The term “just so story”
refers to a poorly substantiated narrative in science that is told to
explain something. Modern cosmology tells us a “just so” story to
try to partially explain why the universe started out in such an
exquisitely balanced state. Part of that “just so” story is the
theory of cosmic inflation, the narrative that the universe underwent
a period of exponential expansion in the first second of its
existence. We are told that this special period of super-fast
expansion lasted just a fraction of a second.
Being used to reading
triumphalist accounts of modern cosmology, I was pleasantly surprised
to read the candid recent account in the very readable book At the
Edge of Uncertainty by Michael Brooks, who has a PhD in quantum
physics. In his chapter “Complicating the Cosmos,” Brooks paints
a picture of a cosmology standard story that is showing many cracks. He
cites Michael Turner of the University of Chicago as saying that the
cosmic inflation theory is duct-taped and perhaps within a decade of
falling apart.
Brooks cites the work of
scientist Michael Longo:
Out of 15,000 visible
galaxies, roughly 7 per cent more are “left-handed” than
“right-handed.” The chances of this being a statistical fluke are
about 1 in a million. Especially since, when you look at the southern
sky, you see the same effect, but in reverse: more right-handed
spirals than left...This means the universe was born with a spin. And
if it has a spin, it also has an axis. And if there's one thing the
universe isn't meant to have, according to the standard theory, it's an
axis.
Read the account here for a more detailed discussion.
Brooks
then discusses the problems with the Big Bang theory and lithium:
We now know that the
cosmos contains one-third the amount of lithium-7 that the Big Bang
theory says it should. We also know that there is too much lithium-4,
which one less neutron in its nucleus. One thousand times too much,
to be precise.
Off by
a factor of 1000 – could it be our cosmologists are missing a thing
or two (or perhaps 50 or 100)?
Describing
a scientific paper by Paul Steinhardt, Anna Ijjas, and Avi Loeb
(described by Brooks as Harvard's head of astronomy), Brooks says the
following:
The Planck mission has
ruled out all but a handful of possibilities for inflation, the paper
said. Worse, the ones that disappeared were far more “natural”
candidates than the inflation models that provide the best fit to the
cosmological data, making them even less likely to be useful
resolutions of the horizon problem and the flatness problem.
Brooks
then describes an additional huge problem for the cosmic inflation
theory created by findings about the Higgs boson. Brooks says, “Once
we start adding in solutions to these problems – if we can come up
with them – the Big Bang theory will start to look less like a
coherent narrative and more like a dreamscape: a mad whirl of
disconnected stories.”
Brooks
interesting book appeared in 2014, and since then two additional
“cracks” may have appeared in our cosmologists' “just so”
story of cosmic origins. One is the situation discussed in this
paper. The standard assumption of cosmic inflation predicts a
universe that is spatially flat, without any spatial curvature. But
according to that paper, the latest results from a Baryon
Oscillation Spectroscopic Survey (BOSS) are in conflict or “tension”
with the idea of a flat universe, and are more consistent with an
assumption of a non-flat universe with a positive spatial curvature.
Still another recent
“crack” in cosmological assumptions may be the recent discovery
of a structure called the largest structure in the universe, “a
ring of 9 gamma ray bursts (and hence galaxies) 5 billion light-years
across” according to this account. Structures that large simply
should not exist, according to thinking such as the cosmic inflation
theory and the Cosmological Principle (the idea that the universe is
the same no matter which direction we look in).
Perhaps such findings
should instill a sense of humility in our cosmologists, and make them
less likely to speak as if they understand exactly how the universe
got to be this way.
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