblivious of the parallel
universes hovering nearby.
One interesting version of M-theory cosmology is the "ekpyrotic" (from
the Greek for "conflagration") universe, proposed by Paul Steinhardt,
Burt Ovrut and Neil Turok. It assumes that our universe is a flat,
infinite membrane floating in higher-dimensional space. But
occasionally, gravity attracts a nearby membrane. These two parallel
universes race towards each other until they collide, releasing a
colossal amount of energy (the big splat). This explosion creates our
known universe and sends the two parallel universes flying apart in
Searching for higher dimensions
The intense interest in higher dimensions generated by string theory
has slowly spilled over into the world of experimental physics. Idle
dinner-table chatter is being translated into multimillion-dollar
At the University of Colorado in Denver, the first experiment was
conducted to search for the presence of a parallel universe, perhaps
only a millimetre away. Physicists searched for tiny deviations from
Newton's inverse square law for gravity. The light from a candle is
diluted as it spreads out, decreasing at the inverse square of the
distance of separation. Similarly, according to Newton's law, gravity
also spreads out over space and decreases in the same way. But in a
four-dimensional universe, there is more room for light or gravity to
spread out, so they decrease at the inverse cube of the distance.
Hence, by searching for tiny deviations from the inverse square law,
one may pick up the presence of the fourth dimension.
Newton's inverse square law is so precise that it can guide our space
probes throughout the solar system. But no one knows if it holds down
to the millimetre level. At present, only null results have been found
in these experiments. Other groups are searching for even smaller
deviations. Physicists at Purdue University in Indiana are trying to
test the law down to the atomic level, using nanotechnology.
Other avenues are also being explored. In 2007, the large hadron
collider (LHC), capable of blasting subatomic particles with a
colossal energy of 14 trillion electron volts (10 trillion times the
energy found in a typical chemical reaction) will be turned on outside
Geneva. The world's largest atom smasher, this huge machine, 27km in
circumference, straddling the French-Swiss border, will probe into
places 10,000 times smaller than a proton. Physicists expect to find
an entire zoo of new subatomic particles not seen since the big bang.
Physicists predict that the LHC may create exotic particles like
mini-black holes and supersymmetric particles, dubbed "sparticles,"
which would provide indirect evidence for string theory. In string
theory, every particle has a super-partner. The partner of the
electron is the "selectron," the partner of the quark is the "squark,"
and so on.
Furthermore, around 2012, the space-based gravity wave detector Lisa
(laser interferometer space antenna) will be sent into orbit. Lisa
will be able to detect the gravitational shockwaves emitted less than
a trillionth of a second after the big bang. It will consist of three
satellites circling the sun, connected by laser beams, making a huge
triangle in space 5m km on each side. Any gravitational wave which
strikes Lisa will disturb the lasers, and this tiny distortion will be
picked up by instruments, signalling the collision of two black holes
or the big bang aftershock itself. Lisa is so sensitiveâit can measure
distortions a tenth the diameter of an atomâthat it may be able to
test many of the scenarios being proposed for the pre-big bang
universe, including string theory.
Steps to leave the universe
Unfortunately, the energy necessary to manipulate these higher
dimensions, rather than just observe them, is far beyond anything
available to us in the foreseeable future: 10^19bn electron volts, or
a quadrillion times the energy of the large hadron collider. To
operate here one needs the technology of a super-advanced
In order to organise a discussion of advanced extraterrestrial
civilisations, astrophysicists often use the classification of Type I,
II and III civilisations introduced by Russian astrophysicist Nikolai
Kardashev in the 1960s, who ranked them by their energy consumption.
One might expect that a Type III civilisation, using the full power of
its unimaginably vast galactic resources, would be able to evade the
big freeze. The bodies of its citizens, for example, might be
genetically altered and their organs replaced by computerised
implants, representing a sophisticated merger of silicon and carbon
technologies. But even these superhuman bodies would not survive the
big freeze. This is because we define intelligence as the ability to
process information. According to physics, all machines, whether they
are computers, rockets, locomotives or steam engines, ultimately
depend on extracting energy from temperature differences: steam
engines, for example, work by extracting energy from boiling water.
But information-processing, and hence intelligence, requires energy
supplied by machines and motors, which will become impossible as
temperature differences drop to zero. According to the laws of
physics, in a uniformly cold universe where temperature differences do
not exist, intelligence cannot survive.
But since the big freeze is probably billions to trillions of years
away, there is time for a Type III civilisation to plot the only
strategy consistent with the laws of physics: leaving this universe.
