in my view

By Jeff Bairstow

The next big thing:

the univ_Aerse as a computer

casual conversation with one of my cal world as we know it today. The first law of
neighbors, Edwin Taylor, who has taught thermodynamics relates to the conservation of
mechanical engineering at MIT for many energy when it is transformed from mechanical
years, recently led me to a quite startling energy into heat. This conservation can be easily
book by one of his younger colleagues, Seth Lloyd. observed empirically or calculated with some rea-
The book is “Programming the Universe: a Quan- sonable degree of precision and repeatability. The
tum Computer Scientist Takes on the Cosmos,” second law of thermodynamics, says Lloyd, is
(Knopf, New York, NY). In his just-published more of a statement about information and how it
book, Professor Lloyd poses a “really big ques- is processed at the microscopic scale.
tion”—“Is the universe really a very big computer In the language of the quantum computer scien-
and can it be programmed?” tist, each physical system contains a certain num-
That’s actually a two-part question, of course, ber of bits of information that are never decreased
and Lloyd appears to feel strongly that the an- by the processing and transforming that goes on.
swer to both parts is “yes!” He may be right. In In fact, claims Lloyd, the view of the universe as a
little more than a couple of hundred densely writ- computer can explain why the second law of ther-
ten pages, Lloyd makes a convincing case for the modynamics is true, something that scientists have
universe as a computer but he has not yet reached struggled over for more than a century and a half.
a definitive position on the latter half of his big Lloyd even manages to develop his concept of a
question, in my view. When and if he does, there computing universe sufficiently to put some num-
may be a Nobel Prize in the offing, I suspect. bers on the “ultimate laptop” (a computer with a
However, Lloyd is definitely not some mass of one kilogram and a volume of one liter

Johnny-come-lately computer nerd. Check where every elementary particle would be put to out his extensive 20-page curriculum vitae computational use). Such a laptop would be able on his personal web site ( www-me.mit.edu/ to perform ten million billion billion billion bil-people/personal/ slloyd.htm). And he is un- lion billion operations per second on ten thou-deniably well versed in theoretical phys- sand billion billion billion bits. Phew! ics, despite some youthful flippancy here And if you think those are really big numbers, and there. “Nothing is certain in life except wait until you read Lloyd’s take on the computa-death, taxes, and the second law of thermo- tional power of the universe. How about claiming, dynamics,” says Lloyd, his tongue firmly in as Lloyd brazenly does, that, since its beginning, his cheek. Indeed, starting with the concept the universe may have performed 10¹²² operations

IN FACT, CLAIMS LLOYD, THE VIEW OF THE UNIVERSE AS A COMPUTER CAN EXPLAIN WHY

THE SECOND LAW OF THERMODYNAMICS IS TRUE, SOMETHING THAT SCIENTISTS HAVE

STRUGGLED OVER FOR MORE THAN A CENTURY AND A HALF.

of entropy, Lloyd makes a comprehensible case for on 10⁹² bits. A billion here and a billion there and
the universe as a computer without having to revert soon we’re talking really, really big numbers! As
to complex math. Thank goodness for that! Lloyd further claims, “The information-processing
Entropy has never been easy to understand, ex- power of the universe grows steadily with time.
cept in an intuitive way. For example, when our The future looks rosy.”
bathwater cools down, it’s fairly easy to compre- I hope you are serious, Mr. Lloyd.
hend that entropy increases as the heat dissipates
into the cooler atmosphere. That’s clear enough, but
just where does entropy come from? And must en-
tropy always increase? Is Maxwell’s Demon possible
theoretically or otherwise? Lloyd attempts to answer Jeffrey Bairstow
these questions in the language of the informed lay- Contributing Editor
man, mostly with some success. jnbairstow@verizon.net
Lloyd then draws some parallels with the physi-