Parallel Worlds (10 page)

When Alpher and
Herman showed Gamow their final calculation of the temperature of the universe,
Gamow was disappointed. The temperature was so cold that it would be extremely
difficult to measure. It took Gamow a year to finally agree that the details
of their calculation were correct. But he despaired of ever being able to measure
such a faint radiation field. Instruments available in the 1940s were
hopelessly inadequate to measure this faint echo. (In a later calculation,
using an incorrect assumption, Gamow pushed the temperature of the radiation
up to 50 degrees.)

They gave a
series of talks to publicize their work. But unfortunately, their prophetic
result was ignored. Alpher has said, "We expended a hell of a lot of
energy giving talks about the work. Nobody bit; nobody said it could be
measured . . . And so over the period 1948 to 1955, we sort of gave up."

Undaunted,
Gamow, via his books and lectures, became the leading personality pushing the
big bang theory. But he met his match in a fierce adversary very much his
equal. While Gamow could charm his audience with his impish jokes and
witticisms, Fred Hoyle could overpower audiences with his sheer brilliance and
aggressive audacity.

FRED HOYLE, CONTRARIAN

The microwave background radiation gives us the "second
proof" of the big bang. But the man least likely to provide the third
great proof of the big bang via nucleosynthesis was Fred Hoyle, a man who
ironically spent almost his entire professional life trying to disprove the big
bang theory.

Hoyle was the
personification of an academic misfit, a brilliant contrarian who dared to defy
conventional wisdom with his sometimes pugnacious style. While Hubble was the
ultimate patrician, emulating the mannerisms of an Oxford don, and Gamow was
the entertaining jester and polymath who could dazzle audiences with his quips,
limericks, and pranks, Hoyle's style resembled that of a rough-hewn bulldog; he
seemed strangely out of place in the ancient halls of Cambridge University, the
old haunt of Isaac Newton.

Hoyle was born
in 1915 in northern England, the son of a textile merchant, in an area
dominated by the wool industry. As a child, he was excited by science; radio
was just coming to the village, and, he recalled, twenty to thirty people
eagerly wired up their homes with radio receivers. But the turning point in his
life came when his parents gave him a telescope for a present.

Hoyle's
combative style started when he was a child. He had mastered the
multiplication tables at age three, and then his teacher asked him to learn
Roman numerals. "How could anybody be so daft as to write VIII for
8?" he recalled scornfully. But when he was told that the law required him
to attend school, he wrote, "I concluded that, unhappily, I'd been born
into a world dominated by a rampaging monster called 'law' that was both
all-powerful and all-stupid."

His disdain for
authority was also cemented by a run-in with another teacher, who told the
class that a particular flower had five petals. Proving her wrong, he brought
the flower with six petals into class. For that impudent act of
insubordination, she whacked him hard in his left ear. (Hoyle later became deaf
in that ear.)

STEADY STATE THEORY

In the 1940s,
Hoyle was not enamored of the big bang theory. One defect in the theory was
that Hubble, because of errors in measuring light from distant galaxies, had
miscalculated the age of the universe to be 1.8 billion years. Geologists
claimed that Earth and the solar system were probably many billions of years
old. How could the universe be younger than its planets?

With colleagues
Thomas Gold and Hermann Bondi, Hoyle set out to construct a rival to the
theory. Legend has it that their theory, the steady state theory, was inspired
by a 1945 ghost movie called
Dead of
Night, starring Michael Redgrave. The movie consists of a
series of ghost stories, but in the final scene there is a memorable twist: the
movie ends just as it began. Thus the movie is circular, with no beginning or
end. This allegedly inspired the three to propose a theory of the universe that
also had no beginning or end. (Gold later clarified this story. He recalled,
"I think we saw that movie several months before, and after I proposed the
steady state, I said to them, 'Isn't that a bit like
Dead of Night?'")