To do this, an advanced civilisation will first have to discover the
laws of quantum gravity, which may or may not turn out to be string
theory. These laws will be crucial in calculating several unknown
factors, such as the stability of wormholes connecting us to a
parallel universe, and how we will know what these parallel worlds
will look like. Before leaping into the unknown, we have to know what
is on the other side. But how do we make the leap? Here are some of
Find a naturally occurring wormhole
An advanced civilisation which has colonised the galaxy may have
stumbled during its past explorations upon exotic, primordial
left-overs from the big bang. The original expansion was so rapid and
explosive that even tiny wormholes might have been stretched and blown
up into macroscopic size. Wormholes, cosmic strings, negative matter,
negative energy, false vacua and other exotic creatures of physics may
be relics left over from creation.
But if such naturally occurring gateways are not found, then the
civilisation will have to take more complex and demanding steps.
Send a probe through a black hole
Black holes, we now realise, are plentiful; there is one lurking in
the centre of our own milky way galaxy weighing about 3m solar masses.
Probes sent through a black hole may settle some unsolved questions.
In 1963, the mathematician Roy Kerr showed that a rapidly spinning
black hole will not collapse into a dot, but rather into a rotating
ring, which is kept from collapsing by centrifugal forces.
All black holes are surrounded by an event horizon, or point of no
return: passing through the event horizon is a one-way trip.
Conceivably, two such black holes would be needed for a return trip.
But to an advanced civilisation fleeing the big freeze, a one-way trip
may be all that is required.
What happens if one falls through the Kerr ring is a matter for
debate. Some believe that the act of entering the wormhole will close
it, making it unstable. And light falling into the black hole would be
blue-shifted, giving rise to the possibility that one might be fried
as one passed into a parallel universe. No one knows for sure, so
experiments must be done. This controversy heated up last year when
Stephen Hawking admitted that he had made a mistake 30 years ago in
betting that black holes gobble up everything, including information.
Perhaps the information is crushed forever by the black hole, or
perhaps it passes into the parallel universe on the other side of the
Kerr ring. Hawking's latest thinking is that information is not
totally lost. But no one believes that the final word on this delicate
question has been spoken.
To gain further data on space-times which are stretched to breaking
point, an advanced civilisation might create a black hole in slow
motion. In 1939, Einstein analysed a rotating mass of stellar debris
which was slowly collapsing under its own gravity. Although Einstein
showed that this rotating mass would not collapse into a black hole,
an advanced civilisation may duplicate this experiment in slow motion
by collecting a swirling mass of neutron stars weighing less than
about 3 solar masses and then gradually injecting extra stellar
material into the mass, forcing it to undergo gravitational collapse.
Instead of collapsing into a dot, it will collapse into a ring, and
hence allow scientists to witness the formation of a Kerr black hole
in slow motion.
Create negative energy
If Kerr rings prove to be too unstable or lethal, one might also
contemplate opening up wormholes via negative matter/energy. In 1988,
Kip Thorne and his colleagues at the California Institute of
Technology showed that if one had enough negative matter or negative
energy, one could use it to create a transversable wormholeâone in
which you could pass freely back and forth between your lab and a
distant point in space (and even time). Negative matter/energy would
be sufficient to keep the throat of the wormhole open for travel.
Unfortunately, no one has ever seen negative matter. In principle, it
should weigh less than nothing and fall up, rather than down. If it
existed when the earth was created, it would have been repelled by the
earth's gravity and drifted off into space.
Negative energy, however, has been seen in the laboratory in the form
of the Casimir effect. Normally, the force between two uncharged
parallel plates should be zero. But if quantum fluctuations outside
the plates are greater than the fluctuations between the plates, a net
compression force will be created. The fluctuations pushing the plates
from the outside are larger than the fluctuations pushing out from
within the plates, so these uncharged plates are attracted to each
This was first predicted in 1948 and measured in 1958. However, the
Casimir energy is tinyâproportional to the inverse fourth power of the
separation of the plates. To make use of the Casimir effect would
require advanced technology to squeeze these parallel plates to very
small separations. If one were to reshape these parallel plates into a
sphere with a double lining, and use vast amounts of energy to press
these spherical plates together, enough negative energy might be
generated for the interior of the sphere to separate from the rest of
Another source of negative energy is laser beams. Pulses of laser
energy contain "squeezed states," which contain negative as well as
positive energy. The problem is separating the negative from the
positive energy within the beam. Although this is theoretically
possible, it is exceedingly difficult. If a sophisticated civilisation
could do this, then powerful laser beams might generate enough
negative energy for the sphere to peel from our universe.
Even black holes have negative energy surrounding them, near their
event horizons. In principle, this may yield vast quantities of
negative energy. However, the technical problems of extracting
negative energy so close to a black hole are extremely tricky.
