[Bookwoman] Warped Passages by Lisa Randall

[Lee Anne Phillips]

Warped Passages: Unraveling the Mysteries 
of the Universe's Hidden Dimensions
By Lisa Randall

A Notable Book of the Year from the
New York Times Book Review

Lisa Randall was the first tenured woman in
the Princeton Physics Department and the 
first tenured woman theoretical physicist at
MIT and Harvard, a leading expert on particle
physics, string theory, and cosmology but 
surprisingly accessible, despite the rarified 
atmosphere of her usual circle of colleagues,
in this very readable popular explanation of 
what theoretical physicists talk about in their
journals and periodic conclaves.

Although she doesn't address string theory
explicitly in this book -- there are plenty
which do -- she does tackle one of the
theoretical underpinnings of string theory,
the notion that there are other dimensions
than the three plus time we're familiar with
in everyday life, and clearly explains how
they might work, and what sort of problems
they might solve. 

One of the weightier problems in modern
physics is gravity. From our own perspective,
it's astonishingly noticeable - especially if
we happen to be standing at the edge of a
tall cliff -- and one of the few we have an
instinctive fear of. The only other force we
run into in daily life is electromagnetism, 
and most of us have no particular awareness 
of it, unless we happen to run into a live wire
and receive a shock, or ponder the workings 
of a refrigerator magnet or compass. 

But gravity is also -- contrary to our own
fearful perception of it -- extremely, almost 
laughably, weak. 

If we were to fall from the very top of the 
Empire State Building, the electrical repulsion 
which exists between the electrons circling the 
atoms of our body and the electrons circling 
the atoms of the sidewalk would bring us to 
an almost instantaneous stop, with drastic 
results for ourselves, if not the sidewalk. 

We would have to be accelerated almost to 
the speed of light before our atoms would 
overcome the electromagnetic force and
intermingle with the atoms of the sidewalk 
and cause other than superficial interactions. 

The very weak force exerted by gravity is also
*very* simple, so simple that it was among the 
first physical forces to be discovered and 
described, so that Isaac Newton could describe 
the trajectory of the planets, or that of a 
cannonball, more or less perfectly in the 
Seventeenth Century, despite the fact that
Newton was no atomic physicist. Rocket 
scientists haven't really made much
progress beyond Newton, other than
having to take into account Relativity
and time dilation when plotting very
long journeys.

This simple theory of gravity has proven 
difficult, however, to reconcile with our 
latest discoveries, atomic particles and the 
atomic forces, including electromagnetism, 
and the so-called "strong" and "weak" forces.

The strong force binds the nucleus of the atom 
together, and is very strong indeed, for which we
can all be grateful since, otherwise, our atoms
would fly apart at the slightest provocation.

The electromagnetic force is 137 times weaker, 
but still pretty strong, since it holds the outer
electron shells of atoms together and keeps
atoms from collapsing into each other, which
would allow us all to melt together into a sort
of neutron soup.

The weak force is a million times weaker than
the strong force, but still very important, since
it allows quarks to interact with each other and,
by the way, allows the Sun to shine, without
which our prospects for continued existence
would be pretty dim.

But the force of gravity is so very much smaller 
than even the weak force, six times ten to the 
minus thirty-ninth power less than the strong 
force, that it boggles the imagination.
 
If translated to size, that's quite a bit more than 
the difference in size between the entire universe 
and a single atom within the universe. 

The Standard Model can't easily account for
this sort of enormous discrepancy between the
strengths of the other forces, although the middle
two can be fairly reliably bundled together into 
what's sometimes called electroweak unification.

The strong force may have a tentative explanation
in any of the Grand Unified Theories floating around,
but all of them so far imply that neutrons decay --
very slowly we hope -- and that the atoms that we
and everything else are made up of will eventually,
like the Snark, softly and silently vanish away.

People are assiduously looking for proton decay,
but haven't found any yet, and there are other
problems, since the enormous forces involved 
imply "atomic particles" (the X-boson) so huge 
that they are more or less visible to the naked eye. 

All in all, putting everything together so it makes
sense is very hard to do, and has been so mystifying
that the problem has bedeviled those looking for a 
Theory of Everything for quite some time now and
has aroused hostility in a very few, since the
experiments one might contemplate to prove any
such theory have been either impossible or dicey. 

Ms. Randall shows how it would be possible to 
dilute the effect of gravity if it were spread out 
through many dimensions, yet still allow the 
normal universe to go on merrily about us as 
if three dimensions plus time were all that were 
needed in daily life, making everything simpler.
(Despite the complication of extra dimensions.)

And really, extra dimensions aren't much of 
a stretch for at least some of us -- in the
USA at least -- since we have many citizens
who believe in much more difficult concepts
with no trouble at all.  

Extra dimensions are a pretty slick concept, 
and they've been incorporated (in one form 
or another) into most of the String Theory 
models, of which it must be confessed that 
there are quite a few, so many that a few 
theoretical physicists have thrown up their 
hands and said, "Fooey! The Standard Model 
was good enough for granddaddy and it's 
good enough for me! All we have to do is 
do a little darning at the edges and it will 
be almost as good as new."

For myself, I'm guessing that the Standard Model 
is just a little too frayed to be readily fixable, and
have some hopes that the Large Hadron Collider
coming online in 2007 may soon begin to solve
some of these mysteries in a slightly more
definitive way. 

It had better solve *something*, since large
colliders are wickedly expensive to build and
this one is sometimes called the "Last Hope
Collider," since ambiguous or no new results
may prevent funding a larger model for many
years to come.

If you truly interested in *Everything*, this
may be the book for you, and the hard bits
are nicely segregated so that you don't have
to be a nuclear physicist to understand it.

And I have to confess that, in a field dominated
by men, however personally charming and modest, 
the prospect of reading a book by a woman 
excited me. I bought it in hardcover (first
edition) which may illustrate my enthusiasm,
since I'm notoriously frugal. 

Cheers,

Lee Anne
=============================
If you really want to upset your parents, 
and you don't have enough courage to be 
gay, go into the arts! 
                   -- Kurt Vonnegut