In this model,
portions of the universe were in fact expanding, but new matter was constantly
being created out of nothing, so that the density of the universe remained the
same. Although he could give no details of how matter mysteriously emerged out
of nowhere, the theory immediately attracted a band of loyalists who battled
the big bang theorists. To Hoyle, it seemed illogical that a fiery cataclysm
could appear out of nowhere to send the galaxies hurtling in all directions;
he preferred the smooth creation of mass out of nothing. In other words, the
universe was timeless. It had no end, nor a beginning. It just was.

(The steady
state-big bang controversy was similar to the controversy affecting geology
and other sciences. In geology, there was the enduring debate between
uniformitarianism [the belief that Earth has been shaped by gradual changes in
the past] and catastrophism [which postulated that change took place via
violent events]. Although uniformitarianism still explains much of the geologic
and ecological features of Earth, no one can now deny the impact of comets and
asteroids, which have generated mass extinctions, or the breakup and movements
of the continents via tectonic drift.)

BBC LECTURES

Hoyle never
shied away from a good fight. In 1949, both Hoyle and Gamow were invited by the
British Broadcasting Corporation to debate the origin of the universe. During
the broadcast, Hoyle made history when he took a swipe at the rival theory. He
said fatefully, "These theories were based on the hypothesis that all the
matter in the universe was created in one big bang at a particular time in the
remote past." The name stuck. The rival theory was now officially christened
"the big bang" by its greatest enemy. (He later claimed that he did
not mean it to be derogatory. He confessed, "There is no way in which I
coined the phrase to be derogatory. I coined it to be striking.")

(Over the years,
proponents of the big bang have tried heroically to change the name. They are
dissatisfied with the common, almost vulgar connotation of the name and the
fact that it was coined by its greatest adversary. Purists are especially irked
that it was also factually incorrect. First, the big bang was not big (since
it originated from a tiny singularity of some sort much smaller than an atom)
and second, there was no bang (since there is no air in outer space). In August
1993,
Sky and Telescope
magazine
sponsored a contest to rename the big bang theory. The contest garnered
thirteen thousand entries, but the judges could not find any that was better
than the original.)

What sealed
Hoyle's fame to a whole generation was his celebrated BBC radio series on
science. In the 1950s, the BBC planned to air lectures on science every
Saturday evening. However, when the original guest canceled, the producers were
pressed to find a substitute. They contacted Hoyle, who agreed to come on.
Then they checked his file, where there was a note that said, "DO NOT USE
THIS MAN."

Fortuitously,
they ignored this dire warning from a previous producer, and he gave five
spell-binding lectures to the world. These classic BBC broadcasts mesmerized
the nation and in part inspired the next generation of astronomers. Astronomer
Wallace Sargent recalls the impact that these broadcasts had on him:
"When I was fifteen, I heard Fred Hoyle give lectures on the BBC called
'The Nature of the Universe.' The idea that you knew what the temperature and
density were at the center of the Sun came as a hell of a shock. At the age of
fifteen, that sort of thing seemed beyond knowledge. It was not just the
amazing numbers, but the fact that you could know them at all."

NUCLEOSYNTHESIS IN THE STARS

Hoyle, who
disdained idle armchair speculation, set out to test his steady state theory.
He relished the idea that the elements of the universe were cooked not in the
big bang, as Gamow believed, but in the center of stars. If the hundred or so
chemical elements were all created by the intense heat of the stars, then there
would be no need for a big bang at all.

In a series of
seminal papers published in the 1940s and 1950s, Hoyle and his colleagues laid
out in vivid detail how the nuclear reactions inside the core of a star, not
the big bang, could add more and more protons and neutrons to the nuclei of
hydrogen and helium, until they could create all the heavier elements, at least
up to iron. (They solved the mystery of how to create elements beyond mass
number 5, which had stumped Gamow. In a stroke of genius, Hoyle realized that
if there were a previously unnoticed unstable form of carbon, created out of
three helium nuclei, it might last just long enough to act as a
"bridge," allowing for the creation of higher elements. In the core
of stars, this new unstable form of carbon might last just long enough so that,
by successively adding more neutrons and protons, one could create elements
beyond mass number 5 and 8. When this unstable form of carbon was actually
found, it brilliantly demonstrated that nucleosynthesis could take place in
stars, rather than the big bang. Hoyle even created a large computer program
that could determine, almost from first principles, the relative abundances of
elements we see in nature.)