Create a baby universe
According to inflation, just a few ounces of matter might suffice to
create a baby universe. This is because the positive energy of matter
cancels out the negative energy of gravity. If the universe is closed,
then they cancel out exactly. In some sense, the universe may be a
free lunch, as Guth has emphasised. Strange as it may seem, it
requires no net energy to create an entire universe. Baby universes
are in principle created naturally when a certain region of space-time
becomes unstable and enters a state called the "false vacuum," which
destabilises the fabric of space-time. An advanced civilisation might
do this deliberately by concentrating energy in a single region. This
would require either compressing matter to a density of 10^80g/cm3, or
heating it to 10^29 degrees kelvin.
To create the fantastic conditions necessary to open up a wormhole
with negative energy or to create a false vacuum with positive energy,
one might need a "cosmic atom-smasher." Physicists are attempting to
build "table-top" accelerators that can, in principle, attain billions
of electron volts on a kitchen table. They have used powerful laser
beams to attain an energy acceleration of 200bn electron volts per
metre, a new record. Progress is rapid, with the energy growing by a
factor of ten every five years. Although technical problems still
prevent a true table-top accelerator, an advanced civilisation has
billions of years to perfect these and other devices.
To reach the Planck energy (10^28eV) with this laser technology would
require an atom-smasher ten light years long, beyond the nearest star,
which would be well within the technological capabilities of a Type
III civilisation. Since the vacuum of empty space is better than any
vacuum attainable on the earth, the beam of subatomic particles may
not need light years of tubing to contain it; it could be fired in
empty space. Power stations would have to be placed along the path in
order to pump laser energy into the beam, and also to focus it.
Another possibility would be to bend the path into a circle so that it
fits within the solar system. Gigantic magnets could be placed on
asteroids to bend and focus the beam in a circular path around the
sun. The magnetic field necessary to bend the beam would be so huge
that the surge of power through the coils might melt them, meaning
that they could only be used once. After the beam had passed, the
melted coils would have to be discarded and replaced in time for the
Build a laser implosion machine
In principle, it might be possible to create laser beams of limitless
power; the only constraints are the stability of the lasing material
and the energy of the power source. In the lab, terawatt (trillion
watt) lasers are now common, and petawatt (quadrillion watt) lasers
are slowly becoming possible (in comparison, a commercial nuclear
power plant generates only a billion watts of continuous power). One
can even envisage an X-ray laser powered by the output of a hydrogen
bomb, which would carry unimaginable power in its beam. At the
Lawrence Livermore National Laboratory, a battery of lasers is fired
radially on a small pellet of lithium deuteride, the active ingredient
of a hydrogen bomb, in order to tame the power of thermonuclear
An advanced civilisation might create huge laser stations on the
asteroids and then fire millions of laser beams on to a single point,
creating vast temperatures and pressures unimaginable today.
Send a nanobot to recreate civilisation
If the wormholes created in the previous steps are too small, too
unstable, or the radiation effects too intense, then perhaps we could
send only atom-sized particles through a wormhole. In this case, this
civilisation may embark upon the ultimate solution: passing an
atomic-sized "seed" through the wormhole capable of regenerating the
civilisation on the other side. This process is commonly found in
nature. The seed of an oak tree, for example, is compact, rugged and
designed to survive a long journey and live off the land. It also
contains all the genetic information needed to regenerate the tree.
An advanced civilisation might want to send enough information through
the wormhole to create a "nanobot," a self-replicating atomic-sized
machine, built with nanotechnology. It would be able to travel at near
the speed of light because it would be only the size of a molecule. It
would land on a barren moon, and then use the raw materials to create
a chemical factory which could create millions of copies of itself. A
horde of these robots would then travel to other moons in other solar
systems and create new chemical factories. This whole process would be
repeated over and over again, making millions upon millions of copies
of the original robot. Starting from a single robot, there will be a
sphere of trillions of such robot probes expanding at near the speed
of light, colonising the entire galaxy.
(This was the basis of the movie 2001, probably the most
scientifically accurate fictional depiction of an encounter with an
extraterrestrial lifeform. Instead of meeting aliens in a flying
saucer or the USS Enterprise, the most realistic possibility is that
we will make contact with a robot probe left on a moon from a passing
Type III civilisation. This was outlined by scientists in the opening
minutes of the film, but Stanley Kubrick cut the interviews from the
Next, these robot probes would create huge biotechnology laboratories.
The DNA sequences of the probes' creators would have been carefully
recorded, and the robots would have been designed to inject this
information into incubators, which would then clone the entire
species. An advanced civilisation may also code the personalities and
memories of its inhabitants and inject this into the clones, enabling
the entire race to be reincarnated.
Although seemingly fantastic, this scenario is consistent with the
known laws of physics and biology, and is within the capabilities of a
Type III civilisation. There is nothing in the rules of science to
prevent the regeneration of an advanced civilisation from the
molecular level. For a dying civilisation trapped in a freezing
universe, this may be the last hope.
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