Did the big bang really happen? [New Scientist July '02]


WHAT if the big bang never happened? Ask cosmologists this and they'll
usually tell you it is a stupid question. The evidence, after all, is
written in the heavens. Take the way galaxies are scattered across the
sky, or witness the fading afterglow of the big bang fireball. Even the
way the atoms in your body have come into being over the eons. They are
all smoking guns that point to the existence 13.7 billion years ago of
an ultra-hot, ultra-dense state known as the big bang.

Or are they? A small band of researchers is starting to ask the
question no one is supposed to ask. Last week the dissidents met to
review the evidence at the first ever Crisis in Cosmology conference in
Monção, Portugal. There they argued that cosmologists' most cherished
theory of the universe fails to explain certain crucial observations.
If they are right, the universe could be a lot weirder than anyone
imagined. But before venturing that idea, say the dissidents, it is
time for some serious investigation into the big bang's validity and
its alternatives.

"Look at the facts," says Riccardo Scarpa of the European Southern
Observatory in Santiago, Chile. "The basic big bang model fails to
predict what we observe in the universe in three major ways." The
temperature of today's universe, the expansion of the cosmos, and even
the presence of galaxies, have all had cosmologists scrambling for
fixes. "Every time the basic big bang model has failed to predict what
we see, the solution has been to bolt on something new - inflation,
dark matter and dark energy," Scarpa says.

For Scarpa and his fellow dissidents, the tinkering has reached an
unacceptable level. All for the sake of saving the notion that the
universe flickered into being as a hot, dense state. "This isn't
science," says Eric Lerner who is president of Lawrenceville Plasma
Physics in West Orange, New Jersey, and one of the conference
organisers. "Big bang predictions are consistently wrong and are being
fixed after the event." So much so, that today's "standard model" of
cosmology has become an ugly mishmash comprising the basic big bang
theory, inflation and a generous helping of dark matter and dark
energy.

The fact that the conference went ahead at all is an important step
forward, say its organisers. Last year they wrote an open letter
warning that failure to fund research into big bang alternatives was
suppressing free debate in the field of cosmology (New Scientist, 22
May 2004, p 20).

The trouble, says Lerner, who headed the list of more than 30
signatories, is that cosmology is bankrolled by just a few sources, and
the committees that control those purse strings are dominated by
supporters of the big bang. Critics of the standard model of cosmology
are not just uncomfortable about the way they feel it has been cobbled
together. They also point to specific observations that they believe
cast doubt on cosmology's standard model.
"Dark matter is turning up in places where it shouldn't exist"

Take the most distant galaxies ever spotted, for example. According to
the accepted view, when we observe ultra-distant galaxies we should see
them in their youth, full of stars not long spawned from gas clouds.
This is because light from these faraway galaxies has taken billions of
years to reach us, and so the galaxies must appear as they were shortly
after the big bang. But there is a problem. "We don't see young
galaxies," says Lerner. "We see old ones."

He cites recent observations of high-red-shift galaxies from NASA's
Spitzer space telescope. A galaxy's red shift is a measure of how much
the universe has expanded since it emitted its light. As the light
travels through an expanding universe, its wavelength gets stretched,
as if the light wave were drawn on a piece of elastic. The increase in
wavelength corresponds to a shift towards the red end of the spectrum.

The Spitzer galaxies have red shifts that correspond to a time when the
universe was between about 600 million and 1 billion years old.
Galaxies this young should be full of newborn stars that emit blue
light because they are so hot. The galaxies should not contain many
older stars that are cool and red. "But they do," says Lerner.

Spitzer is the first telescope able to detect red stars in faraway
galaxies because it is sensitive to infrared light. This means it can
detect red light from stars in high-red-shift galaxies that has been
pushed deep into the infrared during its journey to Earth. "It turns
out these galaxies aren't young at all," says Lerner. "They have pretty
much the same range of stars as present-day galaxies."

And that is bad news for the big bang. Among the stars in today's
galaxies are red giants that have taken billions of years to burn all
their hydrogen and reach this bloated phase. So the Spitzer
observations suggest that some of the stars in ultra-distant galaxies
are older than the galaxies themselves, which plunges the standard
model of cosmology into crisis.
Fog-filled universe

Not surprisingly, cosmologists have panned Lerner's theories. They put
the discrepancy down to large uncertainties in estimating the ages of
galaxies. But Lerner has a reply. He points to other distant objects
that appear much older than they ought to be. "At high red shift, we
also observe clusters and huge superclusters of galaxies," he says,
arguing that it would have taken far longer than a billion years for
galaxies to clump together to form such giant structures.

