Parallel Worlds Read Free Page A

data, the theories quickly
outpaced the data. In fact, the less the data, the fiercer the debate.
    Throughout the
history of cosmology, this paucity of reliable data also led to bitter,
long-standing feuds between astronomers, which often raged for decades. (For
example, just before astronomer Allan Sandage of the Mount Wilson Observatory
was supposed to give a talk about the age of the universe, the previous speaker
announced sarcastically, "What you will hear next is all wrong." And
Sandage, hearing of how a rival group had generated a great deal of publicity,
would roar, "That's a bunch of hooey. It's war—it's war!")
    THE AGE OF THE UNIVERSE
    Astronomers have been especially keen to know the age of the
universe. For centuries, scholars, priests, and theologians have tried to
estimate the age of the universe using the only method at their disposal: the
genealogy of humanity since Adam and Eve. In the last century, geologists have
used the residual radiation stored in rocks to give the best estimate of the
age of Earth. In comparison, the WMAP satellite today has measured the echo of
the big bang itself to give us the most authoritative age of the universe. The
WMAP data reveals that the universe was born in a fiery explosion that took
place 13.7 billion years ago.
    (Over the years,
one of the most embarrassing facts plaguing cosmology has been that the age of
the universe was often computed to be younger than the age of the planets and
stars, due to faulty data. Previous estimates for the age of the universe were
as low as 1 to 2 billion years, which contradicted the age of Earth [4.5
billion years] and the oldest stars [12 billion years]. These contradictions
have now been eliminated.)
    The WMAP has
added a new, bizarre twist to the debate over what the universe is made of, a
question that the Greeks asked over two thousand years ago. For the past
century, scientists believed that they knew the answer to this question. After
thousands of painstaking experiments, scientists had concluded that the
universe was basically made of about a hundred different types of atoms,
arranged in an orderly periodic chart, beginning with elemental hydrogen. This
forms the basis of modern chemistry and is, in fact, taught in every high
school science class. The WMAP has now demolished that belief.
    Confirming
previous experiments, the WMAP satellite showed that the visible matter we see
around us (including the mountains, planets, stars, and galaxies) makes up a
paltry 4 percent of the total matter and energy content of the universe. (Of
that 4 percent, most of it is in the form of hydrogen and helium, and probably
only 0.03 percent takes the form of the heavy elements.) Most of the universe
is actually made of mysterious, invisible material of totally unknown origin.
The familiar elements that make up our world constitute only 0.03 percent of
the universe. In some sense, science is being thrown back centuries into the
past, before the rise of the atomic hypothesis, as physicists grapple with the
fact that the universe is dominated by entirely new, unknown forms of matter
and energy.
    According to the
WMAP, 23 percent of the universe is made of a strange, undetermined substance
called dark matter, which has weight, surrounds the galaxies in a gigantic
halo, but is totally invisible. Dark matter is so pervasive and abundant that,
in our own Milky Way galaxy, it outweighs all the stars by a factor of i0.
Although invisible, this strange dark matter can be observed indirectly by
scientists because it bends starlight, just like glass, and hence can be
located by the amount of optical distortion it creates.
    Referring to the
strange results obtained from the WMAP satellite, Princeton astronomer John
Bahcall said, "We live in an implausible, crazy universe, but one whose
defining characteristics we now know."
    But perhaps the
greatest surprise from the WMAP data, data that sent the scientific community
reeling, was that 73 percent of the