Panek begins by sorting
out what people have believed about the whatever-it-is that keeps us
standing upright on the ground and not floating away. He explores a
number of different creation stories offered by civilizations from
around the world and shows that one of the things they seem to have as a
common thread is the idea that "up there" is somehow different from
"down here." Up there, things stay suspended above the Earth's surface,
either because they're embedded in a dome or they fly or they're living
beings who fly. From there, observation during the time of the ancient
Greeks at least brought to Western thinking the realization that some of
the things up there moved around in a regular pattern. What, these
thinkers wondered, regulated it? What kept them up there while human
beings and just about everything they could see stayed down here?
The
answer of divine agency was enough for many, although as Galileo and
Copernicus led the way in proving some of the things up there related to
each other instead of to the Earth itself, and the Earth was revealed
to be moving in relation to the sun, instead of the other way around. As
developing sciences began to gain more and more tools to explore and
reveal the way the world works, the idea of divine agency didn't
disappear so much as open the door to a new question: How did God keep
what was up there up there and what was down here down here?
The
next chapters outline how first Isaac Newton and then others began to
conceive of a universal force that linked everything together, which
came to be called gravity. But as with nearly every answer since the
initial creation stories, more questions lurked underneath. As Albert
Einstein began to explore what the universe did as it got small, fast
and weird, the answers to his questions seemed to leave gravity
in a still more mysterious place. Defined as one of the four major
forces governing the universe, it differs from the other three in
significant ways and resists unification with them. Which is where,
despite the discovery of gravitational waves and other solid advances,
we are today: Not understanding gravity all that well and not
understanding that we don't really understand it all that well.
Panek
doesn't seem to aim at a recap of the latest gravitational
research and theory -- magazine articles might be best for that anyway,
given the pace of change in the field. Trouble seems more a
survey of the field that links some of our modern experimentation with
ancient mythologizing as they both grope frustratingly towards an answer
to something that exists all around us but which defies full
explanation. The ancients were stumped by what kept things up there from
falling down here; modern scientists are stumped by gravity's
resistance to being quantized like the other three forces.
Sometimes
Panek's breezy style gets in his way, as he winds up a sentence with a
punchline when it really needs stronger exposition. He makes enough
mistakes in relating Old Testament creation pericopes that a reader has
full license to wonder how well he does with the others, and that
section of the book is too long by half. It doesn't really weaken his
point that human beings have recognized the up-there/down-here
distinction for most of history but ordinarily accuracy is to be desired
in a book discussing scientific work.
Trouble is still a
fairly fun trip through the development of the ideas underlying our
understanding -- and, I suppose, misunderstanding -- of gravity. It
helps set the stage for better comprehension of such new discoveries as
may be made in coming years and makes a useful addition to the
layperson's science shelf.
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