His solution to the puzzle is extreme. Rather than being caused by the
expanding universe, he believes that the red shift is down to some
other mechanism. But at this stage it is only a guess. "I admit I don't
know what that mechanism might be," Lerner says, "though I believe it
is intrinsic to light."

To test his idea, he would like to see sensitive experiments on Earth
capable of detecting minute changes in light. One possibility would be
to modify the LIGO detector in Hanford, Washington state. LIGO is
designed to detect gravitational waves, the warps in space-time created
by events such as neutron star collisions. To do this it bounces
perpendicular beams of laser light hundreds of times between mirrors 4
kilometres apart, looking for subtle shifts in the beams' lengths. With
a few tweaks, Lerner believes that LIGO could be modified to measure
any intrinsic red-shifting that light might undergo.

If the experiment ever gets the go-ahead and Lerner is proved right,
the implications would be immense, not least because the tapestry of
cosmology as we know it would unravel. Without an expanding universe,
there would be no need to invoke dark energy to account for the
apparent acceleration of that expansion. Nor would there be any reason
to suppose the big bang was the ultimate beginning. "I can prove that
the universe wasn't born 13.7 billion years ago," says Lerner. "The big
bang never happened."

However, Lerner's claims leave plenty of awkward questions. Among them
is the matter of the cosmic microwave background. First detected in
1965, the vast majority of cosmologists believe that this faint,
all-pervading soup of microwaves is the dying glow of the big bang, and
proof of the ultimate beginning. According to big bang theory, the hot
radiation that filled space after the birth of the universe has been
trapped inside ever since because it has nowhere else to go. As the
universe expanded over the past 13.7 billion years, the radiation has
cooled to today's temperature of less than 3 kelvin above absolute
zero.

So if there was no big bang, where did the cosmic microwave background
come from? Lerner believes that cosmologists have got the origin of the
microwave glow all wrong. "If you wake up in a tent and everything
around you is white, you don't conclude you've seen the start of the
universe," he says. "You conclude you're in fog."

Rather than coming from the big bang, Lerner believes that the cosmic
background radiation is really starlight that has been absorbed and
re-radiated. It is an old idea that was widely promoted by the late
cosmologist and well-known big bang sceptic Fred Hoyle. He believed
that starlight was absorbed by needle-like grains of iron ejected by
supernovae and then radiated as microwaves. But Hoyle never found any
evidence to back up his ideas and many cosmologists dismissed them.
"Some of the stars in distant galaxies appear older than the universe
itself"

Lerner's idea is similar, though he thinks that threads of electrically
charged gas called plasma are responsible, rather than iron whiskers.
Jets of plasma are squirted into intergalactic space by highly
energetic galaxies known as quasars, and Lerner believes that such
plasma filaments continually fragmented until they filled the universe
like fog. This fog then scattered the infrared light radiated by dust
that had in turn absorbed starlight. By doing so, Lerner believes, the
infrared radiation became uniform in all directions, just as the cosmic
microwave background appears to be.

All this is possible, he argues, because standard cosmology theory has
overlooked processes involving plasmas. "All astronomers know that
99.99 per cent of matter in the universe is in the form of plasma,
which is controlled by electromagnetic forces," he says. "Yet all
astronomers insist on believing that gravity is the only important
force in the universe. It is like oceanographers ignoring
hydrodynamics." To make progress, Lerner is calling for theories that
include plasma phenomena as well as gravity, and for more rigorous
testing of theory against observations.

Of course, Lerner's ideas are extremely controversial and few people
are convinced, but that doesn't stop other researchers questioning the
standard theory too. They have their own ideas about what is wrong with
it. In Scarpa's case, the mysterious dark matter is at fault.

Dark matter has become an essential ingredient in cosmology's standard
model. That's because the big bang on its own fails to describe how
galaxies could have congealed from the matter forged shortly after the
birth of the universe. The problem is that gas and dust made from
normal matter were spread too evenly for galaxies to clump together in
just 13.7 billion years. Cosmologists fix this problem by adding to
their brew a vast amount of invisible dark matter which provides the
extra tug needed to speed up galaxy formation.

