Accelerating universe will limit technology
7 May 2004
The acceleration of the expansion of the universe places limits on future
developments in technology according to two US cosmologists. Lawrence Krauss
and Glenn Starkman of Case Western Reserve University have shown that the
acceleration could put a fundamental limit on the total amout of information
that can be stored and processed in the future
(arXiv.org/abs/astro-ph/0404510). They also calculate that Moore's Law will
remain valid for no more than 600 years -- although workers in the
semiconductor industry are more pessimistic and think that the famous law
will break down in the next decade or two.
It is well known that the amount of information that can be processed and
stored in any device is ultimately limited by the laws of quantum mechanics.
However, Krauss and Starkman have shown that the nature of the universe
itself also places limits on computation because it is not possible to
transmit or receive information beyond the so-called global event-horizon in
an accelerating universe.
The acceleration of the universe is driven by something that has repulsive
rather than attractive gravitational interactions. However, although this
so-called "dark energy" is thought to account for around two-thirds of the
universe, no one knows what it is made of. Possible explanations for dark
energy include a "cosmological constant" or something known as quintessence.
Krauss and Starkman have determined how far an observer could travel in such
a universe and still be able to transmit energy back to Earth. They then
determined how much energy could be transmitted this way. To calculate the
total amount of information that could be processed, they assumed that the
universe has a minimum temperature, below which no energy -- and therefore
no information -- can be extracted. Theory predicts that this minimum
temperature exists if the universe has a cosmological constant.
The duo calculated that the total number of computer bits that could be
processed in the future would be less than 1.35x10120. This means that the
effective information available to any observer within the event horizon of
an expanding universe will be significantly less than the total so-called
Hawking-Beckenstein entropy -- the entropy that is associated with a black
hole -- in the universe. Many cosmologists predict that an accelerating
universe will ultimately contain nothing but black holes, which will then
eventually disappear themselves.
"It is remarkable that results from cosmology can provide such definite
limits on the nature of technology," Krauss told PhysicsWeb. "In addition,
it is also remarkable that simple laws of physics put such robust
constraints on life, and technology, even when we don't know what that
technology will be like."
Krauss expects that the work will generate discussion on the limits of
computation, intelligence, consciousness and civilization. "Ultimately
arguments of this kind will have an impact on how we view ourselves, and our
place in the universe -- which is what science is all about."
Belle Dumé is Science Writer at PhysicsWeb
Bubba Do Wah Ditty
Just my sense of humour...very interesting and thought provoking actually
"Ricardo Morte" <email@example.com> wrote in message