But even the
intense heat of the stars is not sufficient to "cook" elements beyond
iron, such as copper, nickel, zinc, and uranium. (It is extremely difficult to
extract energy by fusing elements beyond iron, for a variety of reasons,
including the repulsion of the protons in the nucleus and the lack of binding
energy.) For those heavy elements, one needs an even larger oven—the explosion
of massive stars, or supernovae. Since trillions of degrees can be attained in
the final death throes of a supergiant star when it violently collapses, there
is enough energy there to "cook" the elements beyond iron. This means
that most of the elements beyond iron were, in fact, blasted out of the
atmospheres of exploding stars, or supernovae.

In 1957, Hoyle,
as well as Margaret and Geoffrey Burbidge and William Fowler, published perhaps
the most definitive work detailing the precise steps necessary to build up the
elements of the universe and predict their known abundances. Their arguments
were so precise, powerful, and persuasive that even Gamow had to concede that
Hoyle had given the most compelling picture of nucleosynthesis. Gamow, in
typical fashion, even coined the following passage, written in biblical style.
In the beginning, when God was creating the elements,

In the excitement of counting, He missed calling for mass
five and so, naturally no heavier elements could have been formed. God was very
much disappointed, and wanted first to contract the Universe again, and to
start all over from the beginning. But it would be much too simple. Thus, being
almighty, God decided to correct His mistake in a most impossible way. And God
said, "Let there be Hoyle." And there was Hoyle. And God looked at
Hoyle . . . And told him to make heavy elements in any way he pleased. And
Hoyle decided to make heavy elements in stars, and to spread them around by
supernova explosions.

EVIDENCE AGAINST THE STEADY STATE

Over the
decades, however, evidence began to slowly mount against the steady state
universe on a number of fronts. Hoyle found himself fighting a losing battle.
In his theory, since the universe did not evolve but was continually creating
new matter, the early universe should look very much like the present-day
universe. Galaxies seen today should look very similar to galaxies billions of
years ago. The steady state theory could then be disproved if there were signs
of dramatic evolutionary changes during the course of billions of years.

In the 1960s,
mysterious sources of immense power were found in outer space, dubbed
"quasars," or quasi-stellar objects. (The name was so catchy that a
TV set was later named after it.) Quasars generated enormous amounts of power
and had huge redshifts, meaning that they were billions of light-years away,
and they also lit up the heavens when the universe was very young. (Today,
astronomers believe that these are gigantic young galaxies, driven by the
power of huge black holes.) We do not see evidence of any quasars today, though
according to the steady state theory they should exist. Over billions of years,
they have disappeared.

There was
another problem with Hoyle's theory. Scientists realized that there was simply
too much helium in the universe to fit the predictions of the steady state
universe. Helium, familiar as the gas found in children's balloons and blimps,
is actually quite rare on Earth, but it's the second most plentiful element in
the universe after hydrogen. It's so rare, in fact, that it was first found in
the Sun, rather than the Earth. (In 1868, scientists analyzed light from the
Sun that was sent through a prism. The deflected sunlight broke up into the
usual rainbow of colors and spectral lines, but the scientists also detected
faint spectral lines caused by a mysterious element never seen before. They
mistakenly thought it was a metal, whose names usually end in "ium,"
like lithium and uranium. They named this mystery metal after the Greek word
for sun, "helios." Finally in 1895, helium was found on Earth in
uranium deposits, and scientists embarrassingly discovered that it was a gas,
not a metal. Thus, helium, first discovered in the Sun, was born as a
misnomer.)