The same gravitational top-up helps to explain the rapid motion of
outlying stars in galaxies. Astronomers have measured stars orbiting
their galactic centres so fast that they ought to fly off into
intergalactic space. But dark matter's extra gravity would explain how
the galaxies hold onto their speeding stars. Similarly, dark matter is
needed to explain how clusters of galaxies can hold on to galaxies that
are orbiting the cluster's centre so fast they ought to be flung away.

But dark matter may not be the cure-all it seems, warns Scarpa. What
worries him are inconsistencies with the theory. "If you believe in
dark matter, you discover there is too much of it," he says. In
particular, his observations point to dark matter in places
cosmologists say it shouldn't exist. One place no one expects to see it
is in globular clusters, tight knots of stars that orbit the Milky Way
and many other galaxies. Unlike normal matter, the dark stuff is
completely incapable of emitting light or any other form of
electromagnetic radiation. This means a cloud of the stuff cannot
radiate away its internal heat, a process vital for gravitational
contraction, so dark matter cannot easily clump together at scales as
small as those of globular clusters.

Scarpa's observations tell a different story, however. He and his
colleagues have found evidence that the stars in globular clusters are
moving faster than the gravity of visible matter can explain, just as
they do in larger galaxies. They have studied three globular clusters,
including the Milky Way's biggest, Omega Centauri, which contains about
a million stars. In all three, they find the same wayward behaviour. So
if isn't dark matter, what is going on?

Scarpa's team believes the answer might be a breakdown of Newton's law
of gravity, which says an object's gravitational tug is inversely
proportional to the square of your distance from it. Their observations
of globular clusters suggest that Newton's inverse square law holds
true only above some critical acceleration. Below this threshold
strength, gravity appears to dissipate more slowly than Newton
predicts.

Exactly the same effect has been spotted in spiral galaxies and
galaxy-rich clusters. It was identified more than 20 years ago by
Mordehai Milgrom at the Weizmann Institute in Rehovot, Israel, who
proposed a theory known as modified Newtonian dynamics (MOND) to
explain it. Scarpa points out that the critical acceleration of 10-10
metres per second per second that was identified for galaxies appears
to hold for globular clusters too. And his work has led him to the same
conclusion as Milgrom: "There is no need for dark matter in the
universe," says Scarpa.

It is a bold claim to make. And not surprisingly, MOND has had plenty
of critics over the years. One of cosmologists' biggest gripes is that
MOND is not compatible with Einstein's theory of relativity, so it is
not valid for objects travelling close to the speed of light or in very
strong gravitational fields. In practice, this means MOND has been
powerless to make predictions about pulsars, black holes and, most
importantly, the big bang. But this has now been fixed by Jacob
Bekenstein at the Hebrew University of Jerusalem in Israel.

Bekenstein's relativistic version of the theory already appears to be
bearing fruit. In May a team led by Constantinos Skordis of the
University of Oxford showed that relativistic MOND can make
cosmological predictions. The researchers have reproduced both the
observed properties of the cosmic microwave background and the
distribution of galaxies throughout the universe
(www.arxiv.org/abs/astro-ph/0505519).
Gravity in crisis

Scarpa believes that MOND is a crucial body blow for the big bang. "It
means that the law of gravity from which we derive the big bang is
wrong," he says. He insists that cosmologists are interpreting
astronomical observations using the wrong framework. And he urges them
to go back to the drawing board and derive a cosmological model based
on MOND.

For now, his plea seems to be falling mostly on deaf ears. Yet there is
more evidence that there could be something wrong with the standard
model of cosmology. And it is evidence that many cosmologists are
finding harder to dismiss because it comes from the jewel in the crown
of cosmology instruments, the Wilkinson Microwave Anisotropy Probe. "It
could be telling us something fundamental about our universe, maybe
even that the simplest big bang model is wrong," says João Magueijo of
Imperial College London.

Since its launch in 2001, WMAP has been quietly taking the temperature
of the universe from its vantage point 1.5 million kilometres out in
space. The probe measures the way the temperature of the cosmic
microwave background varies across the sky. Cosmologists believe that
the tiny variations from one place to another are an imprint of the
state of the universe about 300,000 years after the big bang, when
matter began to clump together under gravity. Hotter patches correspond
to denser regions, and cooler patches reflect less dense areas. These
density variations began life as quantum fluctuations in the vacuum in
the first split second of the universe's existence, and were
subsequently amplified by a brief period of phenomenally fast expansion
called inflation.

Because the quantum fluctuations popped up at random, the hot and cold
spots we see in one part of the sky should look much like those in any
other part. And because the cosmic background radiation is a feature of
the universe as a whole rather than any single object in it, none of
the hot or cold regions should be aligned with structures in our corner
of the cosmos. Yet this is exactly what some researchers are claiming
from the WMAP results.

Earlier this year, Magueijo and his Imperial College colleague Kate
Land reported that they had found a bizarre alignment in the cosmic
microwave background. At first glance, the pattern of hot and cold
spots appeared random, as expected. But when they looked more closely,
they found something unexpected. It is as if you were listening to an
anarchic orchestra playing some random cacophony, and yet when you
picked out the violins, trombones and clarinets separately, you
discovered that they are playing the same tune.

Like an orchestral movement, the WMAP results can be analysed as a
blend of patterns of different spatial frequencies. When Magueijo and
Land looked at the hot and cold spots this way, they noticed a striking
similarity between the individual patterns. Rather than being spattered
randomly across the sky, the spots in each pattern seemed to line up
along the same direction. With a good eye for a newspaper headline,
Magueijo dubbed this alignment the axis of evil. "If it is true, this
is an astonishing discovery," he says.
"Without an expanding universe, the big bang was not the ultimate
beginning"

That's because the result flies in the face of big bang theory, which
rules out any such special or preferred direction. So could the weird
effect be down to something more mundane, such as a problem with the
WMAP satellite? Charles Bennett, who leads the WMAP mission at NASA's
Goddard Space Flight Center in Greenbelt, Maryland, discounts that
possibility. "I have no reason to think that any anomaly is an artefact
of the instrument," he says.

Another suggestion is that heat given off by the Milky Way's dusty disk
has not been properly subtracted from the WMAP signals and mimics the
axis of evil. "Certainly there are some sloppy papers where
insufficient attention has been paid to the signals from the Milky
Way," warns Bennett. Others point out that the conclusions are based on
only one year's worth of WMAP signals. And researchers are eagerly
awaiting the next batch, rumoured to be released in September.

Yet Magueijo and Land are convinced that the alignment in the patterns
does exist. "The big question is: what could have caused it," asks
Magueijo. One possibility, he says, is that the universe is shaped like
a slab, with space extending to infinity in two dimensions but spanning
only about 20 billion light years in the third dimension. Or the
universe might be shaped like a bagel. Another way to create a
preferred direction would be to have a rotating universe, because this
singles out the axis of rotation as different from all other
directions.

Bennett admits he is excited by the possibility that WMAP has stumbled
on something so important and fundamental about the universe. His
hunch, though, is that the alignment is a fluke. "However, it's always
possible the universe is trying to tell us something," he says.

Clearly, such a universe would flout a fundamental assumption of all
big bang models: that the universe is the same in all places and in all
directions. "People made these assumptions because, without them, it
was impossible to simplify Einstein's equations enough to solve them
for the universe," says Magueijo. And if those assumptions are wrong,
it could be curtains for the standard model of cosmology.

That may not be a bad thing, according to Magueijo. "The standard model
is ugly and embarrassing," he says. "I hope it will soon come to
breaking point." But whatever replaced it would of course have to
predict all the things the standard model predicts. "This would be very
hard indeed," concedes Magueijo.

Meanwhile the axis of evil is peculiar enough that Bennett and his
colleague Gary Hinshaw have obtained money from NASA to carry out a
five-year exhaustive examination of the WMAP signals. That should
exclude the possibilities of the instrumental error and contamination
once and for all. "The alignment is probably just a fluke but I really
feel compelled to investigate it," he says. "Who knows what we will
find."

Lerner and his fellow sceptics are in little doubt: "What we may find
is a universe that is very different than the increasingly bizarre one
of the big bang theory."

>>From issue 2506 of New Scientist magazine, 02 July 2005, page 30

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